The Fallacy of “What Would Happen if Everybody Did That?”

Abstract

We are all familiar with the homily, What would happen if everybody did that? Sometime ago the underlying this was defended at length by Marcus Singer in his classic book, Generalization in Ethics (abbreviated to GE).1 Although the book has enjoyed a good deal of discussion, most of the criticisms have failed to illuminate in a complete and thorough way the fallacy of this exceedingly complex argument. To this end, I wish to show, first, that What would happen if everybody did that? commits the fallacy of division in a fundamental way, but more importantly, to show that Singer's reply to the counterexamples illustrating the fallacyhis doctrinefails, itself committing the fallacy of composition. The reiterability doctrine, very roughly, is an attempt to indicate how the above contains, as part of its own logical structure, a formal procedure for determining morally relevant act-descriptions. It seems to me that this doctrine is really the most significant aspect of the logic of type arguments, but is as far as I can tell, the most neglected by Singer's critics.2 The result has been not only to render much of the criticism of Singer incomplete and misplaced (as I have indicated), but to allow an important facet of the universalizability thesis to go unchallenged in more recent discussions of the subject (see infra , n. 11). This article's main purpose, then, is to use Singer as a foil for exposing an aspect of the thesis that is intriguing in its own right and one that appears to offer to some writers a compelling line of argument. i. Following Singer, we shall begin by labeling Suppose everyone did that? as the generalization argument (abbreviated to GA). Concisely paraphrased, GA tells us that x, as a kind of act , is wrong if the consequences of everyone's doing x would be undesirable. Singer tries to illuminate its logical structure, as well as its alleged rationality, by deducing it from two more fundamental principles, which he takes to be self-evident: