During these past few weeks, I have been involved in a heated discussion with one of my philosopher-friends.  The debate revolves around epistemological basis for beliefs and justification – knowledge being defined as justified belief.  I decided to share a part of the argument here, because I would be interested in seeing your take on it.   Philosophy is best learned when we have to argue with a well-prepared, real opponent so if you are interested, by all means, please post your opinion on the matter.

My friend argues that reasoning process itself should be swept clean of all bias and with the use of scientific method (which is unbiased) we arrive at correct conclusions.  If there is another method besides the scientific method which makes arrival at truth possible, he is challenging me to enlighten him as to its structure and details.  And so we have been going back and forth for a few weeks now and plan on doing so until we reach some type of resolution.  I am armored with Aquinas and, honestly, everything else sound I can think of.  Here are three excerpts of his part of the argument – from his comments you will know what my criticisms of his position were  (    :

PART I

My comment was about critical and rational thinking. Widening the debate to issues of free will and physicalism will just cloud the issue. Surely, those issues will be secondary.
We have to distinguish between two different kinds of belief.

First, there’s intuition. Intuitions are automatic beliefs. Intuitions are not rational, although they may eventually become rational. You might call them “pre-rational”. They are not necessarily false, but they are yet to be rationally justified.

Second, there’s rational belief. Rational beliefs are based on explicit deductive and inductive inferences. They are based on reasons that have been checked against facts, and checked against bias in order to exclude false rationalizations.

Critical thinking is the process of taking our beliefs and making them rational.

Here’s the important point: critical thinking isn’t just a matter of pondering and reflecting and eventually accepting or rejecting a belief. People who hold irrational beliefs do so with lots and lots of reflection and rationalization. Rational thinking doesn’t mean “thinking hard” or anything so imprecise.

Rational thinking means

(1) Deductive inference. Given some premises, some conclusions must be true or else you will have a contradiction. For example, if all men are mortal, and Socrates is a man, then Socrates cannot be a man and be immortal without contradicting the premise.

(2) Inductive inference. The past is a guide to the future, even in thought. You cannot be rational without assuming that there are regularities in nature and thought. If you find yourself shipwrecked on an alien world, and the alien sun has risen every day for the last 10 days, then it’s likely that the alien sun will rise again tomorrow. Certainly, it’s more likely than not, and probably close to a 90% chance.

Inductive inference from experience assumes regularities, and that means it assumes there are rules and predictions! Without predictions, there’s no inductive inference, and hardly any rational thinking at all.

The only beliefs one cannot challenge are the rules of rational thinking themselves. Everything else can be criticized to see whether the belief is a proper inference or just an intuition.

Critical thinking means asking ourselves hard questions about our beliefs:

(i) What inferences support my belief? What are my reasons?

(ii) If my belief were false, what differences would I expect to see in the world? Are there more possible worlds in which my belief is true than there are possible worlds in which it is false?

(iii) Am I sampling my thoughts and experiences in a way that is controlled and free of bias? Am I remembering the hits and not the misses? Am I remembering only events with personal significance? Am I rigging the books to get the conclusion I prefer? Overcoming bias generally requires some sort of blind testing.

(iv) Even-handedness. If I hold up reason X for believing Y, are there any other beliefs that must stand or fall as a consequence of X?

Is there anything in the above that you disagree with?

PART II

It’s always a red flag whenever someone says theory X cannot be tested scientifically. What they are saying is that their theory is indistinguishable from their personal bias. If it’s art, that’s fine, but let’s not confuse art with knowledge. If I claim X is true, and I’m making an “is” claim, I had better have scientific proof (or logical necessity) to back it up.

PART III

None of the principles of reason that I outlined make any prior assumptions about naturalism, physicalism or compatibilism.
Tell me which principle of rationality I need to sacrifice, and why that principle makes an assumption of naturalism.