One of the things that used to bother me about Ockham’s Razor was the almost coincidental way it “just so happens” that the simplest solution is most likely to be correct. Oh really? How convenient for us simple-minded investigators! Are you sure there isn’t some kind of scam going on here?
As it turns out, there isn’t. In a world where “true” and “false” are consistently meaningful terms, the law of parsimony will always apply. The correct explanation will be the simplest explanation that accounts for all the facts.
To understand why this is so, we just need to consider what “truth” is. Truth is defined by its consistency with reality, and reality is consistent with itself. Conversely, falsehoods are not consistent with reality, by definition, and not infrequently fail to be consistent even with themselves.
When we try to explain something—as opposed to superstitiously attributing it to magical causes—our goal is to discover the truth, which means we want an explanation that’s consistent with reality. Any time we fail, we produce an explanation that contains inconsistencies with reality and possibly with itself as well. These inconsistencies will also require explanation, which in turn will make our original, incorrect explanation more complicated. The simplest explanation will be the one that has the fewest such complications, and the correct explanation will be the one that has zero additional inconsistencies to explain. Thus, the simplest explanation is the most likely to be correct because the nature of error makes erroneous explanations inherently more complex.
As Mark Twain put it, it’s easier to tell the truth because there’s less to remember. True explanations have the advantage of reflecting the inherent self-consistency of reality itself, and not uncommonly have the characteristic of being consistent with real-world evidence that you don’t even know yet. Thus, for example, Darwin’s theory of evolution turns out to be consistent with discoveries that Darwin himself knew nothing about, like DNA and radiometric dating methods, whereas creationist speculations keep raising new inconsistencies with each new “explanation” for why we don’t see stars being created six to ten thousand light years away, or how so many modern, surviving species can be descended from small numbers of “kinds” aboard the ark if there’s no such thing as descent with variation from common ancestral species.
This fact, plus an understanding of how superstition and rationalization work, give us an opportunity to test what we think we know, and examine our beliefs for evidence that we might, perhaps, be clinging to false ideas. But that’s going to be tomorrow’s post.