No reason justifies disbelief.

[LadyForCamus]

I mean, an axiom is not absolute knowledge. I can't think of any knowledge that I have that could qualify as distinctively innate, and completely divorced from sensory input.  Can you?

Yeah, actually.  Human beings aren't born a blank slate.  I mentioned smiling in another post, not specifically directed at you..but that;s just one example.  There's a great deal of common behavior, and it would be difficult to argue that all of this is accounted for by us somehow all having the same empirical observations, at least not as the empiricists who envisioned both the tabula rasa and empiricism had thought.  We used to think that neurons didn't even form connections until they had some experience to build connections from, and the contents of those neurons, so far as we can tell, amount to all of our knowledge no matter what it's ultimate source may be.  We no longer believe that to be the case..because we've seen that it's not.  

We've always had this bouncing around in the back of our heads (and sometimes the front)..we were aware even when we lacked clarity on what it was we were aware of.  We used to call this sort of thing "instinct", our "our nature" (and hey, we still employ the terms).  Some intuition may be accounted for by it, but all of it qualifies as innate or nativist candidate.  Anything we are born possessing the knowledge required to accomplish is unlikely to be a product of any empirical observation..or at least any empirical observation we can understand the means or timing of, or possess ourselves as the source.  As with intuition above, this is something empiricists have to grapple with.  Even if we were to rehabilitate empiricism in light of this, and far be it from me to claim that we can't, it will still have been the case that empiricism was wrong as conceived.

Okay.  All fair points. But, perhaps "knowledge" is a misnomer when talking about these in utero instincts or reflexes. You're right; I don't "know" how to smile because I spent several weeks walking around watching other people on the street smile, and then practiced in the mirror until I got it right, but that doesn't turn these neurological reflexes into something more than the purely physical effects of a physically developing neurological system, just like it wouldn't be quite right to say that a fetus responding to light in the womb "has knowledge" of how to kick its legs. It's a learned, physical ability.

Even still, the capacity for these reflexes is intertwined with sensory experience, severely limited though it may be in early life. The fetus is responding to sensory input (light) in the example I just mentioned. And, it is suspected that many fetuses dream of the sounds, tastes, and sensations they experience in utero at quite an early gestational age. There is no tabula rasa. Humans are physical beings that begin having some base level of experience as soon as the neurological system is mature enough to start processing its external environment. The learned physical abilities of premature neurological development can hardly be conflated with intuitive, metaphysical knowledge, and I find it hard to believe that that is what most intuitivists mean when they're talking about intuitive knowledge versus empiricism. They still necessarily depend on a physical brain capable of experiencing, on some level, whatever exists outside of it. I suppose I could possibly get on board with this idea you mentioned, nativism, as at least it doesn't seem to be proposing some kind of woo-substance outside of the natural world. Either way, I clearly suck at this. What is your best argument for empiricism as the foundation of knowledge?