A. Commentary to the Mishnah
Miracles are all preprogrammed into nature since creation
B. Guide to the Perplexed
1. Rambam professes his own view: Miracles are supernatural, and all are possible, as an essential parallel to creation
2. Praises sages’ view that miracles are built into nature
3. Extensively reinterprets many Biblical events so as to remove supernatural aspects
C. Treatise On Resurrection
1. Presents policy of only accepting supernatural as last resort
2. Categorizes some miracles as supernatural and others as natural
D. Epistle Against Galen
Explains supernatural miracles as being relatively minor modifications of nature
Many have tried to make sense out of all these statements, with differing results. See, for example, Joseph Heller, “Maimonides’ Theory of Miracles”; Hannah Kasher, “Biblical Miracles and the Universality of Natural Laws: Maimonides’ Three Methods of Harmonization”; Haim Kreisel, “Miracles in Medieval Jewish Philosophy”; Y. Tzvi Langermann, “Maimonides and Miracles: The Growth of a (Dis)Belief”; Alvin J. Reines, “Maimonides’ Concept of Miracles”; and Michael Tzvi Nahorai, “The Problem of Miracles for Maimonides.” I also have my own paper on it, which is still unpublished.
In this post, I merely wish to draw attention to Rambam's statements about manna. In the Epistle Against Galen, he describes one type of supernatural miracle as being the acquisition of new properties:
Something is innovated which is not in the nature of the present reality to come into existence, such as the entire innovation of the manna, which had the property of being hard and could be ground to make bread, but when the sun shone upon it, it became soft and melted.
The manna itself was not supernatural; what was supernatural was that it was a hard substance that turned into a liquid under sunlight. This is, to say the least, an unexpected aspect of the manna to highlight as being miraculous.
In the Guide (III:50), on the other hand, Maimonides describes the miracle of the manna as follows:
Now the greatest of the miracles described in the Law is the stay of the Israelites in the wilderness for forty years, with a supply of manna every day. This wilderness, as described in Scripture, consisted of places "wherein were fiery serpents and scorpions, and drought, where there was no water"; places very remote from cultivated land, and naturally not adapted for the habitation of man... But God knew that in future people might doubt the correctness of the account of these miracles, in the same manner as they doubt the accuracy of other narratives; they might think that the Israelites stayed in the wilderness in a place not far from inhabited land, where it was possible for man to live [in the ordinary way]; that it was like those deserts in which Arabs live at present; or that they dwelt in such places in which they could plow, sow, and reap, or live on some vegetable that was growing there; or that manna constantly comes down in those places as an ordinary natural product; or that there were wells of water in those places. In order to remove all these doubts and to firmly establish the accuracy of the account of these miracles, Scripture enumerates all the stations, so that coming generations may see them, and learn the greatness of the miracle which enabled human beings to live in those places forty years.
Here, Rambam does not say anything about the nature and formation of the manna per se being miraculous, but rather that the miracle was in its being present constantly over forty years. He certainly did not believe that this was a substance created ex nihilo, and apparently did not even believe that there was anything supernatural about its formation per se. Rambam seems to have shared the view found in certain Yemenite Midrashic texts (and see too Ibn Ezra to Shemos 16:13), that manna is essentially a naturally-occurring substance. It was miraculous in it occurring with unnatural properties (according to the Epistle Against Galen) and with constantly fortuitous timing (according to the Guide). (See the extract from Rabbi Nataniel ben Yeshayah, Nûr al-Zalâm, written in 1329, published in Y. Tzvi Langermann, Yemenite Midrash: Philosophical Commentaries on the Torah, pp. 216-217.)
The reason why I mention all this is that the New York Times just published a fascinating article about various foodstuffs thought to be the Biblical manna, which are making a comeback on modern restaurant menus (link, or you can read the reprint, with typically entertaining comments, at Vos Iz Neias). Food for thought!