Rationality

I interpret Mr. Latar's response as follows:

(1) It is rational to believe in the reliability of induction.

(2) We have no evidence for the reliability of induction.

(3) Conclusion: it is rational to believe without evidence.

However, this fails on the first point. We do have evidence of induction; mountains of it, really. As Mr. Latar points out, the sun has always risen in the past, so we expect it to rise tomorrow.

What David Hume was attempting to point out was not that evidence was lacking, but rather, that proof was lacking. We have no deductive way to show that induction is rigorously and necessarily true. Nonetheless, despite this formal deductive failure, all sane (dare I say rational?) people act as if induction were as true as any formally defined proof.

(Hume's point was that we make certain assumptions about the world, ones that we cannot show to be true with our formal systems. This anticipates Goedel's proof that all formal systems contain truths they cannot prove. I have always understood this to be a limitation of formal systems, rather than a dire comment on the intractability of truth.)

But we cannot write off his argument just yet. Even if the question of evidence is misplaced, we can extend it to proof. Is it rational to believe in things you cannot prove? Clearly it is, since we both agree that induction is rational. Does this mean that science and theology are indistinguishable?

No, and for a parsimonious reason. Theologians also depend on the same assumption. The notion that the world is law-governed is as necessary to thought as are the laws of logic and identity; without these assumptions, we would be unable to form coherent thoughts of any kind.

So both theologians and scientists accept the value of induction, and label it rational, despite its un-provable nature. How now shall we distinguish between them? The answer is, the difference between scientists and theologians is that theologians accept one more assumption: namely, that God exists. And we already understand that the principle of parsimony excludes extraneous assumptions.

If Mr. Latar can show that the concept of God is necessary to understanding the world, then he can show that the assumption is as warranted as the assumption of induction. However, the history of science demonstrates that God is not necessary to understanding.

Even if at least one un-provable assumption is necessary to make sense of the world, this does not mean that un-provable assumptions have a free ticket. The principle of parsimony requires us to restrict ourselves to as few entities as possible; and un-provable assumptions are entities as much as anything else. We have to construct our rational understanding of the world out of as few pieces as possible.

Hence, the decision to include induction as a rational belief despite deductive proof for it does not equally privilege all other un-proven assumptions. Since induction is a common feature of theologians, scientists, and indeed the more mentally active animals, we can just accept it as a fait accompli and go on. But, unless you can show that this minimal tool-set requires you to include the additional component of God, parsimony requires us to reject God, just as we reject all entities that are not either (a) testable, or (b) unavoidable.

It might be rational to believe in a few things you must assume; but it is not rational to believe in more than you must assume.

Micheal Planck

Words: 600 approx