Wednesday, March 25, 2009

5.2.1 The Infinite Regress Problem

In The Logic of Scientific Discovery, Karl Popper explored what is called the “Problem of Induction”. This phrase describes the question of whether inductive inferences can be justified, and under what circumstances they are. The problem has two facets: (1) you can’t logically deduce that the inductive process is valid, and (2) using inductive logic to prove itself is “begging the question” (circular reasoning). Even though inference and induction seems to work brilliantly, this paradox continues to haunt us.

One of the larger questions we are trying to answer is, on what assumptions are science and rational empiricism based? If those assumptions could be enumerated, it would then be reasonable to ask why we believe those assumptions - how they can be justified. Given some more thought and analysis, it might be possible to provide good justifications for those assumptions by presenting more fundamental justifications. But then they come under the same kind scrutiny – why would we believe them, ad infinitum? This “infinite regress” is intellectually unsatisfying, because the series of nested justifications never ends. Or, it could mean that the at a deep level level, some unprovable postulates just have to be accepted - that rationality is based on just as flimsy a framework of unproven assumptions as any other faith-based belief system. Or it could end up in a circular argument (e.g., "I like bananas because they taste good"). If any of these are the case, then skeptics of rationality would argue that since its most basic beliefs cannot be justified, we don’t really know anything, absolutely. We are left with only one certainty – that there are no certainties.

Although this does represent a perplexing problem, it has not stymied attempts to overcome it – in fact, there have been many attempts to defeat the infinite regress problem. Some have responded that it is perfectly acceptable to let the justifications roll on to infinity. I have a hard time seeing how that would actually work, though. It is easy enough to just say that regress is not really a problem, but I am hard pressed to imagine a scenario involving more than just a few levels of justification before getting to the very atoms of logic and experience, impossible to go any deeper. The “why / because” back and forth dance can only go so far before it becomes tedious and meaningless.

Another alternative is Foundationalism, which overcomes the infinite regress argument by proposing that some core beliefs are self-evident and obvious, neither requiring justification nor even being capable of justification. A later section of this document goes deeper into this concept. A very similar response is Coherentism, which allows for explanatory circularity involving cross-referencing of justifications. If a diverse, interrelated system of different lines of evidence and belief is consistent, non-contradictory, and mutually supportive of the entire structure, the overall system and the theories that comprise that system gain credibility. In this model, beliefs are like pieces in a puzzle or clues in a murder mystery. They become more believable as they fit with more and more of the interrelated beliefs, facts, evidence, and theories that already are on firm ground. For example, the theory of Evolution gained more credibility and relevance as subsequent discoveries in organic chemistry, molecular biology, geology, paleontology, zoology, botany, anthropology, and archeology showed strong confirmation for it, and even helped advance and deepen the original theory. As a system of beliefs, the theory of Evolution is coherent with the rest of science. The same is true of all the other major branches of science.

Science relies on the principle of induction. This principle allows the inductive process to be put into a logical form capable of providing a basis for the legitimacy of scientific endeavors. Hans Reichenbach wrote, its absence would “mean nothing less than to deprive science of the power to decide the truth or falsity of its theories. Without it, clearly, science would no longer have the right to distinguish its theories from the fanciful and arbitrary creations of the poet’s mind.”

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