A group of us at Cato are reading Derek Parfit’s Reasons and Persons. It’s a difficult read, as I think even Parfit’s fans will admit. I am often struck by how his very formal and rigorous model moral theories have little relation to anything that people act upon, or even argue for, in the real world. Partly I suspect this owes to the Hayekian incompleteness of evolved moral norms. If our norms are always being built up and reworked gradually over time, we shouldn’t expect mathematical precision from them, today or ever.
But Parfit does discuss two types of theory that I encounter all the time.
First, in everyday life we often rely on what Parfit calls “common‐sense morality” — a morality defined by our relationships to particular people, such as “our children, parents, friends, benefactors, pupils, patients, clients, colleagues… or fellow‐citizens” (p 95). Common‐sense morality urges unequal moral weightings in our considerations of these people, and, well, most people find that to be common sense. (By contrast, a purely utilitarian morality might demand that we discount our particular relations to them, and treat all people only with regard to aggregate happiness.)
Second, Parfit describes a type of moral theory that strikes me as very common in political philosophy and even in practical politics. This is Parfit’s Ideal Act Theory. He writes:
One part of a moral theory may cover successful acts, on the assumption of full compliance. Call this part Ideal Act Theory. This says what we should all try to do, simply on the assumptions that we all try, and all succeed (p 97).
Even in the short snip that I’ve given here, it’s obvious that Parfit never intends an Ideal Act Theory to stand alone on any question of morality. Indeed, in his next paragraph he writes:
[I]t is not enough to decide what we should all ideally do. We must take into account these four facts:
(a) We are often uncertain what the effects of our acts will be;
(b) some of us must act wrongly
(c) our acts are not the only effects of our motives;
(d) when we feel remorse, or blame each other, this may affect what we later do, and have other effects. (ibid)
Often, though, and particularly in arguments about politics, arguers seem unable to get past the Ideal Act Theory portion of their reasoning. Attempts to do so are met with some variant on “Well, if everyone did like I told them to, then everything would go well.” Here are some examples:
Radical pacifism is an Ideal Act Theory. A world populated only by radical pacifists would, I trust, be a peaceful world. A world populated by 99% radical pacifists and 1% fascists would be Hell on earth.
Many strains of anti‐immigration politics are Ideal Act Theories. If no one crossed the border without permission, we wouldn’t be having this problem. While this is certainly true, it gives us little or no guidance us in determining which border crossings should be allowed or in how to treat people who cross without permission. I have the sense that these are fundamentally not just uninteresting questions to opponents of immigration, but embarrassing ones.
Advocating abstinence alone as a response to teen pregnancy is an Ideal Act Theory. It’s certainly true that abstinence prevents pregnancy, every single time. But it’s a good deal less clear that teens will always be abstinent, or that we can do very much to make them so. On the margin, advocating abstinence will perhaps move some of them in that direction — an empirical question we need not cover here — but even if it does, it’s still clearly not a complete treatment of the subject.
Just Say No arguments are Ideal Act Theories as applied to drug policy. If no one used drugs, then, rather obviously, there would be no need to worry about any possible bad effects from using drugs. Yet again, though, we get no guidance from the theory as to how we should act in a world of less than full compliance. That world of never‐perfect compliance is precisely the one for which we should be legislating.
Many and possibly all forms of economic collectivism appeal implicitly to the good results that would allegedly come from full compliance, while discounting the fact that full compliance never arrives. Otherwise reasonable questions about how to treat noncompliers are met with demands that we all ought to become more generous or altruistic.
Ideal Act Theories can be found all over the political spectrum, and probably also among libertarians (I’ll leave finding them as an exercise to the reader). What I strongly suspect, however, is that thinkers in the libertarian tradition are much more apt to presume noncompliance than others. Hayek’s work is a good example of this; in particular, noncompliance to established legal rules can drive change in a polycentric legal order. Elinor Ostrom has also done some very interesting work in this area, showing in particular that agents faced with commons problems don’t necessarily behave in the ways that an Ideal Act Theory would predict (pdf):
Fully rational individuals are presumed to know (1) all possible strategies available in a particular situation, (2) which outcomes are linked to each strategy given the likely behavior of others in a situation, and (3) a rank order for each of these outcomes in terms of the individual’s own preferences as measured by utility. The rational strategy for such an individual in every situation is to maximize expected utility. While utility was originally conceived of as a way of combining a diversity of external values on a single internal scale, in practice, it has come to be equated with one externalized unit of measure – such as expected profits. This model of the individual has fruitfully generated useful and empirically validated predictions about the results of exchange transactions related to goods with specific attributes in a competitive market but not in a diversity of social dilemmas.
It is strange, I think, that in everyday life we generally rely on common‐sense morality, with Hayekian (and by no means horrible) results. But in our politics, we so often turn to Ideal Act Theory, and we are mystified when it doesn’t work out very well.