Edge cases, the moral sense and evolutionary debunking

It has been argued that if we are the product of unguided evolution, we would not expect our moral sense to get the moral facts right. I think there is a lot to those arguments, but let's suppose that they fail, so that there really is a good evolutionary story about how we would get a reliable moral sense.

There is, nonetheless, still a serious problem for the common method of cases as used in analytic moral philosophy. Even when a reliable process is properly functioning, its reliability and proper function only yield the expectation of correct results in normal cases. A process can be reliable and properly functioning and still quite unreliable in edge cases. Consider, for instance, the myriad of illusions that our visual system is prone to even when properly functioning. And yet our visual system is reliable.

This wouldn't matter much if ethical inquiry restricted itself to considering normal cases. But often ethical inquiry proceeds by thinking through hypothetical cases. These cases are carefully crafted to separate one relevant feature from others, and this crafting makes the cases abnormal. For instance, when arguing against utilitarianism, one considers such cases as that of the transplant doctor who is able to murder a patient and use her organs to save three others, and we carefully craft the case to rule out the normal utilitarian arguments against this action: nobody can find out about the murder, the doctor's moral sensibilities are not damaged by this, etc. But we know from how visual illusions work that often a reliable cognitive system concludes by heuristics rather than algorithms designed to function robustly in edge cases as well.

Now one traditional guiding principle in ethical inquiry, at least since Aristotle, has been to put a special weight on the opinions of the virtuous. However, while an agent's being virtuous may guarantee that her moral sense is properly functioning--that there is no malfunction--typical cognitive systems will give wrong answers in edge cases even when properly functioning. The heuristics embodied in the visual system that give rise to visual illusions are a part of the system's proper functioning: they enable the system to use fewer resources and respond faster in the more typical cases.

We now see that there is a serious problem for the method of cases in ethics, even if the moral sense is reliable and properly functioning. Even if we have good reason to think that the moral sense evolved to get moral facts right, we should not expect it to get edge case facts right. In fact, we would expect systematic error in edge cases, even among the truly virtuous. At most, we would expect evolution to impose a safety feature which ensures that failure in edge cases isn't too catastrophic (e.g., so that someone who is presented with a very weird case doesn't conclude that the right solution is to burn down her village).

Yet it may not be possible to do ethics successfully without the method of cases, including far-out cases, especially now that medical science is on the verge of making some of these cases no longer be hypothetical.

I think there are two solutions that let one keep the method of cases. The first is to say that we are not the product of unguided evolution, but that we are designed to have consciences that, when properly functioning (as they are in the truly virtuous), are good guides not just in typical cases but in all the vicissitudes of life, including those arising from future technological progress. This might still place limits on the method of cases, but the limits will be more modest. The second is to say that our moral judgments are at least partly grounded in facts about what our moral judgment would say were it properly functioning--this is a kind of natural law approach. (Of course, if one drops the "properly functioning" qualifier, we get relativism.)

A quick heuristic for testing conjunctive accounts

Suppose someone proposes an account of some concept A in conjunctive form:

• x is a case of A if and only if x is a case of A₁ and of A₂ and ... of A_n.

It may seem initially plausible to you that anything that is a case of A is a case of A₁,...,A_n. There is a very quick and simple heuristic for whether you should be convinced. Ask yourself:

• Suppose we can come up with a case where it's merely a coincidence that x is a case of A₁,A₂,...,A_n. Am I confident that x is still a case of A then?

In most cases the answer will be negative, and this gives you good reason to doubt the initial account. And to produce a counterexample, likely all you need to do is to think up some case where it's merely a coincidence that A₁,A₂,...,A_n are satisfied. But even if you can't think of a counterexample, there is a good chance that you will no longer be convinced of the initial account as soon as you ask the coincidence question. In any case, if the answer to the coincidence question is negative, then the initial account is only good if there is no way for the conditions to hold coincidentally. And so now the proponent of the account owes us a reason to think that the conditions cannot hold coincidentally. The onus is on the proponent, because for any conditions the presumption is surely that they can hold coincidentally.

Consider for instance someone who offers a complicated account of knowledge:

• x knows p if and only if (i) x believes p; (ii) p is true; (iii) x is justified in believing p; (iv) some complicated further condition holds.

Without thinking through the details of the complicated further condition, ask the coincidence question. If there were a way for (i)-(iv) to hold merely coincidentally, would I have any confidence that this is a case of knowledge? I suspect that the answer is going to be negative, unless (iv) is something weaselly like "(i)-(iii) hold epistemically non-aberrantly". And once we have a negative answer to the coincidence question, then we conclude that the account of knowledge is only good if there is no way for the conditions to hold coincidentally. So now we can search for a counterexample by looking for cases of coincidental satisfaction, or we can turn the tables on the proponent of the account of knowledge by asking for a reason to think that (i)-(iv) cannot hold coincidentally.

Most proposed accounts crumble under this challenge. Just about the only account I know that doesn't is:

• x commits adultery with y if and only if (i) x or y is married; (ii) x is not married to y; (iii) x and y have sex.

Here I answer the coincidence question in the positive: even if (i)-(iii) are merely coincidentally true (e.g., x believes that he is married to y but due to mistaken identity is married to someone else), it's adultery.