Note that in Halacha 5, the listing of prohibited thoughts is in areas of metaphysics which cannot be demonstrably proven. It does not list the question of the existence of God because according to Rambam that is demonstrable, as I have shown many times (see label “Existence of God). It is the questions that can never be demonstrated, that we have to accept based on tradition and revelation, which we may not question. One may not question the unity of God, how and where existence came into being, prophecy, and the divinity of Torah because these questions can only be answered through revelatory tradition. However, it does not mean that we should not strive for a better understanding and insight into what these beliefs mean and how they dictate how we think about and deal with our existence. On the contrary, this search for understanding is part of the commandment to love God, for love is commensurate with intimate knowledge.
How are we to define the boundaries that separate physics from metaphysics? As I said earlier, metaphysics deals with matters that can never be demonstrated. As our understanding of science advances, that boundary keeps shifting where physics takes over areas that until now were thought to belong to metaphysics. Some of the issues that Rambam held to belong to metaphysics are now demonstrably explained by science. For example, Rambam had no concept of gravity and therefore could not explain the movement of the heavens through physics. He accepted Aristotelian conjecture that the spheres had a built in urge to perfection which encouraged them to self propel in a perfect movement – the circle. As the four elements we know (fire, air, earth and water), do not have the ability to think, the spheres must therefore be made of a fifth element that is of a higher matter that allows the heavens to think. As humans are composed of the four elements, the coarser elements, they cannot have an as advanced ability to comprehend the abstract as the heavens do. It is based on this that the heavens and how they operate was seen as belonging to metaphysics. Apparently, Rambam had his doubts about the accuracy of this conjecture.
“For as regards the things in the sublunary world, his [Aristotle] explanations are in accordance with facts, and the relation between cause and effect is clearly shown. It can therefore be assumed that everything is the necessary result of the motions and influences of the spheres. But when he treats of the properties of the spheres, he does not clearly show the causal relation, nor does he explain the phenomena in that systematic way which the hypothesis of natural laws would demand.” (MN 2:19)
Of course, we now know that this whole construct was fiction and can be explained through the Newtonian laws of physics. However, the basic questions still remain – who was responsible for it to be as it is? Is God in fact responsible for existence, as we know it? Is God a static force in the universe or was He responsible for willing creation in time? If He willed it, for what purpose did He do so? Does God have a plan for existence or is it all left to chance? The answers to these questions have not changed with all the technological advances and scientific insights and are still based on revelation and revelatory tradition. These questions remain whether the world is 6000 years old or millions and the basic answer does not change either. We may have to tweak the questions and answers a little so that they conform to our new understanding but the underlying thought and concept does not change. With the current understanding of the Big Bang, the question of what was there before remains. We still have to answer how was it triggered? If we now suggest that there was some kind of event based on quantum theory the question still remains what and how was that quantum induced event triggered and how did this quantum based system come into existence? We just pushed the question back up the cause and effect ladder but the question remained.
It is with this in mind that I learn Rambam and his thought. It is why I do not see it as irrelevant. I find that he was the most thought out amongst the Rishonim, the medieval thinkers, when it came to understanding the divide between the physical and metaphysical. I think we can see this clearly when Rambam went against almost all thinkers in his time and considered astrology to be nonsense. He clearly understood that although the heavens think, they do not think for us. They may influence the physical on our world through whatever force (gravity of course was unknown), that force is physical only and has no influence on how human minds act. That was so outside the thinking at the time that even Maimonidean followers in Provence could not accept it. His letter to Montpellier which laid out his thinking on this had no impact whatsoever. Maimonideans like R. Yaakov Anatoly, Nissim of Marseilles, Ralbag and many others held on fiercely to astrology. To them that was pure physics just like astronomy. Even as late as the 18th century, the great Gra could not accept that. He accused Rambam of being too influenced by the Greeks when he denied the spiritual forces exerted by the heavens.
It is this clear outlook that rambam teaches that attracts me to his thought and theology and keeps it fresh even during our fast paced scientific age.