Robert took great exception to my recent post that all facts are "theory laden." He claimed that, when his senses are working properly, if he says "I see an apple," he sees an apple, and that's that.
Scenario: Robert and I are walking in the forest. He says, "Do you see that slug there?" I, an accomplished naturalist, say, "That's not a slug."
"Well," he responds, "it certainly is a very slug-like creature."
"No," I inform him, "that's not even a creature. In fact, it's a collection of slime mold cells, which, generally speaking, live on their own as single-celled organisms, but, when nutrients run short where they are, gather together and crawl to a better place in a slug-like shape." (In fact, they then form something that looks just like a mushroom, a thing that Robert would say "plainly" was a mushroom!)
What we "see" is determined by our theories of what we might see and by our theories of what categories to put those things into. Even Robert's apple judgment could be wrong: It could be a very realistic wax apple, or a new peach genetically engineered to look like an apple. His judgment (for it is a judgment, and not any sort of "direct perception") "that is an apple" is based on a theory that anything that looks like "that" must be an apple.