There is very little difference between Rambam and Ramban, the two great representatives of the two schools of Judaism, the rational and the mystical, when it comes to defining the goals and objectives of humanity. They both agree that the goal of Torah is to bring about a perfect civilization that knows God. Rambam’s position is discussed in my earlier posts. We read similar ideas in Ramban in Torat Hashem Temimah (Kitvei Ramban Chavel Edition (Heb.) Vol. 1 page 142-143) and in many of his other writings. The difference between these two greats is how one answers the question of where science stops and metaphysics starts. The implications of the answer to this question underlie the great chasm that developed between the Rambam’s rationalism and the Ramban’s Kabbalah.
Rambam maintained a clear delineation between the physical and the spiritual. Spirituality to him had no place in science. If he did not understand something about the physical world, he assumed it was some mechanism that he had not yet understood. He thought that there are things that humans will never understand through systematic research, only through inspiration or intuition, but ultimately the explanation will be physical. Rambam addresses this in several places in his writing, (I know offhand of three but I am sure there are more), and to me the most telling, especially to a contemporary Jew, is the following one in his introduction to Pirush Hamishna. In a discussion about the purpose of the different components of our world, he makes the following statement -
…some things’ purpose is so deep and hidden that it cannot be known except through a vision or intuition [my paraphrase/explanation - the method used in finding hidden things (see Rabbis Kafieh and Sheilat notes in their respective editions)]. Understanding the purpose of those things through scientific inquiry is impossible. For it is impossible for man to inquire and know why nature has produced ants with and without wings, why it produced a critter with many legs and another with less, and what the purpose of this critter or ant is.
The example he brings is an anachronism for a contemporary reader.
Ramban on the other hand explained scientific mysteries by ascribing them to spiritual entities that emanate from the stars and spheres. Where Rambam saw only unknown physical phenomena, what we now know is gravity, magnetism etc… Ramban saw transitional semi-physical entities that carried out the wishes of the astral powers. In his world, there was no clear delineation between the physical and the metaphysical. There is a category of semi transcendence populated by a multitude of entities such as Sheidim, Ruchot (spirits) and Neshamot (souls) which are found in Tanach and the Gemara. Where Rambam saw allegories and metaphors, Ramban saw science and reality. For a thorough discussion of the contrast between these two thinkers in this area see R. Buchman’s article in Hakirah Vol. 2 http://hakirah.org/Vol%202%20Buchman.pdf .
Ramban could therefore accept many Chazal and verses in the Torah literally. An angel was not just a “form” but also a physical entity albeit ethereal. The soul is similarly a physical entity that God “blows” into man just as the Passuk says. When the rabbis say that there are a finite number of souls stored in the “Guf” created at the same time as the world, he sees that as literal (Kitvei Haramban page 159). That being the case souls must be recycled and a whole body of theories regarding Gilgulim comes into existence. Ramban has support for these ideas from old Midrashim, the Heichalot, and literal reading of more accepted sources. This approach leads to a completely different understanding of Olam Haba, Techyat Hametim and generally has a much more eschatological view of death and its aftermath.
There is no question that some earlier thinkers including some Amoraim and probably Tannaim, held similar positions and Ramban has a rich tradition to rely on. Rambam knew the same sources and either ignored them or when forced to confront them, either interpreted them allegorically or rejected them. Rambam accepted that the Rabbis had no clear tradition when it came to these issues and based their understanding on how they saw their world. He therefore did not have a problem accepting that there are different schools of thought that contradict each other and when looking at a text one has to see to which group the author belonged. When forming our own opinion on which group to follow we have to evaluate which one fits with our reality and follow the Truth as we see it.
Rambam held that there is a limit to what humans can apprehend. Knowing that limit and not going beyond it is a sine qua non of knowledge and perfection.
“A boundary is undoubtedly set to the human mind which it cannot pass. There are things (beyond that boundary) which are acknowledged to be inaccessible to human understanding, and man does not show any desire to comprehend them, being aware that such knowledge is impossible, and that there are no means of overcoming the difficulty. (MN 1:31)
“If, on the other hand, you attempt to exceed the limit of your intellectual power, or at once to reject things as impossible which have never been proved to be impossible, or which are in fact possible, though their possibility be very remote, then you will be like Elisha Acher. You will not only fail to become perfect, but you will become exceedingly imperfect. Ideas founded on mere imagination will prevail over you. You will incline toward defects, and toward base and degraded habits, on account of the confusion which troubles the mind, and of the dimness of its light, just as weakness of sight causes invalids to see many kinds of unreal images, especially when they have looked for a long time at dazzling or at very minute objects.” (MN1:32)
Contrary to popular belief, Rambam was the more conservative of the two. He set limits to how far we may speculate beyond the physical. Ramban with his world of mysticism was much more daring. It was not that Ramban did not accept the limits to human knowledge but rather, though there was no direct evidence for the existence of a spiritual world, there was a lot of circumstantial evidence supporting it. One has to wonder how much his perspective would have changed when confronted with the empirically proven scientific explanations for the once mysterious phenomena. Would he still maintain that magic and astrology work but may not be used because Jews have to rely on God? Or would he accept Rambam’s position that they are forbidden because they do not work and are false? How would this have affected his understanding of the supernal world?
It is important to understand that the two approaches are mutually exclusive. If one accepts Rambam, one has to follow his position to its rational conclusion. Clearly, what to Ramban was science to Rambam was superstition and forbidden. It brought the transcendental into the physical where it does not belong. I find it an affront to my intelligence when I read some who seemingly seamlessly integrate the two approaches. It is insulting to both of these great truth seekers. The approach would have to be with both to try to update their ideas based on our current knowledge. As I quoted in an earlier post, Rav Kook already implied that this would be a much easier task with Rambam’s rational outlook than with Ramban’s mystical one. As I discuss idolatry, we will have to keep in mind the different ways Rambam and Ramban looked at the world. We will see that even in what seems a Halachik issue, the underlying philosophical thinking affects practical rulings.
 They seem to differ in their respective understanding of Vehalachta Biderachav. That is a subject for a separate analysis.