E
xperience comes first; theory always follows. We can occasioanlly forget this, especially as language develops and becomes abstracted from its roots. We can then fall into errors of rejecting basic experiences because the real world does not match up with our theoretical expectations.
I will give an example. I once had a conversation with a friend who informed me that touch was impossible; that we have never actually touched anything before. He explained that, in fact, our bodies are made of atoms, which have electron orbital shells, and the charges of these electrons repel the electron shells of the objects we "come into contact with". Therefore, there is always a tiny space between ourselves and other physical objects, and they never touch. I touched him on the shoulder and said "I'm touching you right now," and he replied that, no, it only seemed like I was, but we were still distant. Is he right? Is touch impossible?
The essence of my friend's argument is that "touch" means something akin to "two planes sharing the same points in space", as a mathemetician might describe geometrical objects. Since the psuedo-planes of physical bodies never coincide in this way, he concludes that touch is not something that happens in the real world. The problem is that this is categorically not what touch means. The word "touch" is a name applied to an event observed in the actual world--it is a description of what happens (whatever details that happenstance may turn out to have) when two physical bodies come into contact. If it turns out that electron orbitals are repelling one another's charge at close proximity, then that is what it means to touch. The observable experience happens, and we name it--we fill out the details later.
Confusion can enter into language and reasoning when words start to be appropriated by experts in specific contexts (who typically know their own limits, and do not make these mistakes), then bleed back out, subtly modified, into non-expert communities. The word "touch" starts to take on a geometrical quality, and when mixed with other tidbits of knowledge (like electron orbitals), can lead to errors in which more basic, more certain realities are discarded to maintain theoretical consistency. This temptation must be resisted. Reasoning proceeds from the more certain to the less certain. Our basic experiences, while vague and preliminary, are the building blocks of all our reasoning. Our understanding of these experiences may develop, but reasoning based on them cannot lead to rejection of them without the entire edifice of knowledge collapsing on itself.
I will have more to say on the rejection of "common sense" in the future. Also, today is my birthday.