Continuing from part one on "Epistemology Naturalized" (1969), we work further through the text, getting into what this new psychology-rooted epistemology might look like.
Quine remains an empiricist in that he agrees that whatever evidence there is for science must be sensory, and that we learn language through the medium of our senses (i.e. no innate knowledge). However, this doesn't mean that science can be actually deduced from observations. Like, reason itself does not tell us what the scientific method is, which then grounds our scientific observations. There are no a priori, unmovable principles underlying this method, and no guarantee that we're doing it right. Perhaps our current theories are tainting our observations. It's like we're in a boat on the sea and have to repair its planks (carefully! only a few at a time!) while floating instead of resting on the foundation of dry land.
So when we want to know, for instance, how the mind comes up with general concepts based on individual observations, instead of doing that how someone like Locke does, let's actually use the methods of scientific observation at our disposal, which could involve brain scans and/or various experiments designed to figure out what elements come first in this construction. The sort of speculation that philosophers like Locke used about that is useful, but is only a first attempt, to be corrected by the progress of science, rather than something firmly grounded by experience.
As Quine points out, the verificationist attempt to equate linguistic meanings with possible experiences goes back to C.S. Peirce, the founder of pragmatism. For more about this "cat on the mat" example and what conditions make such a sentence true, you might want to check out our interview with Simon Blackburn on truth.
We finish this by going more into Quine's comments on translation and will take a second stab at that in part three for this episode, a supporter-only audio recorded on a separate day that will be released to you next week.
Note that Quine's comment about physical objects being theoretical entities is one of the conclusions of his essay "On What There Is," that we covered in our previous Quine episode.