Why materialists are predominantly materialists

[Angrboda]

Of course it does.  Ideas as a something is opposed to ideas as nothing.  That's taking a position.  Only by contrasting the world of ideas with the world of things do you come up with the notion of "what ideas are."  Relationships among objects is a category of idea but it doesn't explain what an idea is.  Our experience is completely noninformative about the nature of ideas.  The only non-position position about their reality is pure agnosticism.  They could be material.  They could be a substance in and of themselves.  They could be illusions.  By describing them as a substance in and of themselves, you're taking a metaphysical view about them as sure as materialism is.  What's worse, you're defining them as the negation of the material.  That's borrowing the concept of the material in defining the idea.  It's an example of the use of the stolen concept.

It is from sensory experience that people explain things in terms of matter and its operations. From that stance, the materialist reinterprets the original sense data and experience - either trying to force mental properties into a materialist paradigm (making it a kind of substance) or dismissing mental properties as illusions because they don't conform our notions about how matter works. But if our knowledge of matter and how it works originally come from sensory experience then denying the reality of sensory experience undermines the reason that knowledge about matter exists in the first place. To me that sounds self-defeating.

When you put a pencil partially in water, it appears to be bent. Does talking about how what appears to be the case isn't actually the case "undermine" our understanding of the phenomena? Or does it deepen our understanding? In the same way, talking about how our experience is not what it appears does not undermine our knowledge of material interactions. We are talking about how our experiences are derived, instead of actually using our experiences to derive knowledge. That's a sort of use-mention error. If we talk about how there is a blind spot in our visual field, one that we don't "see", we come to a deeper understanding of the reality of our perception, not a lesser one.

"It is from sensory experience that people explain things in terms of matter and its operations." (from above)

I would argue that our sensory experience embeds the quality of object permanence on all our percepts. Just as we can't perceive the world around us as having less than 3 dimensions, we can't perceive objects without them being imbued with a sense of permanance. It is a pre-experience given that things have permanence. This quality of object permanence implicitly contains the idea that things are made of 'stuff'. Even when we imagine the mind of someone else, we imagine it as a thing existing inside that person; we don't attribute the consciousness of a person to their leg or their big toe. There is the image of someone trying to catch a sunbeam. Implicit in that image is the pre-rational thought that the thing--the sunbeam--is made of stuff, and thus can be caught. So it isn't so much that from experience we explain things in terms of matter, but that materialism is a base property of thought. If we talk about how the desk in front of me may really be just a thought in the mind of God, with no object permanence, no material 'stuff', would that undermine our experience of it as 'stuff'? Only in the sense that we are replacing one, pre-rational explanation of the desk with a different one. This is neither lesser nor self-defeating. At bottom, our experience of things, like the pencil in the water, is a theory about how things are. Replacing one theory with a different theory may be a movement into greater realism, rather than lesser.

This is not to say that no one can know anything about ideas. Ideas are that with which we are most intimately familiar. For that reason, I believe they should be treated on their own terms and not forced to fit in some Procrustes bed fabricated by materialist assumptions.

Ideas don't have an "on their own terms" -- as Kant noted, our experience of them comes with a structure already given. That structure, for better or worse, is a theory about ideas. It is likely more Procrustean to try to force them into an abstract space, not structured by the givens of thought. This is not to say we shouldn't entertain the notion of thoughts under some other theory, but that the materialist experience is how we experience ideas "on their own terms." As noted in the previous message, we imagine our thought in a sort of Cartesian theater, existing in space. It's natural that this experience of our minds existing in space comes pre-structured with the same structure as other objects in space, as being composed of 'stuff'. Perhaps it is our pre-rational tendency to attribute object permanence to things made of stuff that explains why we instinctually imagine the mind continuing on after the death of the body. Could this be the source of all our dreams about an afterlife?

...Schopenhauer described transcendental idealism as a "distinction between the phenomenon and the thing in itself, and a recognition that only the phenomenon is accessible to us because "we do not know either ourselves or things as they are in themselves, but merely as they appear."

https://en.wikipedia.org/wiki/Transcendental_idealism