I find these metaethical debates really interesting (and important, though I know others disagree![1]), and Iâve tried to follow the debates and arguments long after I actually studied philosophy. Iâm not an academic philosopher though, so I wonât try to summarise the philosophical history of the literature or give a comprehensive reading list. Instead, Iâll try to give an interested laymanâs outline
* * *
Iâll summarise[2] the general Evolutionary Debunking Argument (EDA) as the following:
If evolution is true, then moral intuitions do not reliably track moral facts
If moral intuitions do not reliably track moral facts, then we are not justified in believing any particular moral facts
Evolution is true
And therefore, by a chain of logic, we conclude that:
C. We are not justified in believing any particular moral facts
The biggest disagreements here are, from my understanding, about premise 1. You could potentially also disagree with premise 2, though to me it seems most disagreements about it would more likely be disagreements about premise 1. I would be very surprised to see any respected moral philosopher try to attack premise 3! Thatâs potentially why they donât get into the details of evolutionary psychology that you know so well, because it doesnât seem to affect the structure of the argument.
One common response is to say that you could deploy this argument against all human intuitive faculties, such as intuitions about our sense data, our social intuitions, even intuitions about mathematics, and so on. We can believe that these were generated by an evolutionary process, but nevertheless reliably track the truth of their content, so why should we think any differently about our moral intuitions?
Another response is to point out that, logically, this argument doesnât prove that moral facts do not exist. This is true, but I find this incredibly unconvincing! If thereâs no causal way for a fact about the world to reach the human brain, saying âbut it still could be trueâ seems like incredibly weak sauce to me, but as Iâm not an academic philosopher I may not be doing that justice here.
The intuitionist defence (at least as far as I understand Huemerâs intuitionism) is to say that our intuitive beliefs about moral facts are simply more strongly supported than any scepticism or debunking argument about moral facts and so we should reject the latter. This is akin to the Moorean switcheroo but applied to metaethics rather than external world scepticism.[3]
The moral sceptic, I think, shouldnât be too convinced by these. Our moral intuitions are meant to track moral facts, but it doesnât seem that once we accept an evolutionary story for them that we have any reason to believe that there are such a thing as moral facts at all, rather than our moral intuitions about them. This is related to Harmanâs argument that Mogensen mentions in the podcast, and I must admit that this seems intuitively (ha) very strong to me. Though in the end, Iâm not sure it really matters.[4]
Nevertheless, the strength of Evolutionary Debunking Arguments (EDA) is also not just one that strikes at Effective Altruism but at all moral frameworks, including our critics and people who donât care about philosophy but just want to get on with their lives.
Usually this kind of argument is paired with a non-naturalist moral realism that seems popular in academic philosophy, but I also find unconvincing, mainly due to Mackieâs argument from queerness having a stronger intuitive pull for me than the non-naturalism of moral facts.
If anyone can source this R. M. Hare quote for me then Iâll offer to donate ÂŁ50 toward a charity of your choiceâeveryone seems to cite âNothing Mattersâ in his book âApplications of Moral Philosophyâ, but as far as I can tell it doesnât seem to be there. I find this upsetting, since itâs a pretty close statement of my metaethical beliefs, but I canât seem to prove its accuracy.
JWSâthanks for this comment; it helps me get a little closer to understanding the anti-EDA position.
You mentioned âyou could deploy this argument against all human intuitive facultiesâ. Well, maybe. But I would draw a pretty strong distinction between evolutionary epistemology (including reasons why our perceptions and cognitions are under selection to be roughly accurate in some biologically relevant ways) versus evolutionary ethics (which canât really run the same kind of veridicality argument for why our moral intuitions should be accurate reflections of some external moral truth).
Long story short, if an animal has the cognition âthis cliff is steep and I would die if I fell off itâ, there are pretty good reasons why evolution would nudge such cognitions to be accurate. But if an animal has the moral intuition âmy mate deserves punishment if she has sex with another maleâ, there are pretty good reasons why evolution would favor that intuition, without that intuition carrying any truth-value beyond âthis intuition tends to promote paternity certainty and protects reproductive successâ.
I find these metaethical debates really interesting (and important, though I know others disagree![1]), and Iâve tried to follow the debates and arguments long after I actually studied philosophy. Iâm not an academic philosopher though, so I wonât try to summarise the philosophical history of the literature or give a comprehensive reading list. Instead, Iâll try to give an interested laymanâs outline
* * *
Iâll summarise[2] the general Evolutionary Debunking Argument (EDA) as the following:
And therefore, by a chain of logic, we conclude that:
The biggest disagreements here are, from my understanding, about premise 1. You could potentially also disagree with premise 2, though to me it seems most disagreements about it would more likely be disagreements about premise 1. I would be very surprised to see any respected moral philosopher try to attack premise 3! Thatâs potentially why they donât get into the details of evolutionary psychology that you know so well, because it doesnât seem to affect the structure of the argument.
One common response is to say that you could deploy this argument against all human intuitive faculties, such as intuitions about our sense data, our social intuitions, even intuitions about mathematics, and so on. We can believe that these were generated by an evolutionary process, but nevertheless reliably track the truth of their content, so why should we think any differently about our moral intuitions?
Another response is to point out that, logically, this argument doesnât prove that moral facts do not exist. This is true, but I find this incredibly unconvincing! If thereâs no causal way for a fact about the world to reach the human brain, saying âbut it still could be trueâ seems like incredibly weak sauce to me, but as Iâm not an academic philosopher I may not be doing that justice here.
The intuitionist defence (at least as far as I understand Huemerâs intuitionism) is to say that our intuitive beliefs about moral facts are simply more strongly supported than any scepticism or debunking argument about moral facts and so we should reject the latter. This is akin to the Moorean switcheroo but applied to metaethics rather than external world scepticism.[3]
The moral sceptic, I think, shouldnât be too convinced by these. Our moral intuitions are meant to track moral facts, but it doesnât seem that once we accept an evolutionary story for them that we have any reason to believe that there are such a thing as moral facts at all, rather than our moral intuitions about them. This is related to Harmanâs argument that Mogensen mentions in the podcast, and I must admit that this seems intuitively (ha) very strong to me. Though in the end, Iâm not sure it really matters.[4]
Nevertheless, the strength of Evolutionary Debunking Arguments (EDA) is also not just one that strikes at Effective Altruism but at all moral frameworks, including our critics and people who donât care about philosophy but just want to get on with their lives.
This is just meant to be a summary, not publishable philosophy!
Usually this kind of argument is paired with a non-naturalist moral realism that seems popular in academic philosophy, but I also find unconvincing, mainly due to Mackieâs argument from queerness having a stronger intuitive pull for me than the non-naturalism of moral facts.
If anyone can source this R. M. Hare quote for me then Iâll offer to donate ÂŁ50 toward a charity of your choiceâeveryone seems to cite âNothing Mattersâ in his book âApplications of Moral Philosophyâ, but as far as I can tell it doesnât seem to be there. I find this upsetting, since itâs a pretty close statement of my metaethical beliefs, but I canât seem to prove its accuracy.
JWSâthanks for this comment; it helps me get a little closer to understanding the anti-EDA position.
You mentioned âyou could deploy this argument against all human intuitive facultiesâ. Well, maybe. But I would draw a pretty strong distinction between evolutionary epistemology (including reasons why our perceptions and cognitions are under selection to be roughly accurate in some biologically relevant ways) versus evolutionary ethics (which canât really run the same kind of veridicality argument for why our moral intuitions should be accurate reflections of some external moral truth).
Long story short, if an animal has the cognition âthis cliff is steep and I would die if I fell off itâ, there are pretty good reasons why evolution would nudge such cognitions to be accurate. But if an animal has the moral intuition âmy mate deserves punishment if she has sex with another maleâ, there are pretty good reasons why evolution would favor that intuition, without that intuition carrying any truth-value beyond âthis intuition tends to promote paternity certainty and protects reproductive successâ.