For me, material reality is tied to the notion that the world is consistent and conducive to analytical reasoning, that it functions like a machine. It has components which relate to each other in consistent ways that we can model and understand. The fact that these components are best described by field equations rather than newtonian mechanics is incidental.
The main alternative viewpoint to materialism, dualism, posits some further 'external' influence that acts on the world to account for phenomena we poorly understand like consciousness, and for some people psychic or religious phenomena. I think that's just fuzzy thinking, and I don't even really know what they mean. How can something not 'of the world' interact with the world? Surely 'the world' is everything that can act on or influence each other, right? I'm not sure how else to define it.
I'm pragmatically a materialist, just because I don't find use in speculating about the immaterial (by definition.) But although I thought I was so much smarter than Descartes when I was younger, I still can't figure out why I'm in me and not as much in you, and somehow partially in the computer I'm typing on. That I'm more in my head than in my hands, but I'm in both.
I really have no access to that. I've just taken a couple of extreme positions, and hope that one day somebody can come up with some way to reduce or test them materially, although I accept that I can't even speculate about a way to do it.
One is a panpsychism. The material world exists within a substrate of perspectives, and as material objects pass through them, the perspectives momentarily attach to those objects, and whatever is mechanically connected to them. This happens at an arbitrary rate (depending on the density of the perspective substrate and the relative speed of the material passing through it.) If we call the amount of time that a perspective is located "centrally" enough in a human nervous system to have access to it a "moment," then for a moment, that perspective thinks it is me. This assumes that perspectives are distinct for purposes of explanation, but they don't have to be - maybe an infinite number of perspectives think that they are me at any particular moment, and in the next moment, an entirely different set.
The other is that there's a particular geometry of electromagnetic activity that captures perspectives, and minds happen to conform to that geometry.
I don't think these are any more insightful than "the soul talks to bodies through the pineal gland." I can only hold onto them as more abstract and generalized. There's no material way to tell when you've captured a perspective, and we each only know of the existence of one with certainty. We could be Buddhist and say that the universe is one fragmented confused perspective, or say that we're a bunch of islands; either way, we have no material basis for those beliefs. The only thing we know is that we're not P-Zombies. We don't know that others aren't P-Zombies, just us.
The main alternative viewpoint to materialism, dualism, posits some further 'external' influence that acts on the world to account for phenomena we poorly understand like consciousness, and for some people psychic or religious phenomena. I think that's just fuzzy thinking, and I don't even really know what they mean. How can something not 'of the world' interact with the world? Surely 'the world' is everything that can act on or influence each other, right? I'm not sure how else to define it.