Is it materialist to assume that there is some objective substrate to the world even though we cannot preceive "things in themselves" with the senses or with extensions of the senses such as telescopes and microscopes? We can safety assume that a bat or an octopus perceives a different world than we do. Which way of perceiving represents "things in themselves" or is closer to representing "things in themselves?"
Does this question even mean anything? Does anyone care?