(I have commented on this in other threads, but I figured that my ponderings on the subject deserved their own thread.)
Most views of reality can be divided into monism, as represented by physicalism and idealism, and dualism, as represented by the likes of substance dualism, property dualism, and Platonic dualism.
However, none of these views seem to really neatly incorporate the view that math forms a realm either more fundamental than matter or equally fundamental to matter, that mathematical constructs are not merely human creations or approximations of an underlying reality, but rather that the underlying reality is implemented in terms of math.
If one has not read it yet, a good piece on this topic is Eugene Wignerâs The Unreasonable Effectiveness of Mathematics in the Natural Sciences. It discusses things such as how on very scanty evidence scientists have made predictions based almost entirely on math that hold perfectly so far as we can tell, not breaking despite our best efforts to find counterexamples (and when they do break, that is only because there is math that even better describes reality, cf. the supersession of Newtonian physics by relativity), and that mathematical concepts that were created by mathematicians simply due to being cute ideas, without any intention of relating to the physical world, then got pressed after the fact by scientists into service to describe the physical. By this, it leads one to the conclusion that math has some kind of special connection with the universe that could not be true if it were only a human approximation of reality or merely a beautiful intellectual toy.
As for the independent existence of math from physical reality, the reason to believe in this is that mathematical ideas hold no matter what physical terms they are expressed in. For instance, the value of pi is the same for all circles, no matter how those circles are expressed in the physical substrate or if they are entirely abstract, having no physical reality in the first place.
If one truly believed in physicalist monism, one would have to explain the above, how math appears to be more than merely a human approximation of physical reality, how math appears to be both independent of physical reality and simultaneously fundamentally underpinning it.
The only way I can see how to reconcile physicalist monism with this is to posit that math is more fundamental than matter, and that our physical reality itself is a mathematical construct, rather than positing math and matter as two separate realms.
Note, however, that while many mathematicians have classically been Platonic dualists, Platonic dualism itself posits that ideal Forms exist outside the physical realm that the physical realm approximates, while here I am making no assumption that ideas like âBeautyâ, âJusticeâ, and âGoodnessâ have any independent basis whatsoever. If anything, these things arise from human existence in the material realm rather than having any basis in the ideal.
Of course, one could limit Platonic dualism so that only things that can be represented in mathematical terms have any reality independent of the physical. This is closer to my position here.
I personally dismiss Cartesian mind-body dualism out of hand, mind you, because to me there is no reason to believe that sentient beings should have any privileged status given the laws of the universe, and because it is clear that the physical impinges on the operation of the mind (e.g. the effect of psychoactive substances) in a way that would be hard to justify if the mind were a fundamentally distinct quantity from the physical body.
So fundamentally I run into two different philosophical positions from which to choose â either a version of monism where physical reality is math itself, or a version of Platonic dualism where the only things that can exist independently of physical reality are things that can be expressed as mathematical constructs of some sort or another. I am not sure which is more valid overall.