In Ramban's commentary to Bereishis 2:7, we find the following remarkable paragraph:
Know that of those who investigate philosophical inquiries regarding the components of man, some of them say that man is composed of three souls: a vegetative soul with the power of growth... an (animalistic) soul with the power of motion... and the third is the soul of the rational intellect. And others say that all these three forces are found in the soul that is contained in man from the Mouth of the High One.
In the version of Rambam's commentary that I have on my DBS Torah database, there are parenthetical comments indicating that the first view was held by Ibn Ezra and Rabbeinu Avraham b. Chiyya, and the latter view was held by Rambam. But these were not who Ramban was referring to. In fact, he was referring to an ancient dispute between Plato and Aristotle. Plato’s view was that the human soul is a single indivisible entity, comprised of a vegetative-like power of growth, an animalistic life-force, and a rational intellect. Aristotle, on the other hand, took the position that these three components are distinct; in other words, a human being contains the growth-nature of a plant, the animate life of an animal, with a rational intellect superimposed on top of that.
Ramban proceeds to note that while the simple reading of the pesukim would indicate that Plato's view is correct, Onkelos and Chazal side with the other view, of three souls mixed together (for fascinating reasons that we shall discuss in future posts), and this is the view that Ramban seems to favor.
The aspect that I would like to focus on today is the very nature of the question regarding whether the human soul is tripartite or indivisible. It is a question which affects our reading of the Chumash, and which Rishonim had differing views on. Yet Ramban also notes that this is an ancient dispute in natural philosophy - which would indicate that it can theoretically be resolved via natural philosophy. Note that this is not the only time where Ramban says that natural philosophy can alter our understanding of Chumash; Ramban also relies upon Greek science to reject traditional understandings of the rainbow (see Bereishis 9:12) and Chazal’s understanding of human conception (Vayikra 12:2).
So, the question of whether the human soul is divisible is not only a Torah question, but also a question of natural philosophy. Now, science is certainly a far more powerful method for attaining facts than natural philosophy. It would thus seem that according to Ramban, science would theoretically be able to resolve this question and tell us how to understand the Torah.
To be continued...