A New Evolutionary Debunking Argument Against Moral Realism

Quite a mouthful

Moral realism is the claim that when someone says something like unnecessarily torturing babies is wrong they are expressing a proposition that can be correct or incorrect regardless of peoples’ mental states (preferences, desires, beliefs, etc).

A popular counterargument to this claim is what’s called the evolutionary debunking argument against moral realism. This argument, most famously popularized by Sharon Street and Richard Joyce, goes something like this (the particular framing was taken from Kane B in this video):

Evolutionary Debunking Argument Against Moral Realism:

Premise 1 (Causal Premise): Our evolutionary history explains why we have the moral beliefs that we have.

Premise 2 (Epistemic Premise): Evolution [which selects for survival] is not truth-tracking with respect to moral truth.

Conclusion: Our moral beliefs are unjustified.

Note: This doesn’t have to be evolutionary history. The argument still works if it shows that morals were developed because of societal, cultural, or other explanations as long as they don’t invoke the existence of moral facts.

While this argument seems valid, it doesn’t actually give us reason to reject the existence of moral facts. Rather, it merely gives us reason to think that we don’t have epistemic access to the facts, as evolutionary forces would not have pressured for them. In other words, whatever evolutionary benefit for which morals were developed is true independent of the moral facts. Here, I will make a different but related argument to shows that evolution gives us reason to think that the moral facts don’t exist at all.

For this new argument, we’re going to need to go back to the most fundamental argument for moral realism: the argument from deeply held moral intuitions. The argument goes something like this:

Intuitional Argument For Moral Realism:
Premise 1: Torturing babies for fun (or any other thing that goes against deeply held moral intuitions) seems objectively wrong.

Premise 2: If something seems objectively wrong to that degree, we should think that it is objectively wrong.

Premise 3: Torturing babies for fun could be objectively wrong if and only if moral facts existed.

Conclusion: Therefore, moral facts exist.

As does the initial evolutionary debunking argument, this new argument starts out by giving an explanation for our intuitions that doesn’t depend on moral facts existing — namely, evolution.

New Evolutionary Debunking Argument Argument Against Moral Realism:

Premise 1: Our reasons for thinking that moral facts exist rely on our intuitions about moral facts.

Premise 2: Our intuitions about morals can be explained using other means (evolution, culture, etc) instead of invoking the existence of moral facts.

Premise 3 (Occam’s Razor, or some equivalent heuristic): Given more and less complicated hypotheses that do an equally good job of explaining all of the phenomena (i.e. one that invokes evolutionary reasons and the existence of moral facts and one that just invokes evolutionary reasons), one should only accept the simpler hypothesis.

Premise 4: The simpler hypothesis is the evolutionary explanation without invoking the existence of moral facts.

Conclusion: Therefore, we should not posit the superfluous existence of moral facts.

Explained differently, the new evolutionary debunking argument against moral realism (from now on, NEDAM for short) says that our reasons for thinking that morals exist in the first place (deeply held intuitions) are misguided, and we should reject the most fundamental argument for moral realism: The Intuitional Argument.

The argument becomes even more powerful when combined with J L Mackie’s Queerness Argument against moral realism. Briefly, the Argument From Queerness is the claim that invoking the existence of moral facts requires us to posit the existence of entities that are “utterly different from anything else in the world.” The NEDAM is then strengthened because it states that, on top of postulating the existence of unnecessary facts, moral realists postulate the existence of really really weird unnecessary facts.

While the NEDAM is still subject to the same counters as the initial evolutionary debunking argument, it’s somewhat stronger, so I thought it was worth sharing. Perhaps I will, at some point, write a post about why I think many of the arguments against evolutionary debunking arguments are misguided.

As always, tell me why I’m wrong!