Valid and sound
On Friday, in Josh Schechter’s Advanced Deductive Logic class, Josh made a side remark about the misconception that logic is about how we humans do things rationally. It’s a good point, I think, because while some arguments may be logically sound and valid, human argumentation does not necessarily mirror “pure” logic (”pure” in quotations because I’m not really sure what I mean by that). A comic to explain this:
It’s not made clear often enough how so many beliefs we all have in common depend on a network of trust effect, kind of parallel to Popper’s falsifiability; that is, we don’t necessarily know how to prove to our own satisfaction that the world is round, but we learned it from someone we trusted either to have seen and been convinced by a proof, or who learned (perhaps at some remove) from someone who saw and was convinced by such a proof. Also, when it comes to secondary school stuff like that there’s always the possibility of going and looking it up, which is not so true when it comes to properties of space-time under Einstein’s model, that would require years of education in the relevant maths.
(Hmm, I drew that parallel badly; Popper’s falsifiability requires that for a proposition to be scientific, it must make predictions that can be tested. It is not necessary for an individual reader of a proposition to actually test it, for it to be scientific; but such a proposition is most useful when you can be reasonably sure that someone in the wider community has tested or will test it. If you get me. :-)