Thursday, August 28, 2014

Rationalism and the International Dateline

There were many fascinating comments written in response to my post "No, I Am Not Desecrating Shabbos," about the international dateline and halachah. It would be great if someone would write a full halachic treatment of this topic from a rationalist standpoint. I can't do this myself, but I would like to point out some things that such a work should take into account:

1) Chazal (at least, those in Babylonia) were of the view that the world is basically flat, with a slight rise to Israel and Jerusalem at the center. (See my monograph The Sun's Path At Night for sources.)

2) The Rishonim, for the most part, knew that the world is a sphere. However, they believed that the lower half was entirely uninhabited. To quote a comment by R. David Ohsie: "The Rishonim, like others, made the assumption that the inhabited part of the world spanned approximately 12 timezones. Naturally, the eastern edge had the earliest times and the western edge had the latest times. There was no need for a "dateline" per se because civilization did not wrap around the globe. The question of where exactly the day turns would be completely theoretical and probably was not considered important; it certainly had no meaning in halacha."

3) Most recent halachic authorities to weigh in on the topic of the dateline probably did not realize/ accept the previous two points. (A notable exception would be R. Menachem Kasher.)

4) To what extent can a halachic dateline be implemented? Here is another fascinating comment from R. David Ohsie:
I want to point out one other huge problem with any "degree" based dateline, especially ones that are close to Asia. We have a general principle that the Torah can be applied with the technology available in ancient times. Anything that requires modern technology, such as a microscope, is not considered imperative. Now in ancient times, there was no way to measure latitude accurately, nor generally to map the extent of landmasses. So to say that the halacha requires you to know that Indonesia is less than 90* from Jerusalem while Japan is greater than 90* or that the western tip of Australia is less than 90* from Jerusalem while you are sitting in the eastern side would be beyond what the halacha required. So more than the fact that the Torah never says where the dateline is, it could not have required a dateline, since that would require the knowledge of modern technology to implement.

5) There is a basic distinction between the mystical and rationalist schools of thought regarding concepts such as sanctity, whether of items, rituals or dates. According to the mystical school of thought, the sanctity of these things exists as an actual metaphysical entity. According to the rationalist school of thought, on the other hand, the sanctity of these items is a state of designation. For extensive and excellent discussion, see Menachem Kellner, Maimonides' Confrontation With Mysticism (which is the most fundamentally important book for anyone interested in rationalist Judaism).

114 comments:

  1. I think that in 4 R. Ohsie meant "longitude", not "latitude" I'm not an expert, but from what I know about ancient astronomy and timekeeping I have a gut feeling that with the available technology longitude differences could have been measured to within 15 degrees, if not to within 5 degrees, based on the timing of lunar eclipses. Of course it would have taken months if not years for messages to travel between Japan and Jerusalem so the different times could be compared, but once a longitude difference estimate is established the quantity being measured won't change. If memory serves, in the late 15th century the experts who rejected Columbus' proposal to sail to the Indies by sailing west rejected the proposal on the basis of Columbus having greatly overestimated the east-west extend of Asia, and those estimates were based on the timing of lunar eclipses.

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  2. I think the quote should read, "...no means of measuring LONGITUDE accurately. The ancients were pretty good at measuring latitude. Also, the fact that the earth was round was common knowledge to the early Greek and Babylonian astronomers. iAs far back as the 2nd century BCE, Erystothanes of Cyrene not only proved the Earth was round but accurately determined its circumference.

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  3. I don't have the text to hand, and can't find it online, but I believe that the Baal HaTanya in his Kuntress Acharon on Shulchan Aruch HaRav (se'if 2) says that kedusha of time depends on local custom. In other words, the metaphysical reality of kedusha of a place is dependent on the time that the people there sanctify that time. This is the reason (I think) that Lubavitchers have no problem living in places like Hawaii and New Zealand which are dateline problematic (according to some). This is also the reason that they keep one day yomtov if they are in Israel (even if they have no intent to stay).
    This shows that the distinction between rational and mystical is not so straightforward when it comes to halakha (because the Baal HaTanya was certainly not a rationalist according to your definition).

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  4. First, I think you misunderstand the state of cosmology in the Sasanid Empire, which includes the Bavel of the Amoraim, and of Persia/Iran during the tannaim. They believed the world was a sphere that floated on the water. Not flat. Unless they thought that only a tiny bit of the top of the sphere emerged from the water, they thought that the world was significantly rounder than you describe. It was likely an entire hemisphere, with a semi-spherical sky-shell around it.

    Second, the astrolabe was invented in the mid-2nd cent BCE. By the time you get to churban bayis, they were in common use for navigating. There was no question that sailors knew the world was round. So, unless you think that Chazal were as anti-rationalist as Christianity's expectations for the masses during the early and middle Medieval periods (the "Dark Ages") they weren't ignoring or denying accepted knowledge about the earth being round.

    For that matter, the astrolabe was a decent tool for knowing when they were 90 deg from Jerusalem. Indonesia would only have been an issue if someone living before the zugos was traveling there. But since when does halakhah have to be determinable in arcane cases in order to be accepted as law, anyway? Isn't the literature rife with rulings based on the case being grey area, ie safeiq? I don't see RDS's point.

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  5. Rabbi Slifkin, just curious, Are you aware that the Zohar clearly describes the earth as round?

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    1. Of course!

      Just curious. Are you aware that Chasam Sofer held that most of the Zohar was composed in the 14th century?

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    2. I hear. So just trying to get the rationalist view clear. We take a d'aas yochid approach on anything just to fit the agenda. Do you also honestly believe that defining 6 days of creation as "non literal" (due to one shita) is not a stark violation of rationalism?

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    3. The rationalist approach is to accept the truth from wherever it comes.

      What's your approach?

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    4. You failed to answer the question.

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    5. No, I answered it. If there's only one view that acknowledges that the world is round, or that there was an age of dinosaurs, etc., then so be it. (Halachah functions differently. The age or shape of the world are a matter of metzius, not halachah.)

      What's your approach?

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    6. So basically you provide (according your view) scientific proof that the torah is non rationalist! Yet all you keep doing is bashing chareidim for their adherence.

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    7. Ok.6 days of creation.Does defining the TEXT as non literal, fly in the face of rationalism yes or no?

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    8. Dear RT
      I would suggest you back off from interrogating RNS on when he would accept a daas yochid. I have "been there, done that"....
      A year ago I questioned him why he shrugs off the Chinuch as only a daas yochid whose view is that daas torah applies not only to the Sanhedrin but also includes the chachamim of every generation, yet he happily quotes the radvaz a daas yochid that the protection of limmud torah is very confined.
      He never responded.
      Leave the man alone. I come on this site just to humour myself after a long day at work.

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    9. "So basically you provide (according your view) scientific proof that the torah is non rationalist!"

      I don't understand what that sentence means.

      "Ok.6 days of creation.Does defining the TEXT as non literal, fly in the face of rationalism yes or no?"

      Actually, I think that the text is literal. See my book for further discussion.

      For the third time: What's your approach? (It's not polite to keep posing questions to me and to continually refuse to answer the same question when it's aimed at you.) How do you decide which opinions to follow?

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    10. Moish - the Chinuch is indeed a daas yochid, and in a purely halachic matter such as the nature of rabbinic authority, there is no reason to follow a daas yochid (and a minor one at that) against the mainstream Rishonim.
      Regarding the alleged protective powers of Torah and their functioning as an exemption from military service, there is no mainstream/ majority opinion in the Rishonim saying any such thing. The Radvaz is simply an example. It's not as though there are numerous counter-examples. (Not to mention the fact that this is an issue on which we can look at the metzius.)

      What's your approach? Why do you follow the daas yochid of the sefer hachinnuch?

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    11. "We take a d'aas yochid approach on anything just to fit the agenda."

      rt:
      The following gedolim wrote works arguing for the zohar's medieval authorship:
      Yihyah Qafih, r' Yakkov Emden and Leon of Modena (milchamot Hashem, mitpachat sofrim and ari noham). Many others didn't trust it like Abraham Zacuto and Rivash.
      Anyways to the point, it's far from being a daas yochid

      Moshe

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  6. The reason I am not responding is simply because I was awaiting your response so that the conversation can flow. The definition of rationalism is, what would a simple reading of the text indicate. Now, if you would take a poll, of 100 people 99 of them would define it as literal. For starters the yirushalmi says the world is round! That is one of the places I get my opinions from. Once again once we have the value system in place i.e. rationalism,I will be glad to answer you fully.

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    1. That's not exactly the definition of rationalism, but let's go with it for now. Do you go with a simple reading of the text of the Pesukim and the Gemara which say that the kidneys and heart make decisions? How about the pesukim which say that the earth doesn't move, which all Rishonim and many Acharonim took as literal? How about the Rabbah bar bar Chana stories? Even more to the point, how about the text of the Gemara which says that the sun goes behind the sky at night? I suspect that you are pretty inconsistent about which texts you take literally. I have a much more consistent methodology.

      Even IF the Yerushalmi means that the world is round (which is not at all clear - see http://parsha.blogspot.co.il/2010/11/alexander-great-ball-on-plate-and-snake.html) - it would only provide evidence of what the Yerushalmi held, not the Bavli. That's why I worded the post in the way that I did.

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  7. Rabbi Slifkin, I have NEVER claimed to be a "rationalist". But YOU HAVE. So please respond to question once again. Is it rational to go against all odds and claim that the torah never intended to claim that 6 days were literal??

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    1. I already answered that. I indeed agree that 6 days is to be interpreted literally. I just don't think that the literal meaning is factual-historical - it is not rational to believe that there was no age of dinosaurs. See my book for elaboration.

      You don't claim to be a rationalist, but you presumably claim to have some sort of system for deciding which views and interpretations to follow. What is that system?

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  8. "I believe that the Baal HaTanya in his Kuntress Acharon on Shulchan Aruch HaRav (se'if 2) says that kedusha of time depends on local custom. "

    I just spent a week in Alaska; the only Orthodox synagogue in Alaska is a Lubavich Center and it observes Shabat on the usual Friday night to Saturday that one would expect given the secular date line. I asked whether there were any Jews in Alaska, and what they did, when in 1867 the date line was moved from the eastern border of Alaska to the Bering Straight but nobody knew for sure.

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  9. "The definition of rationalism is, what would a simple reading of the text indicate."

    Really? Exodus 6:6 - " The LORD regretted that he had made human beings on the earth, and his heart was deeply troubled." So a rationalist is to believe God has a heart, and thought He made a mistake by creating Man? That is, after all, the simple reading of the text....

    Wrong. The definition of rationalism - insofar as Judasim is concerned - is: How would a reasonable man on the street understand something, if not encumbered by doctrine or theology? In the example I gave, a reasonable man would say it's an obvious metaphor. And that's what a rationalist would say. In the dateline discussion, a reasonable man would say it is obvious rabbis of ancient Babylonia had no conception whatsoever of such a concept, and thus one cannot bootstrap unrelated statements from which to create a "halacha."

    There are some minor quibbles one can raise with the definition I've stated, but by and large it is accurate. And here's a little secret: Chazal used the same definition, from kashrus to marital issues. It's called masiach lefi tumo.

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    1. You seem to know as little about Agunos as about theology. Mesiach lefi tumo does not mean what you claim it does. Neither is the Torah's opinion as you say it.

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  10. Whats that supposed to mean??If its not factual history,then are you suggesting that the torah is saying something that is not factually true?! The mere fact that I have to go get your book before reading the torah,is the biggest contradiction to rationalism possible!!!!!

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    1. Yup, you'll have to read my book. Though I don't really recommend it for you. Suffice it to note that "literal but not factual" is how several Rishonim explained several parts of the Torah.

      But this is straying from the topic, and I don't let comment threads go off-topic. You claim that one should interpret a text according to its plain meaning. Yet you apparently refuse to accept the plain meaning of the Bavli that the sun goes behind the sky at night, and other such texts. Why? Indeed, Shevus Yaakov rejected modern science because it goes against the plain meaning of the Gemara that the world is flat. And numerous Acharonim rejected heliocentrism because it goes against the plain meaning of pesukim that the world is stationary. The plain meaning of texts supports the points that I made in this post.

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  11. DF. Lets take a poll and see how they would respond to defining each of those verses.

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    1. LOL. You mean a poll of a particular group of people today, who have preconceived theological notions, or a poll of people in antiquity?

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    2. (Rambam, by the way, held that such pesukim are literal but not factual. See Guide 1:26)

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    3. He says the Torah talks in the language of man and therefore uses language to denote perfection for Hashem based on what is perfection in man. The masses he says has difficulty imagining Hashem without anthropomorphisms he says and so to denote perfection in Hashem the Torah uses these terms for Hashem without really meaning they are really true regarding Hashem. The Rambam believed Judaism is totally true and therefore that the Torah had to be totally true. To say otherwise of any Rishon or Acharon would be it seems to me a contradiction to their believing likewise that Judaism is totally true.

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    4. YA, so you're saying that Rambam held that the Torah is totally true but not really true?

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    5. He said that the Torah is totally true but that it uses language that would if taken literally be conveying falsehoods. According to the Rambam the ignorant take them literally but they are only allegories meant to say something different. For instance Hashem being described as very angry would only really mean He is very disapproving. He says a word can mean one thing when describing people and another when describing God. It is the job of the educated the Rambam says to tell the ignorant various truths about Hashem so that even if they are too limited in intelligence or training to understand how something in the Torah is an allegory they will understand it must be. It goes without saying that if he would say the Torah is not totally true he would either have been ignorant of what the implications of his words were rather than being a clear and thoughtful thinker or he would have been aware and so would have been a nonbeliever.

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  12. Why don't you recommend it? In addition, I never claimed that the verses needed to be interpreted in any particular way.

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    1. From the introduction:

      This book was written for those who are committed to the tenets of
      Judaism, but also respect the modern scientific enterprise and are aware
      of its findings, and who are therefore disturbed by the challenges that
      are raised for their understanding of Torah. It addresses these challenges
      by adopting the rationalist approach of Rambam (Maimonides) and
      similar Torah scholars towards these issues, which is not the method
      of choice in many segments of the ultra-Orthodox community. But
      many have found that no other approach works as well in solving these
      difficulties.
      Other people may not possess as extensive a background in the
      sciences or may dispute the validity of the modern scientific enterprise.
      They may therefore simply not be bothered by the questions discussed
      in this book, or they may have different ways of dealing with such
      conflicts. Such people are not the intended audience of this book and
      they are advised not to read it.

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  13. This thread is risking going totally off-topic, so here is a heads-up: I will only be allowing comments that relate to the topic of this post, i.e. cosmology (the shape of the earth) and the dateline.

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  14. How did the yirushalmi, rashi ibn ezra, etc.. know about a round world, if the scientists at that time were unaware of it?

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    1. Why do you say that the scientists at that time were unaware of it?

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  15. This is just Lashon HaRa on Chazal.
    The Ba'al HaMa'or clearly believed that Chazal held the world to be round in shape. His pesak on the dateline is predicated on that. The Ra'avad does not appear, to the un-jaundiced eye, to disagree. The Rishonim that talk about astronomy claim that da'as chachomeinu is that the world is round.
    The source that Chazal held different is open to alternative explanations and only an agenda to separate Chazal from the truth would make a person make an unequivocal statement that Chazal believed the world to be flat..

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    1. That is simply incorrect. In my monograph on the sun's path at night you can find dozens and dozens of Rishonim who accepted that the chachmei Yisrael believed the sun to go behind the sky at night. The Shevus Yaakov - an Acharon - rejects science because scientists go against Chazal's position that the world is flat. See http://parsha.blogspot.co.il/2009/06/was-shevus-yaakov-flat-earther-it-would.html
      Only someone with an agenda to make Chazal accord with scientific truth would make an unequivocal statement that Chazal believed the world to be round.

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    2. So the Ba'al HaMa'or had an agenda to attack Slifkin? Talk about healthy self-esteem !

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  16. While not coming from a strictly 'rationalist' perspective, R. Yehuda Schwadron's articles on this topic in Beis Aharon Veyisrael (volumes 147, 148 and 149 - all of which are available on Hebrewbooks.org) are nevertheless extremely valuable. His critique of the Chazon Ish in particular contains much that any rationalist could identify with, as does his demonstration that the minhag is generally not in accordance with the Chazon Ish. That said, the reactions in the 'teguvos' sections of volumes 148 and 149 demonstrate that supporters of the Chazon Ish's position have indeed considered many of the issues R. Ohsie raises, although I doubt he will be entirely satisfied by their arguments.

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    1. Thank you for the references. I'm starting a collection...

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  17. Not being a rationalist would be very hard on a thinking person's belief in Judaism. How could one believe that our religion was given to infallible, all knowing people? This is one of many examples that proves that Hashem wanted us to use what we learned to think about and solve problems.
    Only G-d is all-knowing.

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  18. As per point number 2, that would make the dateline unimportant but not theoretical. If chazal/rishonim were working with the assumption of a round earth where only 12 time zones are inhabited, that may have meant that the date line was on the other side of the world, but it still existed. If a person traveled there, they would have to worry about the issues of the dateline. Regardless of how you envision the earth, if it's round, how big, etc., you still have to deal with the issue of sunrise being in a different place at different times and only one of those places can be the start of the new day. A person crossing over that line will be traveling into the new day/old day. I guess my point is they must have had some kind of a conception of the issue, because as far as I can surmise, it isn't dependent on having a round globe, it should exist regardless as long as you understand that sunrise slowly moves westward. Maybe I'm missing something.

    As far as point number 4, maybe we could put this whole discussion somewhat into the realm of minhag. This is particularly true for the opinion that holds that since the entire world recognizes a single international dateline, we as Jews can adopt and implement that line halachically. Other halachot/minhagim are based on cultural norms (begged isha perhaps being an example), and this would definitely fall into that category.

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    1. As per point number 2, that would make the dateline unimportant but not theoretical. If chazal/rishonim were working with the assumption of a round earth where only 12 time zones are inhabited, that may have meant that the date line was on the other side of the world, but it still existed. If a person traveled there, they would have to worry about the issues of the dateline.

      But no one did travel there, so there is no need for a line except theoretically. Here is some evidence that they did think this way. (In the following, Socrates and Plato are two travelers going around the world, one going east and one going west:

      “From this it follows that if this [equatorial] zone were everywhere habitable, one ought to assign a definite place where a change of the name of the day would be made, for otherwise Socrates would have two names for the same day and the other [Plato] would have the same name for two days.” [emphasis mine]

      This is from http://www.staff.science.uu.nl/~gent0113/idl/idl_early.htm

      Regardless of how you envision the earth, if it's round, how big, etc., you still have to deal with the issue of sunrise being in a different place at different times and only one of those places can be the start of the new day.

      Here is the easy way to think of it. Suppose that the habitable world consisted only of the land of Israel as an island. I think that there would no question of what day it is.

      As far as point number 4, maybe we could put this whole discussion somewhat into the realm of minhag.

      I need to dig more deeply, but the Yesod Olam definitely ascribes the notion where the day (ie in the east) to man's choices.

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  19. It did not become common knowledge until Columbus came around. There were debates about it and there was no clear knowledge. Yet to rashi, the, even ezra and others it was obvious. Rashi's interpretation of the world being round comes from a verse in tehilim not from the science of his day.

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    1. It is a myth that Columbus corrected anything. The sphericity of the earth was accepted by all the renowned Greek writers and in mainstream thought. That's where Ibn Ezra, an ardent student of Greco-muslim philosophy, got it from.

      Which Rashi are you referring to? It's not at all clear that Rashi held the world to be round. (Rashi did not study Greco-Muslim philosophy.) See http://parsha.blogspot.co.il/2011/01/eastbound-locusts-was-rashi-flat.html and http://parsha.blogspot.co.il/2009/07/was-mizrachi-flat-earther.html.

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    2. Also, as R. David Yehudah Leib Silverstein points out in Shevilei David, Orach Chaim no.
      4 55, p. 96b, Rashi appears to have maintained the Babylonian cosmology, whereby the dome of the firmament meets the edges of the earth; see Rashi’s comments to Ta’anis 25b, s.v. Bein Tehoma.

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    3. Sorry it's rashi in isaiah40:22

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    4. LOL, you are funny. That Rashi is saying the opposite of what you think. He is saying that the world is a disc! The Old French word, compas, means a circle, not a sphere. And note his comments to the end of the passuk, which he understands (as in Taanis) as referring to that the edges of the firmament touch the edges of the world.

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    5. Disagree, he is translating a verse, which even you I hope agrees is authentic. Circle only has relevance if it's spherical .In other words the word "circle" kind of teaches us that the world is spherical.

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    6. What do you see Rashi as adding to what the verse says?

      It is most certainly not true to say that "Circle only has relevance if it's spherical." A plate is (usually) a circle.

      The Old French word "compas" has a meaning, and that meaning is not "sphere."

      It's so ironic that you earlier insisted that a verse should be read according to its plain meaning. The plain meaning of this verse is that the world is a disc with the hemispherical dome of the firmament on top of it. Due to your particular religious and scientific convictions, you refuse to read it this way.

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    7. I think you're missing my point entirely. The possuk uses the word "CHUG". What is the definition of that word. Is it a sphere? or circle?.The answer obviously is-a sphere, since that is the factual reality. So now when rashi explained the definition of the word, was he correct in his interpretation or not? If you answer that he was WRONG, because rashi held it was a circle and NOT spherical, then it turns out that you are claiming that rishonim are incorrect scholastically (not just scientifically) as well. Additionally the claim would have to be the same for the even ezra there as well. Therefore, it would be a lot safer to say that rashi meant circle as in spherical ball.

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    8. LOL. So you are starting off with the religious premise that the passuk must be scientifically correct. And since you also have the religious premise that Rashi must be correct in his explanations of the Torah, so Rashi must also be scientifically correct! So it makes no difference what Rashi actually says, he must be scientifically correct!

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    9. Is a premise that the verse is scientifically correct up for debate? I don't think so. So once we KNOW what the possuk means, we can assume rashi means the same since it's more likely that rashi did not get the definition WRONG,then saying rashi meant DAVKA a circle and not a SPHERE.

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    10. Sure it's up for debate. Unless you hold that the opinions of various widely respected Rishonim and Acharonim are not allowed to be considered.

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    11. You mean g-d was only aware of the science available at the time?

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    12. In the posuk in Yeshaya it would be accurate to say "above the circle of the earth" even with the earth being a sphere. The picture being conveyed is of Hashem above and the earth below. From that point of view earth looks like a disk however much it may rise northward like an island.

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    13. My chavruta and I spent a long time analyzing the Rashi in Pesachim, the one in Taanit, and the one in Rosh Hashana. We also looked at the Tosaphot in those mesechtot. We both came to the conclusion that they could only be read by assuming a flat Earth. Now it is possible that both Rashi and the later Tosaphists actually knew the Earth was round, but commented in the way they did because they felt Chazal were talking about a flat Earth in those sugyot. But according to you two, that would mean that Rashi was able to supernaturally derive more out of that pasuq in Tehillim than Chazal were. And not only that, but Rashi would have had to acknowledge they missed that bit, even though wisdom was given to him somehow. Which is a conclusion that is somewhat troubling, and I would gather, even more troubling to you.

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    14. reshash in pesochim also says that tosfos held of a flat earth

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  20. Also of relevance is the statement of the Gemara in Shabbos 65b, regarding rainfall in Israel resulting in a rise in the Euphrates (and see the comments of Rashi and Tosafos ad loc.).

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  21. I think that in 4 R. Ohsie meant "longitude", not "latitude"
    I think the quote should read, "...no means of measuring LONGITUDE accurately.

    (Please call me David). Yes, I meant longitude. But this helps let me know that someone is reading :).

    I have a gut feeling that with the available technology longitude differences could have been measured to within 15 degrees, if not to within 5 degrees, based on the timing of lunar eclipses.

    I'm not sure that the error would have been, but as you point out, one of Columbus's errors was to overestimate the extent of the Eurasian landmass. The other was to adopt an estimate for the circumference of the earth that was too small.

    But, practically speaking, we see that the Rishonim simply didn't know because they gave the distance from China to the "west" as 180* when it is more like 135* to the western edge of Africa.

    First, I think you misunderstand the state of cosmology in the Sasanid Empire, which includes the Bavel of the Amoraim, and of Persia/Iran during the tannaim. They believed the world was a sphere that floated on the water. Not flat.

    While I have little doubt that some members of Chazal probably knew that the earth was round, if you look at Pesachim 94a you will see that at least some believed the earth to be flat. The arguments on that page are not sensible otherwise.

    Unless they thought that only a tiny bit of the top of the sphere emerged from the water, they thought that the world was significantly rounder than you describe. It was likely an entire hemisphere, with a semi-spherical sky-shell around it.

    This seems unlikely at first thought (although actual scholarship would be more useful there). Such as shape would imply the land meeting the sea at the edges at a 90* angle. Did they really believe that?

    For that matter, the astrolabe was a decent tool for knowing when they were 90 deg from Jerusalem.

    I think that is a mistake. You can determine latitude with an astrolabe by measuring the elevation of the polestar. Determining longitude requires knowing what date and time it is; the stars revolve around the polestar and some rise and set as the night goes on. It is a much harder problem. You need a clock (terrestrial or celestial).

    Indonesia would only have been an issue if someone living before the zugos was traveling there. But since when does halakhah have to be determinable in arcane cases in order to be accepted as law, anyway? Isn't the literature rife with rulings based on the case being grey area, ie safeiq? I don't see RDS's point.

    Of course it is not impossible, but it seems unlikely that the Torah indicated that the line was 90* when there was no way to determine 90*. The six days work + one day rest seems much more likely.

    Rabbi Slifkin, just curious, Are you aware that the Zohar clearly describes the earth as round?
    Just curious. Are you aware that Chasam Sofer held that most of the Zohar was composed in the 14th century?
    I hear. So just trying to get the rationalist view clear. We take a d'aas yochid approach on anything just to fit the agenda.

    Rt, I don't think that the late dating of the Zohar is a Daas Yachid among "rationalists". See for example, the Kapach family endorsement of that position. The the Zohar itself is not exactly a rationalist text and the claimed story of the Zohar's discovery is not "rational".

    This is beside the fact that most of those who accept the antiquity of the Zohar agree that there are later interpolations, making it a book that cannot be used to reliably show what Chazal knew.

    ReplyDelete
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    1. "Determining longitude requires knowing what date and time it is; the stars revolve around the polestar and some rise and set as the night goes on. It is a much harder problem. You need a clock (terrestrial or celestial)."

      This is correct, and the first reliable and practical marine chronometers were not developed until the 18th century.

      https://en.wikipedia.org/wiki/Marine_chronometer

      Delete
    2. Those marine chronometers were invented to enable determination of longitude on a moving and rocking ship. It's much easier to do an approximate determination of local time on dry land, even at night (just use a well-calibrated hourglass, starting at sunset).

      Delete
    3. To determine longitude you need to know "absolute" time, not local time.

      BTW, the first practical method for determining longitude at sea where not based on accurate clocks. It was based on tables in the Nautical Almanac that converted the position of the Moon relative to the stars into absolute times.

      Delete
    4. It seems to me that R Yehuda Halevi and the other Rishonim pretty much thought that all of Europe, Asia, and Africa could just about fit in one day. Jerusalem was approximately in the center, so noon there would be about sunrise on one side and sunset on the other. Most of the best astronomers could calculate the circumference of the Earth to reasonable accuracy, but not the longitudinal position of any particular place.

      Chronometers were actually created just before accurate Lunar tables, and the first tables were riddled with error. The calculations involved were also difficult, and sailors were error-prone. But sextants were far cheaper than chronometers. And as even the boats that had access to chronometers could only afford one or two if the captain was particularly rich, even those captains who had them needed a failsafe.

      An hourglass won't help, but there were other calculations that could be done, provided one had a telescope and time to kill. So surveyors had access to longitudes from about 1630 on.

      Delete
    5. It seems to me that R Yehuda Halevi and the other Rishonim pretty much thought that all of Europe, Asia, and Africa could just about fit in one day.

      This is correct. Those that talk about this pretty explicitly say that the inhabited areas of the earth are twelve hours across.

      An hourglass won't help, but there were other calculations that could be done, provided one had a telescope and time to kill. So surveyors had access to longitudes from about 1630 on.

      This is great information. Where is a good reference for this? Was this based on observations of Jupiter's moons? What about pre-telescope cartography based on naked-eye observations?

      Delete
  22. rt:
    "It did not become common knowledge until Columbus came around. There were debates about it and there was no clear knowledge. Yet to rashi, the, even ezra and others it was obvious. Rashi's interpretation of the world being round comes from a verse in tehilim not from the science of his day."

    You might want to read this Wikipedia article (link). It explains that it is a "misconception that the prevailing cosmological view during the Middle Ages saw the Earth as flat, instead of spherical."

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  23. I want to correct something of an error that I made above. I believe that accurately computing longitude on a ship is a harder problem than on land with a stable platform and multiple observations over time. So arguments based on lack of accurate clocks are probably somewhat incorrect, since I believe there are way to work that problem on land.

    Nevertheless, accurate measurements of longitude were not available in ancient times and no one could have known when the crossed the 90* line from Jerusalem, let alone knowing whether the western edge of the island they resided on was within 90* of Jerusalem.

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  24. What I don't get is the following : if you believe there is no halachic dateline and we just need to pick an arbitrary spot, what value is there in choosing the secular line? Why not just take one of the lines that might actually have a mekor in shas (ie 90 or 180)?

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    1. If the line is arbitrary, then you want to pick one that creates as few issues as possible. Granted it would be nice to pick a line that is well established in halachic literature, but we don't want a situation where the world says a certain location is on one side of the zone, but halacha says it's on the other. That creates all sorts of confusion. Choosing the internationally recognized dateline removes all issues and, as mentioned above, there are opinions that hold that since there is a universally accepted line, it can be adopted halachically.

      Delete
  25. ConfusedAugust 31, 2014 at 12:14 AM
    What I don't get is the following : if you believe there is no halachic dateline and we just need to pick an arbitrary spot, what value is there in choosing the secular line? Why not just take one of the lines that might actually have a mekor in shas (ie 90 or 180)?


    1) Just to give some context, this appears to be the position of the Rav Tzvi Pesach Frank and Rav Isser Zalman Meltzer based on the Teshuva of Rav Tzvi Pesach and the letter of Rav Isser Zalman. This was described at length by Rav Menachem Kasher.

    2) Their idea is that there are two basic halachas: one counts six days and then keeps the seventh. This doesn't change via the crossing of any arbitrary line. The other issue is that when you get to a place where others have already established a day for Shabbos, you go with that. (How those interact is a gray line; see for example here for an opinion dealing with a person who travels from Brazil to Australia and thus "loses" a day. http://www.hebrewbooks.org/pdfpager.aspx?req=713&st=&pgnum=30)

    3) Thus, the advantage of going with the "secular" day is that it generally corresponds to both the 6+1 pattern and the existing Minhag. Many of lines like 90 and 180 force you to change the existing Minhag for that place and/or make short travel not conform to the 6+1 rule (e.g. 90* cuts through East Asia, 90* + Chazon Ish makes Japan change, 180* makes Hawaii and much of Alaska change). The "mid pacific poskim" as show in this table would not have this problem much, if at all: http://www.star-k.org/kashrus/kk-trav-dateline2.htm

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  26. R Tzvi Chajas writes in his glosses at the beginning of Taanis
    ומזה גם כן ראיה למה שהחליטו כלם דהפירוש המיוחס לרשי אינו מרשי רק מתלמיד אחד

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  27. so just to clarify. the position of the Rav Isser Zalman Meltzer and the others is that A) there is NO dateline recognized in halacha? or B) because there is no mekor for the dateline, we need to pick an arbitrary spot (and we may as well pick the secular one)? Obviously, there is a huge difference between the two as a very small percentage of the globe has an existing minhag...............

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  28. confusedAugust 31, 2014 at 6:18 PM
    so just to clarify. the position of the Rav Isser Zalman Meltzer and the others is that A) there is NO dateline recognized in halacha?
    or B) because there is no mekor for the dateline, we need to pick an arbitrary spot (and we may as well pick the secular one)? Obviously, there is a huge difference between the two as a very small percentage of the globe has an existing minhag...............


    This question is ill-formed, because "dateline" is not well defined. If you travel around the world towards the east from Los Angeles on a halachic Monday and land in Melbourne on halachic Tuesday, you will have moved forward one day without experiencing a sunset. If that is the definition of "dateline", then everyone agrees there is one. But that doesn't mean that the day changed because you crossed a line established during the six days of creation.

    Also, I don't know that Rav Meltzer and Rav Frank actually adopted the international dateline. What I think that they said was that you can't determine the day based on a line established in the Talmud. The key factors are 6 days followed by 1 and not changing the resulting minhag of a place. I don't know any place (yet) where either wrote down rules that would cover all situations. They seemed to be concerned most about changing the existing Minhag in Japan (and possibly other locations) based on a 90* line.

    But judge for yourself (emphasis mine)

    http://www.otzar.org/wotzar/book.aspx?149342 Click on the "guest access" link and then go to page 10.

    Here is Rav Isser Zalman's letter translated:

    I also agree to the Pesak of the Bais Din in Eretz Yisrael that is based on the responsum of the Radvaz [translated above] and also the Pesak of the Shoel U'Meishiv and the Gaon Rav שמואל מוהליבר and many other Greats of Israel, that one should not change, God Forbid, the day of Shabbos any any place in the world, not to Sunday and not to Friday, and because we don't have in Shas or the Shulchan Aruch any hint that one should consider "lines" with regard to keeping Shabbos. Rather the principle is to count six days and keep the seventh, and in all places in the world, they should keep the Shabbos as they have kept it until now.

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    1. this contradicts another letter of Rav Isser Zalman'

      Delete
    2. genozim and shut chazon ish claims this letter is kasher forgery partly because the letter we have from Rav Isser Zalman says (as far as I recall)it is a machlokes between ravad and bal hamor and we should have yom kippur on wednesday and keep to shiurim on thursday

      also says the beis din in eretz yisroel never considered a 'no dateline.'

      kasher bemoan this in 1954 why did the beis din not think of this.
      tikuchinsky dismisses it in his sefer without even deigning to give a reason.

      also minor point why call it ' Bais Din in Eretz Yisrael ' if you live there.
      also asks kasher's family to publish this letter if they have it

      Delete
    3. genozim and shut chazon ish claims this letter is kasher forgery partly because the letter we have from Rav Isser Zalman says (as far as I recall)it is a machlokes between ravad and bal hamor and we should have yom kippur on wednesday and keep to shiurim on thursday

      Don't have access to that Sefer. Where is Rav Isser Zalman's other letter published (or is it only in this Sefer?)

      also says the beis din in eretz yisroel never considered a 'no dateline.'

      Who says? The Beis Din was set up to consider Japan, not to set out general principles. No doubt the decision included those who agreed with Rav Tukachniski's Shita, but where did they rule out "no dateline"?

      kasher bemoan this in 1954 why did the beis din not think of this.

      That is strange because the "no dateline" shita is much older than the Beis Din.

      tikuchinsky dismisses it in his sefer without even deigning to give a reason.

      Yes, this is part of my theory: Rav Tukachinsky is one who insists that there must be a dateline a premise of his Sefer (based on the first part that I read). There seems to be an assumption by Rav Tukachinsky and also R' Chaim Zimmerman that this must exist. These Shitot do not even consider that there might not be a dateline. In this case, the argument is not about what the Yesod Olam means, but rather, what premises you bring to the table: a meta-halachic argument.

      also minor point why call it ' Bais Din in Eretz Yisrael ' if you live there.

      Because the telegram came from Japan?

      also asks kasher's family to publish this letter if they have it

      This is beyond my capabilities.

      Delete
    4. Also, the editor of this volume see forgeries everywhere! See Prof Marc Shapiro's Seforim blog post http://seforim.blogspot.com/2012/05/kalir-false-accusations-and-more.html.

      Genazim u-She'elot u-Teshuvot Hazon Ish, p. 227, makes the astounding assertion that this telegram [from Japan to E"Y] is a fraud, and that it was never sent from Kobe. Rather, it was a scheme cooked up by the Chief Rabbinate (i.e., R. Herzog) which arranged for a phony telegram to be sent! This would enable R. Herzog to call a gathering a great Torah scholars at which time he could push them to accept his opinion in opposition to the viewpoint of the “gedolei Yisrael.” It is hard to imagine a more outrageous accusation directed against a man of unquestioned piety such as R. Herzog.

      Delete
    5. Finally, which volume (or volumes) would I need to get in order to see the dateline discussions?

      Delete
    6. I do not know Where Rav Isser Zalman's other letter is published besides this Sefer


      kasher published a letter (in his sefer) purportedly from r. meltzer that says there should be no dateline as that is what the beis din of eretz yisroel decided.

      however if he is talking about the '41 beis din, they did not rule it out or mention it and were indeed only considering yom kippur which makes it more difficult to understand how r. Meletzer could use the beis din as a proof.


      you say 'That is strange because the "no dateline" shita is much older than the Beis Din.' I think the sefer claims kasher was the first person to think of it as his interpretation of radvaz.

      I think prof shapiro also says that there is circumstantial evidence that kasher is not being truthful about his meeting with chazon ish

      the main discussion of dateline is in vol 1 , with a bit added in vol 2

      Delete
    7. I do not know Where Rav Isser Zalman's other letter is published besides this Sefer

      Thank you.

      kasher published a letter (in his sefer) purportedly from r. meltzer that says there should be no dateline as that is what the beis din of eretz yisroel decided.

      however if he is talking about the '41 beis din, they did not rule it out or mention it and were indeed only considering yom kippur which makes it more difficult to understand how r. Meletzer could use the beis din as a proof.


      He was referencing that he agreed with the Beis Din that Japan should celebrate Shabbos on Saturday. There was clearly more than one argument in favor of that. I don't think that he was bringing the Beis Din as proof for a particular reason.

      you say 'That is strange because the "no dateline" shita is much older than the Beis Din.' I think the sefer claims kasher was the first person to think of it as his interpretation of radvaz.

      See this link http://www.hebrewbooks.org/pdfpager.aspx?req=713&st=&pgnum=30 where he says that when travelling from Brazil to Australia, one should keep his own count rather than switching to the day kept in Australia (unless he is moving there permanently).


      I think prof shapiro also says that there is circumstantial evidence that kasher is not being truthful about his meeting with chazon ish

      Read it again. He says that the discrepancies, such as they are, are in the version written much later and are likely due to a faulty memory.

      the main discussion of dateline is in vol 1 , with a bit added in vol 2

      Thank you.

      Delete
    8. also minor point why call it ' Bais Din in Eretz Yisrael ' if you live there.

      See intro to Rav Tukachinski's Hayomam. He refers to the argument among the "G'dolim of of E"Y of our time".

      Delete
    9. He was referencing that he agreed with the Beis Din that Japan should celebrate Shabbos on Saturday. There was clearly more than one argument in favor of that. I don't think that he was bringing the Beis Din as proof for a particular reason.

      ................................................

      rav metzer said according to kasher 'I also agree to the Pesak of the Bais Din in Eretz Yisrael that is based on the responsum of the Radvaz ' he is saying that the pesak was based on radvaz.


      ''''''Read it again. He says that the discrepancies, such as they are, are in the version written much later and are likely due to a faulty memory.'''''''''''

      here are I believe 3 criticisms by shapiro on kasher's reliabilty and good faith
      'Despite this defense of Kasher, it must also be pointed out that there are serious questions about the reliability of some things he published.
      '

      'The followers of the Hazon Ish have indeed always claimed that his description of his visit, in Ha-Kav ha-Ta’arikh ha-Yisraeli (Jerusalem, 1977), pp. 13-14, is not to be relied upon. Since his own recollection of his visit is the strongest evidence in favor of Kasher forging R. Isser Zalman’s letter, it is not very convincing.'


      'I do, however, have to mention that in the 1977 version of the visit Kasher adds something that is not in the original recollection and must therefore be called into question. In the original recollection he reports that the Hazon Ish began reading Kasher's work on the dateline and then said that he is tired and asked if he could hold on to the work to read later. In the 1977 version Kasher then adds the following, which shows the Hazon Ish as not very committed to his own position, a point which is at odds with everything else we know about the Hazon Ish and the dateline:'

      Delete
    10. He was referencing that he agreed with the Beis Din that Japan should celebrate Shabbos on Saturday. There was clearly more than one argument in favor of that. I don't think that he was bringing the Beis Din as proof for a particular reason.

      ................................................

      rav metzer said according to kasher 'I also agree to the Pesak of the Bais Din in Eretz Yisrael that is based on the responsum of the Radvaz ' he is saying that the pesak was based on radvaz.

      The pesak of the Bais Din was undoubtedly tied to the Radvaz's interpretation that the Yesod Olam did not agree with the Kuzari. Whether or not that is what is he meant is irrelevant though. The Bais Din came out with a Pesak, not a list of reasons. He is agreeing the pesak; the further reasons that he gives don't have to be agreed to by the Bais Din.

      ''''''Read it again. He says that the discrepancies, such as they are, are in the version written much later and are likely due to a faulty memory.'''''''''''

      here are I believe 3 criticisms by shapiro on kasher's reliabilty and good faith


      There is a difference between details about long ago conversations about which everyone's memory is unreliable and fabrication of a Teshuva or lack of good faith. You reading into Prof Shapiro something that he didn't write.

      The editor(s) of the sefer that you mentioned are completely biased: since they disagree with R Herzog, they maintain that he fabricated the telegram from Japan! And that Rav Kasher published a fabricated letter from Rav Frank while he was still alive. This is all simply bias to prove the Chazon Ish "right" (of course it doesn't really prove anything).

      That said, don't care too much about who said what and if someone wants to believe that various letters were forged, let them believe it; it doesn't really change the analysis.

      Delete
    11. http://en.wikipedia.org/wiki/David_ben_Solomon_ibn_Abi_Zimra

      the radvaz was 13 when america was discovered. I am surprised that he did not know there was a yishuv

      Delete
    12. when you say those who disagree with the Kuzari and set the beginning of the day in the "East" don't have a dateline. what would happen if on east china motzei shabbos you go fishing is that ok ?

      while agreeing from a rationalist perspective, kasher's good faith is not so important I thought shapiro is quoting positively Berkovits who accuses kasher of forging a letter.

      Delete
    13. the radvaz was 13 when america was discovered. I am surprised that he did not know there was a yishuv

      Maybe he did. His Teshuva is really discussing the existence of timezones and doesn't in any way depend on whether or not the western hemisphere is populated.

      when you say those who disagree with the Kuzari and set the beginning of the day in the "East" don't have a dateline. what would happen if on east china motzei shabbos you go fishing is that ok ?

      The answer, of course, is yes. Why would you suddenly switch days?

      while agreeing from a rationalist perspective, kasher's good faith is not so important I thought shapiro is quoting positively Berkovits who accuses kasher of forging a letter.

      He questions whether he forged something else on another topic. He finds the evidence for forgery on the dateline to be entirely lacking.

      Delete
    14. thanks for replying. I learn a lot from your posts.


      'The answer, of course, is yes. Why would you suddenly switch days?'
      ...................

      according to yesod olam if the day starts in the beginning of east asian landmass, I thought that is where the dateline would be. so sailing further east on motzie shabbos would be sailing into shabbos.

      Delete
    15. Because, as I mentioned, he is not specifically drawing a line at the edge. If only half of the world is populated, then you don't need a dateline. You just start at the east and end at the west. So if you sailed around near the east or west, you would use the same logic. The question comes up when you imagine sailing around the world, but they didn't think that was possible, so it was only a hypothetical questions.

      In other words, he didn't start from the east because he had a line at the east. He started at the east because he there was no point in drawing any line. He would certainly have included people swimming/sailing off the coast, IMO.

      Delete
    16. if someone had asked the yesod olam what happens if with kishuf you create a massive iron ship which does not sink and you take a flock of sheep for food and you sail from east china around the world, where do you cross the dateline, he would have been forced to place the dateline somewhere in the 12 hours of sea. No ?

      Delete
    17. Not necessarily, but it is hard to say. In any case, there aren't 12 hours of sea, so even if he answered the question, the answer would not necessarily be applicable. He definitely indicates that this is not an important question, as one of his attacks on the Kuzari is that the Kuzari determined the day of the week for the fish in the sea, but not for the people living between Israel and China.

      Delete
    18. Not necessarily, but it is hard to say. In any case, there aren't 12 hours of sea, so even if he answered the question, the answer would not necessarily be applicable.
      .........................................................


      thank you for your reply.
      agreed that he would not think it would be a practical important question and I can see why you would say would not necessarily be applicable.

      but when you say 'Not necessarily, but it is hard to say.' what is the other option besides placing the dateline in the 12 hours (as he saw it) of the sea somewhere

      Delete
    19. Some maintain that you count 6+1 until you reach an inhabited area and pick up their count. Others hold you stick with 6+1 until you plan to settle in the "new" area.

      Delete
  29. Rav Tzvi Pesach: http://www.hebrewbooks.org/pdfpager.aspx?req=20947&st=&pgnum=154

    It has been about 10 years ago since the question arose via the escapees who settled in Japan and China about the dateline for Shabbos and Yom Kippur, and I was asked how they should practice in such places.

    I answered that it was incumbent on them to practice in accordance with that which was already established in those places without change from [the practice of] the people who were already to be found there.

    And behold in these days, some Talmidei Chachimim, and among them great rabbis, come out [with statements] that in their opinion, those who are immigrating to these places must change the day of Shabbos as well as Yom Kippur. You provided a great benefit, my friend [Rav Kasher], by entering into the depths of this matter to explain it according the Torah's precepts, and you collected many statements of the greatest of their generation who spoke on this matter. The first amont them being the Radvaz who decided as a matter of practical halacha that someone that arrives from a distant location must keep Shabbos in accordance to the residents of that place. Ans this is also the position of the Rabad and Yesod Olam who argue with the Kuzari. And recently in Jerusalem was published the book of the great head of Bais Din from Bialystok, the great Rav שמואל מוהליבר of blessed memory who "shook worlds" [to protest] against those who wanted to change the day of Shabbos.

    Inasmuch as this endangers the observance of Shabbos in [the nation of] Israel, there is a holy imperative on the greats of our generation to stand at the watch, in order to erect a fence, that these people will not come, God forbid, to breach the holiness of Shabbos. And especially, since the main reason given to change the [day of] Shabbos is the dateline that was established by the nations of the world, because there is no foundation in the Talmud or later authorities that there exists a dateline; this itself is a clear proof that, in fact, the date is not established by the Torah, because [otherwise] how could the Torah be missing such a [important] principle which is relevant to the establishment of Shabbos. Rather, perforce, [the halacha is] in accordance with that which the Radvaz wrote, that the Mitzvah of Shabbos is such that in each place one works six days and rests on the seventh day, in accordance with the plain language of the Torah in all places [in the Torah] where the Torah prohibits [work on] Shabbos. Once should not deviate from this [principle]. An anyone who comes to change this [principle] without proof from the Torah should fear for his soul that he is not, God forbid, among those who cause the masses to sin, especially since this is one of the foundations of the Torah. And one who heeds [these words] will be blessed with all manner of good.

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    1. do you agree with rav frank that ravad and yesod olom support his no dateline opinion ?

      Delete
    2. I would say that any of the Rishonim who disagree with the Kuzari and set the beginning of the day in the "East" don't have a dateline.

      Yesod Olam goes even farther in saying that while from the perspective the the days of creation, the Seventh day started with sunrise in the east, from the point of view of man, the first day was stretched out to 36 hours to accommodate and extra 12 for the sun to get to where it was sunset in the East. So he definitely takes the perspective that man is involved in the establishment of the day. Since a lot of his reasoning is based on the assumption of no habitation in the western hemisphere, it is hard to extrapolate, but he there is not indication of a need for a dateline and indication that man plays a role in setting the days. I need to read it more carefully.

      Delete
  30. Question via email:

    You quote R' David Ohsie as saying:
    "So more than the fact that the Torah never says where the dateline is, it could not have required a dateline, since that would require the knowledge of modern technology to implement." This is taking a question and making an answer out of the question - there is no dateline. The conclusion is more absurd than the question. Since the world is round there must be a dateline. This is a reality just as nighttime follows daytime. The existence of a dateline is non- negotiable. Anyone who says otherwise doesn't understand the nature of the dateline. The only question is where it is?
    Regarding his question - How is the man of Matan Torah supposed to measure it - If the Chazon Ish is correct that the Asian coastline is the dateline then no sophisticated measurements are needed. If on the other hand the placement of the dateline is somewhere in the Pacific Ocean, then at the time of Matan Torah the question wasn't relevant to any Jew, and by the time it did become relevant the technology was already in place.
    Furthermore , even if one is to assume that the dateline is precisely 90 degrees east of Yerushalayim - there is still no necessity to measure it exactly. A person who finds himself approximately in that vicinity would have to be stringent and observe 2 days for Shabbos.


    1) "Since the world is round there must be a dateline. Anyone who says otherwise doesn't understand the nature of the dateline. The only question is where it is?". Yet, I quoted above authorities who explicitly said that there is no dateline. Are you forced to say they were ignorant of the problem? Maybe there is another explanation.

    The answer lies in the fact that while it is true that as you travel east from Israel, you eventually reach a place which is a day behind you (e.g. New York), that doesn't mean that the Torah determined that via a line given down to Moshe Rabbeinu. Another possibility is that the Sabbath observant people (or perhaps the Gentiles who use a 7 day week) who settled New York came traveled in a Western Direction. Thus they established the local count for that location based on the number of sunsets that they experienced. In that case, there is no "line" pre-established, but rather you can draw a continuous curve, after the fact that, cuts from the North pole to the South pole (or at least from Arctic to Antaractic cirles).

    That said, I think that your reasoning is one of the main assumptions (imo, faulty) that underlies many of the arguments that there the Torah must have determined a datelline.

    2) Regarding his question - How is the man of Matan Torah supposed to measure it - If the Chazon Ish is correct that the Asian coastline is the dateline then no sophisticated measurements are needed.

    You need to look at his dateline. If there were no large populated islands in the Pacific, then you might be right, but there are. For example Australia is to the west of the "line" and Japan to the east. All of this can be calculated only with cartography not available in ancient times.

    Furthermore , even if one is to assume that the dateline is precisely 90 degrees east of Yerushalayim - there is still no necessity to measure it exactly. A person who finds himself approximately in that vicinity would have to be stringent and observe 2 days for Shabbos.

    In ancient times, there was really no way to know when you were anywhere near that line. I'm also not sure that the fact that you can go "L'Chumra" makes a difference. You still end up with halacha based on something that they had no way to determine, which is against the general principle that the Torah was given to man and not to the ministering angels.

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  31. David - just wanted to point out that this "6+1" theory that you keep attributing to the "no-dateline" poskim is really a meaningless term and quite misleading as well. EVERY single posek who discusses the dateline as well as every single first grader who ever listened to big gedalya goomber understands and agrees that shabbos is determined by 6+1. That is UNTIL 6+1 no longer works (which of course what the dateline question is all about) - either running into an imaginary line on the globe disrupts your count or running into another city with a pre-established minhag that differs from your count disrupts it. Either way - its a question that needs to be addressed and "minhag" doesnt really cut it when the safek exists on 25% of the globe and when only 3% of that area is covered by some sort of minhag. You dismiss the questions of all other areas or boat travel or people meeting somewhere in an uninhabited spot on the globe but coming from different directions as "edge" cases - but they are not 'edge" cases at all in regards to the dateline question...............they ARE the dateline question. It would be like someone posing a question of what happens when a little milk falls into chicken soup and getting back three answers. The first guy says its batul in 60. The second guy says its batul in 90. And the third guy says lets face it - Chazal knew nothing about meat. Chazal knew nothing about milk - so there is really no halacha that addresses your question. And by the way, milk falling into meat is an "edge" case. You should really be keeping your meat and milk separately.

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  32. David - just wanted to point out that this "6+1" theory that you keep attributing to the "no-dateline" poskim is really a meaningless term and quite misleading as well.

    Yet, Rav Zvi Pesach writes the following:

    there is no foundation in the Talmud or later authorities that there exists a dateline; this itself is a clear proof that, in fact, the date is not established by the Torah, because [otherwise] how could the Torah be missing such a [important] principle which is relevant to the establishment of Shabbos. Rather, perforce, [the halacha is] in accordance with that which the Radvaz wrote, that the Mitzvah of Shabbos is such that in each place one works six days and rests on the seventh day, in accordance with the plain language of the Torah in all places [in the Torah] where the Torah prohibits [work on] Shabbos. Once should not deviate from this [principle].

    So it is not me attributing it.

    EVERY single posek who discusses the dateline as well as every single first grader who ever listened to big gedalya goomber understands and agrees that shabbos is determined by 6+1. That is UNTIL 6+1 no longer works (which of course what the dateline question is all about) - either running into an imaginary line on the globe disrupts your count...

    This is an argument for the no-Torah-determined-dateline position. If you don't have that, then there is no imaginary line and the people going East from China do what almost all the Rishonim say: start from the East.

    or running into another city with a pre-established minhag that differs from your count disrupts it.

    So then you go with the existing minhag. You can create this problem without the dateline by Antarctica in the winter or summer. Or you can travel around the world in one direction until you get back to where you started from. That doesn't prove that the Torah established a dateline.

    Either way - its a question that needs to be addressed and "minhag" doesnt really cut it when the safek exists on 25% of the globe and when only 3% of that area is covered by some sort of minhag.

    I'm missing where the 25% and 3% come from. Can you clarify?

    You dismiss the questions of all other areas or boat travel or people meeting somewhere in an uninhabited spot on the globe but coming from different directions as "edge" cases - but they are not 'edge" cases at all in regards to the dateline question...............they ARE the dateline question.

    I'm dismissing this as a proof that the Torah determined a dateline and if you look hard enough, you will find it. The indeterminacy argument is much worse for those who hold of a dateline: the Torah left out where it is and there is no one agreed place where it must exist. This is actually Rav Tzvi Pesach's argument.

    It would be like someone posing a question of what happens when a little milk falls into chicken soup and getting back three answers. The first guy says its batul in 60. The second guy says its batul in 90. And the third guy says lets face it - Chazal knew nothing about meat. Chazal knew nothing about milk - so there is really no halacha that addresses your question. And by the way, milk falling into meat is an "edge" case. You should really be keeping your meat and milk separately.

    I'm not following this argument. Can you clarify?







    ReplyDelete
  33. David - just wanted to point out that this "6+1" theory that you keep attributing to the "no-dateline" poskim is really a meaningless term and quite misleading as well.

    Yet, Rav Zvi Pesach writes the following:

    there ……………. Once should not deviate from this [principle].

    So it is not me attributing it.
    I realized that it wasn’t you attributing it. I was just pointing out that I don’t understand how it contributes anything to the dateline discussion and hoped that you would be able to explain how it does since you seem to advocate that approach.

    EVERY single posek who discusses the dateline as well as every single first grader who ever listened to big gedalya goomber understands and agrees that shabbos is determined by 6+1. That is UNTIL 6+1 no longer works (which of course what the dateline question is all about) - either running into an imaginary line on the globe disrupts your count...

    This is an argument for the no-Torah-determined-dateline position. If you don't have that, then there is no imaginary line and the people going East from China do what almost all the Rishonim say: start from the East.
    I thought that almost all the rishonim say like the chazon ish. Are there any that advocate a no-dateline approach?

    or running into another city with a pre-established minhag that differs from your count disrupts it.

    So then you go with the existing minhag. You can create this problem without the dateline by Antarctica in the winter or summer. Or you can travel around the world in one direction until you get back to where you started from. That doesn't prove that the Torah established a dateline.
    I think it does and seem s to be a much more logical approach than saying that a machlokes as to where the dateline is proves it doesn’t exist. Try starting from the opposite angle of what you keep saying. The torah prescribes sekila as an onesh for one who desecrates Shabbos bmeizid. But yet the torah doesn’t define what Shabbos is?? How does that make sense? The dateline poskim both understand that the torah defines it quite precisely (with a dateline), although they differ as to where that line is. But there are hundreds of such machlokes throughout shas. Beis Shammai & Beis Hillel had disagreements in yevamos with one saying something was a mitzvah dioraissa and the other saying that it was an issur kares. Is that a proof that the torah didn’t have an opinion on the matter?

    Either way - its a question that needs to be addressed and "minhag" doesnt really cut it when the safek exists on 25% of the globe and when only 3% of that area is covered by some sort of minhag.

    I'm missing where the 25% and 3% come from. Can you clarify?

    What I am saying is that there is no dateline consensus on 25% of the globe (the entire distance between 90-180 degrees east of Jerusalem) and yet many many cities in that rather large section of the globe do not currently have existing jewish communities which are koveah ANYTHING. I assume that you don’t suggest that a single community in an entire country is what is kovea minhag for the whole country? When it comes to other minhagim (like a ben eretz yisroel in chu”l on yom tov sheini or any other minhag that would require one to accept chumrei hamakom) , we use techum Shabbos to be kovea. 3% is just a rough guesstimate but I am sure that you would agree that the vast amount of cities within that section of the globe have no existing minhag. So the question remains: On which day does one celebrate Shabbos? And if there is no dateline, than we aren’t really limited to that part of the globe at all – even if you keep going in the same direction and then “land” in an uninhabited area, why would you change your 6+1 count?

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  34. I'm dismissing this as a proof that the Torah determined a dateline and if you look hard enough, you will find it. The indeterminacy argument is much worse for those who hold of a dateline: the Torah left out where it is and there is no one agreed place where it must exist. This is actually Rav Tzvi Pesach's argument.
    This paragraph really makes no sense at all. How is the position of those who hold of a dateline indeterminate at all? They are extremely precise and leave no case to guesswork. All poskim who advocate for it, don’t have any doubts that there is a source for where it is and they feel that that is the place it must exist. A machlokes or lack of consensus about something proves nothing – there are thousands of them throughout shas. R Moshe Feinstein says that using liquid soap on Shabbos is an issur dioraissa – yet many poskim permit it. How can R Moshe feel that the torah makes something assur without EVERYONE agreeing to him? Without there being an undisputed consensus that the torah has a clear valid source for prohibiting it? It happens all the time

    It would be like someone posing a question of what happens when a little milk falls into chicken soup …….. is an "edge" case. You should really be keeping your meat and milk separately.

    I'm not following this argument. Can you clarify?
    See the very short summary that Rabbi Slifkin posts all the way at the very beginning of his first post on the matter. He breaks the shittos down into 3 groups – 90 degrees, 180 degrees, and NO DATELINE. He makes it clear that he “prefers” the third one – even claiming that it falls under his definition of rationalist. Many readers (including myself) took issue with that categorization, but I am taking it a step further. I don’t really understand what the position is at all. Is it accepting the secular line? My understanding was that only Rav Menachem kasher went with that and even he was suggesting it as a way to build an arbitrary consensus since he felt there was no great source. Maybe had everyone indeed accepted it, it would make sense, but since there seems to be a machlokes anyway – its hard to see why the secular line has an advantage over the two that at least have sources (flimsy as they may be). If you bet on one of those, at least your odds are 50/50.
    Since that original posting, it seems like you have been saying that there is some sort of 4th shitta which you call the “6+1” count. I do not understand what that shitta says to do when there is no existing minhag.
    Last, but not least, do you have some sort of basic breakdown of what the shittos are and which poskim weigh in with which ones. I for one would love a chart format……..

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  35. I'm dismissing this as a proof that the Torah determined a dateline and if you look hard enough, you will find it. The indeterminacy argument is much worse for those who hold of a dateline: the Torah left out where it is and there is no one agreed place where it must exist. This is actually Rav Tzvi Pesach's argument.
    This paragraph really makes no sense at all. How is the position of those who hold of a dateline indeterminate at all? They are extremely precise and leave no case to guesswork. All poskim who advocate for it, don’t have any doubts that there is a source for where it is and they feel that that is the place it must exist. A machlokes or lack of consensus about something proves nothing – there are thousands of them throughout shas. R Moshe Feinstein says that using liquid soap on Shabbos is an issur dioraissa – yet many poskim permit it. How can R Moshe feel that the torah makes something assur without EVERYONE agreeing to him? Without there being an undisputed consensus that the torah has a clear valid source for prohibiting it? It happens all the time

    It would be like someone posing a question of what happens when a little milk falls into chicken soup …….. is an "edge" case. You should really be keeping your meat and milk separately.

    I'm not following this argument. Can you clarify?
    See the very short summary that Rabbi Slifkin posts all the way at the very beginning of his first post on the matter. He breaks the shittos down into 3 groups – 90 degrees, 180 degrees, and NO DATELINE. He makes it clear that he “prefers” the third one – even claiming that it falls under his definition of rationalist. Many readers (including myself) took issue with that categorization, but I am taking it a step further. I don’t really understand what the position is at all. Is it accepting the secular line? My understanding was that only Rav Menachem kasher went with that and even he was suggesting it as a way to build an arbitrary consensus since he felt there was no great source. Maybe had everyone indeed accepted it, it would make sense, but since there seems to be a machlokes anyway – its hard to see why the secular line has an advantage over the two that at least have sources (flimsy as they may be). If you bet on one of those, at least your odds are 50/50.
    Since that original posting, it seems like you have been saying that there is some sort of 4th shitta which you call the “6+1” count. I do not understand what that shitta says to do when there is no existing minhag.
    Last, but not least, do you have some sort of basic breakdown of what the shittos are and which poskim weigh in with which ones. I for one would love a chart format……..

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  36. I realized that it wasn’t you attributing it. I was just pointing out that I don’t understand how it contributes anything to the dateline discussion and hoped that you would be able to explain how it does since you seem to advocate that approach.

    Let me state try to state it very simply. A person travels east and gets to Japan. He naturally celebrates Shabbos on Saturday both because everyone thinks that its Saturday and because that the seventh sunset since the last Shabbos. The someone comes and says: wait you crossed a line and you should have gone back in time one day. I know that you won't find this mention of this line or the need to move the day back in the Gemara or any Poskim, but trust me, it's there. Ignore what everyone else is doing and celebrate Shabbos on Sunday; they are all unwittingly descrecrating Shabbos . There is a high bar of proof needed her before we believe this person (and obviously the stature of the Chazon Ish is something that help meet that bar).

    This is an argument for the no-Torah-determined-dateline position. If you don't have that, then there is no imaginary line and the people going East from China do what almost all the Rishonim say: start from the East.

    I thought that almost all the rishonim say like the chazon ish. Are there any that advocate a no-dateline approach?

    The Chazon Ish makes the claim, I believe, that all Rishonim who speak about the topic put the dateline where he interprets it to be (or approximately so; I need to complete my study of all of the Chazon Ish material that I have). I'm asserting that this is a highly unlikely interpretation.

    The Yesod Olam says that the day starts in the East. He believe that there was no habitation in the Western Hemisphere. Thus

    1) He did not need a dateline. The day started in the extreme East and ended in the extreme West. The fact that such extremes don't exist in the real world was not known to him.

    2) If you would have shown him a map of the Eastern Hemisphere and asked him whether the end of the "East" includes Japan, he would have undoubtedly have said yes.

    Even the Kuzari doesn't align well with the Chazon Ish. Kuzari says explicitly that China is 18 hours ahead of Israel. Chazon Ish interprets that as a theoretical point at the edge of China, but that is not apparent from the Kuzari itself.

    What I am saying is that there is no dateline consensus on 25% of the globe (the entire distance between 90-180 degrees east of Jerusalem) and yet many many cities in that rather large section of the globe do not currently have existing jewish communities which are koveah ANYTHING.

    First off that 25% of the globe is mostly uninhabited. Aside from people that are Choshesh for Chazon Ish, there is very little doubt as to which day is Shabbos in most places.

    But let me try to unravel what I believe is your argument. If you assign a dateline, any dateline, then you remove all uncertainty. And since the Torah doesn't make things uncertain, there must be a dateline.

    1) I don't agree with the premise. There are always new cases not covered by the existing rules. The fact that one rule covers more cases doesn't make it more right. The discovery of worldwide habitation and the technology for worldwide travel are new. It is very likely that innovation is required to cover these cases.

    2) Even with a dateline, you have uncertainty at the poles, in orbit, in the center of the earth, on the moon, what to do when crossing the dateline etc.

    3) From a practical perspective the Chazon Ish dateline caused tremendous uncertainty, which Rav Tukachinski much laments in is sefer. He went so far as to suggest that R. Herzog's Beis Din not respond to the telegram from Kobe once the Chazon Ish had already done so because he did not want to risk anyone fasting on Y"K two days, even though he thought that the Chazon Ish was mistaken.

    4) There certainty is all hypthetical. Since there are "n" datelines, no certainty is achieved.

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    1. Correction:

      Even the Kuzari doesn't align well with the Chazon Ish. Kuzari says explicitly that China is 18 hours behind Israel.

      Delete
  37. I'm dismissing this as a proof that the Torah determined a dateline and if you look hard enough, you will find it. The indeterminacy argument is much worse for those who hold of a dateline: the Torah left out where it is and there is no one agreed place where it must exist. This is actually Rav Tzvi Pesach's argument.
    This paragraph really makes no sense at all. How is the position of those who hold of a dateline indeterminate at all? They are extremely precise and leave no case to guesswork. All poskim who advocate for it, don’t have any doubts that there is a source for where it is and they feel that that is the place it must exist.

    I think that I explained it above. I'll add in one of Rav Tukachinski's argument which I think aligns with Rav Frank: in order to upset the existing minhag, one need stronger proof for the certainty of the 90* dateline. Without that, better to leave things as they are.

    See the very short summary that Rabbi Slifkin posts all the way at the very beginning of his first post on the matter. He breaks the shittos down into 3 groups – 90 degrees, 180 degrees, and NO DATELINE. He makes it clear that he “prefers” the third one – even claiming that it falls under his definition of rationalist. Many readers (including myself) took issue with that categorization, but I am taking it a step further. I don’t really understand what the position is at all.

    It means exactly what the words say: That the Torah did not draw a line. Rather the line (or reallyu a curve or sequence of line segments) emerges out of people's behavior and decisions using the 6+1 rule and adherence to existing Minhag. Had human history or the configuration of land in the pacific been different, the line might be different.

    Is it accepting the secular line?

    Not necessarily, although that seems to be the Minhag Haolam (which has weight) and it is consistent with the other principles. My understanging of Rav Kasher (and I have to get his book) is that the halacha doesn't have a rule for all cases built in, so a certain amount is left in the hands of the Rabbis to decide and thus they should just all agree use the secular dateline for borderline cases. Until that time, there is some uncertainty in some places.

    Maybe had everyone indeed accepted it, it would make sense, but since there seems to be a machlokes anyway – its hard to see why the secular line has an advantage over the two that at least have sources (flimsy as they may be). If you bet on one of those, at least your odds are 50/50.

    The advantage of the secular dateline is that it conforms with the 6+1 rule and existing Minhag rule. the other "lines" create conflict (although the "mid pacific" poskim are pretty close).

    Since that original posting, it seems like you have been saying that there is some sort of 4th shitta which you call the “6+1” count.

    The 6+1 shita is not a fourth Shita, it is part a natural outgrowth of there being no line, as Rav Tzvi Pesach says explicitly.

    I do not understand what that shitta says to do when there is no existing minhag.

    It says that when Japan was settled by Jews, they should keep Shabbos on Saturday, since they did not cross any halachic line.

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    1. Thank you for all your informative commentary. I realize I don't have the Torah knowledge or sources to convince anyone here, but I think your point (that there can be no halachic definition of a dateline) makes perfect sense.

      Going a little further, using just logic, it would seem to me that in the ancient world (or maybe even only a few hundred years ago), you would have no way of knowing when any dateline would be crossed, unless it was defined as the coast of a continent or some similarly recognizable landmass.

      As such, someone traveling without contact with the rest of the world would have no choice but to determine Shabbos by counting sunsets. The issue of a dateline would only come into play when the traveler arrives at an established Jewish community somewhere and realizes that his Shabbos isn't the same as theirs. Only then would he know enough to realize that he must have crossed a dateline, and he would therefore only change his understanding at that point.

      Furthermore, it would seem that there could be a theoretical situation where two communities in the same or similar longitude might observe Shabbos on two different days, if the original travelers arriving at those communities arrived from different directions (one going west, one going east) and that the Torah would not be able to conclusively declare one right and the other wrong.

      It is only in the modern world, where we have very accurate navigation equipment, and where one is never truly out of contact with any community (at least any that has a telephone) that it would even make sense to talk about a dateline. And if we would want the decision to be compatible with what would have to take place in the ancient world, it would mean Shabbos would be observed when the nearest Jewish community observes it, which would place the hypothetical dateline (for the most part) where the rest of the world has agreed to place it.

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  38. I see a basic problem for those who appear to base their consideration of a date line on the Ba'al Hama'or's (BH) commentary on the Rif (Rav Yitzchak Alfasi) on Rosh Hashana (RH). That lengthy commentary is at the end of the 1st perek of RH, cv. 'ki salik R' Zeira'. It is rather removed from a simple understanding of RH 20b (see Rashi there for the more evident understanding), and appears to be motivated by the unreality of the times of new crescent and final old crescent sightings relative to the calculated mean lunar conjunction (Molad). The statement in that gemara is that the new moon is visible 6 hours after the Molad in Israel, while the old crescent was last visible 18 hours before the Molad. In Bavel, the times are reversed. The problem is that 6 hours is much too soon after the true lunar conjunction (calendar new moon) for the new crescent to be visible just after sundown (unless the calculated Molad is some 12 hours after the actual conjunction). Both the Rambam in M.T., Hilchot Kiddush Hachodesh (1:3) and the BH in his Rif commentary state that the new crescent is first visible 24 hours after the Molad. Moreover, the statement in the gemara that there is a 24 hour period when the moon is invisible is not accepted by the Rambam (or by implication in the BH) who states that the period of invisibility is about 2 days. Rather than rejecting such statements in the Talmud as being inconsistent with actual observations, the BH creates a new scenario for the gemara wherein the focus is on the eastern edge of habitation (supposedly 90 degrees east of J'lem), and the day count starts with J'lem time. The eastern end is therefore 18 hours behind J'lem time (JT) rather than 6 hours ahead. He uses this scenario in a rather complicated and seemingly odd way to explicate the statements in the gemara. Among others, he assumes that when the Babylonian Amora refers to 'us', he really means someone living at the eastern end of the habited world. The main problem, however, for using this 90 degree line as a date line is that the BH doesn't do so. He simply states that it is 18 hours behind JT rather than 6 hrs ahead of it. In his westward advance of the sun from J'lem scenario, the lag time of places further and further west doesn't end at the 90 degree line. Rather, logic would dictate that it continue until there is a 24 hour lag. That 24 hour line is just east of J'lem (or Israel) following the BH scenario. That would mean that the Jews in Bavel and Israel (Judea/Palestine) had a different day count. There is no such difference that I am aware of, nor does the BH bring such a source which, if found, would be a powerful confirmation of his ideas. As it stands, it appears to be a powerful argument against the BH and those who would use a 90 degree date line. If the latter can't really use the BH as a source, then that line is merely conjecture with no halachic support in the talmud.

    Y. Aharon

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    1. The problem is that 6 hours is much too soon after the true lunar conjunction (calendar new moon) for the new crescent to be visible just after sundown (unless the calculated Molad is some 12 hours after the actual conjunction).
      ...
      I suspect that you and R. slifkin will not approve of the answer here but here it is.
      http://www.mail-archive.com/daf-discuss%40shemayisrael.co.il/msg03184.html

      Dr. Nissim Vidal (formerly of the Royal Observatory at Greenwich) discusses
      this point at length in his "Kuntrus 24 Sha'ot". He cites the Maharal
      (Be'er ha'Golah ch. 6) who discusses this point in detail and concludes
      that Moshe received a prophetic vision that the physical limit for sighting
      the moon under *any* condition is 6 hours away from the sun.

      Dr. Vidal points out that the current world record (~2007) was 14 hours by
      the unaided eye and 12 hours with a telescope - but it is constantly
      changing. We cannot put a physical *lower* limit on the sighting, only an
      *upper* limit. In order to disqualify witnesses, we need a physical lower
      limit - and for that we must rely on the prophetic limit that we received
      from Moshe mi'Sinai.

      Interestingly, Dr. Vidal brings citations (found in Emunas Chachamim, by
      Rav Avi'ad Sar Shalom Bazilia) from Johannes Kepler and the Roman
      astronomer Pliny to the effect that the old moon and the new moon can
      indeed be sighted on the same day - morning and evening (i.e. less that 7-8
      hours from the Molad on either side)! Emunas Chachamim adds that he advised
      with two of the greatest astronomers of his generation, in Bologna, Italy,
      as to whether this phenomemon was true of the latitude of Jerusalem as
      well, and they agreed that it was.

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    2. Dr. Vidal points out that the current world record (~2007) was 14 hours by
      the unaided eye and 12 hours with a telescope - but it is constantly
      changing. We cannot put a physical *lower* limit on the sighting, only an
      *upper* limit. In order to disqualify witnesses, we need a physical lower
      limit - and for that we must rely on the prophetic limit that we received
      from Moshe mi'Sinai.


      This is all very nice, but with respect to Halacha, the Rambam disagreed. He wrote up the conditions for visibility based on his understanding at the time and he knew that it was much more than 6 hours. He says that the Beis Din needed to calculate when it might really be visible and disqualify witnesses on that basis. Understand that the new moon can be very hard to see, and people have done tests and show that an average person today will think he/she can see the moon when it is not possible (perhaps in ancient times, when people studied the sky more, they would be more careful, but false positives were definitely possible).

      Anyhow a lower limit can be established by testing and by theory as well and six hours is way too short.

      If Kepler said it he was mistaken, but I'd like to see where he said it.

      [Added later:] I see know that the author of the post there mentioned that the Rambam disagreed. I would also point out that Chatzos can refer to the night, so it is possible the the Gemara actually meant 18 hours, not 6, which might be one of the Rambam's sources as well.

      Delete
    3. I see a here reference to the Kepler story as a legend:

      http://books.google.com/books?id=5Ojmbu_a4mkC&pg=PA26&lpg=PA26&dq=kepler+new+and+old+moon+same+day&source=bl&ots=ji_3tDxFaF&sig=XaYerf2LYxIXNKdAXoeZXytmVJ4&hl=en&sa=X&ei=Gd4aVMOCLLeJsQSJwYHABQ&ved=0CDkQ6AEwAw#v=onepage&q=kepler%20new%20and%20old%20moon%20same%20day&f=false.

      Also, Kepler suffered from myopia and I have heard in a lecture that he couldn't see the sky well until the invention of the telescope. So the story is even more suspect.

      Delete
  39. levi, You're correct, I am not impressed with Rabbi Kornfeld's answer or his citations. The questioner had a very legitimate objection (he phrased it more delicately) to the gemara's statement about the time of last visibility of the old crescent (the 18 hours is presumably after sunset) and the new crescent (the 18 hours is presumably before sunrise). However the crescent moons are not visible under those conditions since the old crescent leads the sun in rise/set, while the new crescent lags. Rabbi Kornfeld attempts to understand the gemara in a simple way (much like Rashi) without the benefit of astronomical reality. However, the apparent conflict between statements in the gemara and observations is what lead the Rambam in Hilchot Kiddush Hachodesh to reject that gemara's understanding and to rely on observed data. It also,.apparently, motivated the Ba'al Hama'or to offer an explanation of the gemara that is far removed from the evident peshat. The issue of the minimum interval between the molad and the last visibility of the old crescent or the first visibility of the new crescent is complicated by the variable difference between the molad calculation based on a constant lunar period and modern calculations of the actual lunar conjunction (labeled new moon in calendars). The interval between the last and first sightings is more straightforward. T.B. Rosh Hashana, 20b accepts that there is a 24 hour difference, the Rambam states that it is about 2 days, while Dr. Vidal cites statements that they can even be seen the same day. Well, the latter citation also disagrees with the gemara as well as more modern data. If the objective is to justify the gemara, how does such a citation accomplish it?
    Y. Aharon

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  40. Too bad this post and the prior one on the date line and halacha are off the 'front page'. They and their comments serve as an excellent example of a rationalist vs non-rationalist approach to halachic and ideological matters. Not only won't leading proponents of the various artificial date lines accept the view of Rav Zvi Pesach Frank, Rav Isser Zalman Melzer, and, presumably, Rav Yitzchok Herzog that there is no halachic date line, but their view is not even mentioned (see article on the date line by a Star-K rabbi) - or is dismissed as an idiosyncratic view of an individual scholar. Well, we rationalist types can do the same. If I should ever find myself in Hawaii, Japan, New Zealand and other such 'problematic' places with Jewish communities, I fully intend to observe Shabbat only on the day accepted as such by the people there, without any compunction to do biblical work on Friday (Hawaii) or Sunday (Japan or New Zealand).

    In the meantime, let everyone have a good, healthy, and enlightened year.

    Y. Aharon

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