Supererogation on Aristotelianism

The cheetah whose maximum speed is 40 mph is subnormal. The cheetah whose maximum speed is 58 mph is merely normal. The cheetah whose maximum speed is 80 mph is supernormal. An Aristotelian can accommodate these three judgments by saying that the form of the cheetah sets two things for the cheetah’s speed: a norm and a comparison. The norm specifies what is needed for being a healthy cheetah, and the comparison specifies what is a better speed than what. And the comparison can hold among instances that meet the norm, in which case the better instance is supernormal, and it can hold among instances that fail to meet the norm, too.

Having both a norm and a comparison for a type of good is especially important in the case of open-ended goods with a lower limit but no upper limit. Thus, no matter how much a human knows, knowing more would be better (in respect of knowledge). But there is such a thing as knowing enough to be a flourishing human knower. But we can also have a norm and a comparison in the case of things where there is an upper limit. Thus, a heart that is too small or too big is unhealthy. But is a range of healthy heart sizes (specified by the norm), and some of those sizes are healthier than others (specified by the comparison). Somewhere in that range there could even be (though vagueness and multidimensionality of comparison make that unlikely) a single optimal heart size.

What is true for dispositions (maximum speed) and physical arrangements is also true for operations. There is a normal cheetah running operation, a subnormal and a supernormal one. (Note that in some cases the supernormal one will be slower than the merely normal one, since sometimes energy needs to be conserved.)

The central Aristotelian insight I want to have in ethics is that just as there is proper function in the operation of the legs, there is proper function in the operation of the will. If so, then we would expect there to be a norm and a comparison: some instances of the will’s operation are normal and some are subnormal. And among the normal ones some will be better than others. Thus, in a case where multiple operations of the will are possible, that operation that is normal but better than another normal operation is supererogatory, while an operation that is normal but not better than another normal operation is merely permissible.

There is metaphysically nothing special about the supererogatory or the obligatory on the Aristotelian picture. They are just the instances of a general phenomena in the special case of the operation of the will.