1.1 Immanuel Kant and my mother
I recall an old Dilnot cartoon in which Dilnot as a child is taken to task by his mother for some naughty behavior. Her rebuke takes the form of the rhetorical question:
Suppose everybody behaved like that?
My own mother was fond of the same question. Like Dilnot in the cartoon, I would then silently rehearse the reasons that her logic was faulty. It is true that it would be bad if everybody were to behave asocially, but I am not everybody; I am just me. If my naughty behavior isn't going to affect anyone else, why does it matter to me what would happen if it did?
Benedict de Spinoza (1985) held the same view as my mother, as he reveals in the following passage on the irrationality of treachery:
What if a man could save himself from the present danger of death by treachery? If reason should recommend that it would recommend it to all men.
Nor is he the only philosopher with a fearsome reputation for analytic rigor to take this line. Immanuel Kant (1993) elevates the argument into a principle of practical reasoning in his famous categorical imperative:
Act only on the maxim that you would at the same time will to be a universal law.
Can such great minds really be wrong for the same reason that my mother was wrong?
It has become traditional to explain why the answer is yes using a simple game called the Prisoner's Dilemma. The analysis of this game is trivial and entirely unworthy of the attention that has been devoted to it in what has become an enormous literature. This chapter begins by defending the standard analysis, and continues by explaining why various attempts to refute it are fallacious. However, the more interesting question is: Why all the fuss? How come some scholars feel such a deep need to deny the obvious?
I think the answer is to be found in the fact that there are circumstances in which an appeal to what everybody is doing is indeed a very good reason for doing the same thing yourself (Section 9).