One of the reasons it’s so hard for me to accept materialism is that I don’t exactly know how matter is supposed to be defined without at least some circularity or question-begging. It is probably a caricature to think that materialist philosophers all believe that matter is just little billiard balls bouncing into each other, because nowadays we know that there are also fields and forces at work, that energy and mass can be interchanged, and that the little billiard balls are actually clouds of probability. I am guessing that modern materialist philosophers, and quantum physicists, acknowledge this and talk about matter with more qualifications. In the realm of macro-physics and chemistry, the billiard ball analogy is sufficient, though I’m sure these physicists and chemists are aware that matter isn’t actually like this.
On the other hand, I would say that in the other sciences, like psychology, biology, and neuroscience, where scientists don’t deal directly with the nature of matter, the conception of matter as billiard balls is very much the dominant paradigm, and these scientists are unaware of any qualifications. It is just taken as a given that matter can be reduced to billiard balls – or “pebbles in a box” as Imants Baruss says. This is understandable because it is a model that works well in a general way. Except when I started my training as an experimental psychologist, I got this sinking feeling that talking about motivation, qualia, and intentionality is actually extremely problematic if matter is simply billiard balls. I’ve read quite a bit of materialist philosophy that has been written over the last century and it doesn’t seem like any of them can resolve the problem at all. As a result, I began to doubt strict materialism.
So for me to believe in any sort of materialism, I would have to come across a formulation that gives matter properties that can take matter beyond itself (like when I’m thinking of my grandmother in Kentucky), and it’s hard for me to conceive of these extended properties as anything other than immaterial (because they are not matter). To me, the only way to make sense of matter going beyond itself is final causality, which brings me back time and time again to Aristotelianism.