Well, you can say that there's no such thing as colour from a materialistic viewpoint, but there certainly is such a thing as the impression in our minds that "certain wavelengths of light" make. That's expressing things in the usual materialistic terminology; however, that reflects the materialistic paradigm that everything is caused by interaction of particles and forces, and that is the very point that I as an idealist would challenge.
To my mind, particles and forces have no reality: they're just useful models. The real causality doesn't reside in particles and forces, but in processes occurring in universal consciousness which happen to present an appearance to perception of something we can model as particles and forces.
To my mind, particles and forces have no reality: they're just useful models. The real causality doesn't reside in particles and forces, but in processes occurring in universal consciousness which happen to present an appearance to perception of something we can model as particles and forces.
I don't agree with what you say here: We filter these wavelengths of light through our retinae and subsequent visual pathways to represent colour, but these colours (or qualia) are illusions." Again, that is based on a materialistic viewpoint, on accepting models of reality as actual reality. As a matter of fact, the only things we perceive are qualia: everything else is an interpretative model. It is the qualia that are nearest the real: if they're illusions, then all of science is an illusion since it is based on the qualia we empirically observe. I believe it's rather the case that what's unreal are the models which physicalism reifies and arbitrarily gives precedence over qualia.
This is a conceptual trap, which materialists have the greatest difficulty avoiding; having constructed what are, after all, only models of reality, they then argue their case based on the assumed concrete reality of those models -- and that's a form of circular reasoning.
Here's a simple test for an Idealist, qualia as fundamental, model. Under that model we have, as often quoted, "the redness of red"; it is an experience, a fundamental of shared consciousness. Now an idealist would deny that the red experience comes from an interaction with external wavelengths of light (indeed, you have just done this). Yet we have significant individuals who suffer from deuteranopia, and do not "experience" redness to any degree, if at all in extreme cases. It's curious that a fundamental component of shared experience looks less fundamental and less shared than we might have expected. We also have solid detailed biological and histological explanations of how these anomalies occur and it involves the direct interaction between wavelengths of light interacting with central nervous system cells.
Sure, we can come up with all sorts of explanations that may or may not model a situation well, but the fact is, no physical model of the universe is completely consistent, one of the most egregious examples being the fundamental inconsistency of general relativity and quantum theory. You may get a stack of physicists a mile high swearing that one or the other is correct, but none of them can say both are correct, and to my mind that tells me there's something wrong with physicalist interpretations of the world. Quite possibly, both GR and QT as currently understood are incorrect, albeit good enough for purposes of modelling working technologies.