Monday, February 18, 2019

Munchhausen's Trilemma — What Every Atheist Should Know


So you're an atheist and you find yourself in a debate with a theist or an agnostic on some issue relevant to being godless. It could be about morality, or why the universe exists, or how did we all get here, or why our universe happens to be the particular way it is, or a similarly related issue. Perhaps the other person is even another atheist who's just curious and asking questions.

And as witty and as intelligent as you are, for every question of theirs that you answer, they keep asking "Why?" until you've eventually exhausted your explanatory capability, much to your chagrin. This is inevitable, even if you're the world's authority in every field of science and philosophy. At that point, they express doubt that atheism is a coherent position. After all, to them it can't ground the most basic questions about reality in an all-encompassing explanatory framework. Atheism as an explainer just seems to lead to a dead end.

But here's where the clever atheist, who's learned in philosophy comes back. If this were me in such a predicament, I would remind my interlocutor that it is logically impossible to have an all-encompassing explanatory framework. And that's because of a little known trilemma in epistemology known as Munchhausen's trilemma:


Given Munchhausen's trilemma, all explanatory chains must terminate in either an infinite regress, a circular grounding, or an axiom that cannot in principle be further explained. Not even science, math, or logic is immune from the trilemma. They all start with certain fundamental axioms and build up from there.

Let's take morality as an example. Munchhausen's trilemma is necessarily true for all moral systems too. Theists think they have a way out. They don't. Both divine command theory and natural law theory all necessarily terminate in the trilemma. Regarding the former, saying god is identical to the good—which is the most common way divine command theorist try to avoid each horn of Euthyphro's dilemma—strips the definition of "good" of any meaning. It's also circular: god is good and good is god.

It has another problem too: If a devout ISIS member just defined his god—who's perfectly fine with having infidels beheaded just for being infidels—as identical to "good," and a Jesus-loves-everyone-including-abortion-and-gay-marriage liberal Christian defined his god as identical to "good," then I as an atheist have no basis for determining which god is actually identical to the good without an objective basis that exists independent of all gods. Hence no god could be the source of goodness.

Regarding the latter, natural law theory takes our human nature and draws final causes from it. Things that prevent or run contrary to the outcome these final causes are immoral, and things that enhance the outcome of these final causes are moral. But there's nothing necessary about our biological nature, and if it were different our final causes would be different, as well as what's moral and immoral. If god created us with a biological nature where females had to cannibalize the males post coitus, as some species of insects do, then that would be moral. So on natural law theory, what biological nature god created us with was totally arbitrary, since morality depends on a species' nature and there's nothing logically necessary about our nature. Therefore, on natural law theory, the explanatory chain for what's moral ends with god's arbitrary eternal and unchanging will about the nature of the species it would most closely identify with—since nothing logical demands god created human beings with our exact biological properties. God just wanted it that way, and any explanation why will have to be grounded in the trilemma, since a logically necessary explanation is not an option.

The ultimate questions of existence—Why are we here? Why does the universe exist?—will hit the same fate since there is no logically necessary reason why we exist or our particular universe exists. That alone is enough to be able to deduce the necessity of the trilemma. Not even god can escape it.

So when you encounter a person lamenting on the lack of an ultimate explanation in atheism, you can kindly introduce them to the fact that no world view is technically capable of such a feat. All explanatory chains will either go on forever, terminate circularly, or terminate in a brute fact. This may not be psychologically satisfying for most people, especially those raised in a religious context, but there's no avoiding it no matter how hard you try. And once you realize the trilemma and accept its truth, it has the tendency to mitigate your epistemological angst. Personally, I think that out of the three options, a brute fact is preferable. Reality most likely has a fundamental layer that didn't have to be that way, but just is. Asking "Why?" beyond the fundamental brute fact of reality is like asking "Are we there yet?" when you've arrived at your destination: the buck stops here.

We just might not ever know if we've arrived at our destination.

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