I am back from my vacation in Liberty City 🙂

Seriously though, gta 4 is a lot of fun and very addictive!

I have recently been very interested in showing that rationalism is hopeless. To be open, I confess that I used to be a rationalist when I was younger. When I first started studying philosophy I was very influenced by Descartes and found his talk of clear and distinct ideas and ‘the light of nature’ very compelling. There is no suprise here, as rationalism has been the dominant view in the Western tradition since its inception. But, as rationalists like Bonjour admit, rationalism has suffered several notorious and embarrassing setbacks. Perhaps the first of which goes back to Gallileo showing empirically that Aristotle’s physics was wrong in assuming that heaverier bodies fall faster than lighter bodies. More dramtically, perhaps, is the discovery of non-Euclidean geometry which showed that various of the fundamental postulates of geometry were not necessary (like the parralel postulate). We should perhaps add to this the discovery of Russell’s paradox and the various self-referential semantic/syntactic problems (i.e. Godel, the liar, etc) which have led to the development of alternative logics.

What this shows is that intellectual seemings are fallible. It cannot therefore be argued that something seeming to need no empirical support and seeming to be justified purely by reason is enough to establish that the fact in question is really justified independently of experience or not. So, take 1+1=2. It certainly seems that this is true, in fact it is hard for me to imagine how it could be otherwise. There is a strong subjective sense of certainty that I experience when I think about it. All of this is no doubt true. But we have as of yet no reason to think that it is REALLY necessary, or that its justification is independant of experience. This is because we can not tell a priori whether the intelectual seeming is indeed correct. This shows that rationalism is in serious trouble. There is no other reason to take rationalism seriously other than the strong pull these rational insights have on us.

One might want to reply by saying that is overly skeptical. We shouldn’t abandon a priori knowledge just because we have mistakenly identified somethings as necessary which weren’t. So too, the objector goes on, just because we hallucinate doesn’t mean that we don’t normally see objects. Fair enough. But then what we need is an actual account to back this up. What is the difference between the cases? We can give that in the empirical case. We can describe ways in which we could find out whether the person was hallucinating or not based on our ability to monitor the brain of the animal in question and our visual impressions of the experimental set up. We can give a sketch, if not every detail, of a story which desribes how the brain interacts with the enviornment it finds itself in and generates representations of that environment. But can you do the same for rationalism? To date no one has. What is an eternal, necessary, non-physical/non-natural object like a number or modus ponens really like? How do we interact with it? No one knows. How could they?

Now this would be a pressing concern if it were impossible for us to fully understand the world we live in except for the truth of rationalism. But this certainly isn’t the case. We have good candidates for materialistic accounts of every disputed area. For instance, in the area I know most about, we have the mind-brain identity theory and the higher-order theory of consciousness. I do not mean to say that we know that they are true, but only that they are viable candidates. For all we know right know they could be true. They have not been absolutely refuted by any a priori arguments, nor have they shown themselves to be inconsistent with the findings of science, quite the converse actually. As for math and logic we have either constructivism or Mill’s view that they are empirical generalizations (I interpret this to mean that they are an attempt to model the way that the physical world works and to grow into Quine’s indispensibility argument that the justification for mathematic is empirical), or a more modern version of deflationism or fictionalism about this stuff. The same is true for ethics.

Again, none of these has been demonstrated to be correct. The point, rather, is that we should prefer natuaristic/materialistic accounts ove their non-natural/non-physical competitors. They automatically become more plausible because of their reliance on the more plausible empiricist/scientific account of knowing.

Tanasije has recently offered up Einstein as an example of how empirical science is dependent on a priori knowledge. His point seems to be that once Einstein had his two fundamental principles (i.e. the principle of relativity and the principle of the constancy of the speed of light) he was able to use ‘pure reason’ and deduce a priori the rest of his physics. But the question of a priori knowledge, I think, is the question of the status of the first principles and the status of the rules that we use to deduce the rest of the physics. It is only if you think that the two principles + rules for deduction are known to be necessary facts about the nature of reality independently of experience and solely by reason.

The empiricist can account for what Einstein did; the two principles followed from empirically validated theories of the time (the principle of relativity is stated by Galileo and is a part of Newtonian physics as Einstein knew it and the constancy of light is predicted by Maxwell’s equations). The rules that are used to deduce (i.e. classical logic) are highly useful empirical generalizations. So Einstein does indeed start from first principles and deduce physics (if that is indeed what happened), but nothing in the story told by the empiricist is really independent of experience.

In order to have some serious rationalism going on, one would have to add to Tanasije’s accoount the claim that Einstein’s principles and the rules of classical logic are known by reason to be necessary facts about reality. Einstein does seem to cite a thought experiment as evidence for the constancy of the speed of light. He says he imagines chasing after a beam of light. What would it look like? If Einstein could catch up with the beam and look at it how would see the light standing still, which is unintuitively odd. So, he must not actually be able to catch up to the beam. But the only way that that is possible is if its speed were constant relative to Einstein no matter how fast he went. QED.

But is this really evidence for rationalism? Not quite. Some scientists (Paul Davies, for instance) think that that the speed of light may have been slowing down since the Big Bang. What is going on here seems to be this. We have a theory wich is the one that best unites disperate phenomena and is empirically adequate. We usually have outlying data and often scientists take creative leaps to integrate these outlying data points and thereby unite more disperate phenomena and provide greater empirical adequacy. It is plausible to think that Einstein himself was motivated by a conflict between theories he found intuitively compelling for the reasons cited above.

The moral of the story? Intuitions are theory driven and not ‘tother way ’round!