So far in these essays I have done my best to avoid any explicit discussion of logical theory. Whenever I have seen any danger of a collision with formal logicians, I have sheered away, and put aside the contentious concept—‘logical necessity’, or whatever it might be—with a note to reconsider it later. By now the list of items to be reconsidered has become pretty long; and we have seen plenty of signs of a divergence between the categories of practical argument-criticism and those of formal logic. The time has come when the collision can no longer be avoided: rather, our task will be to ensure that we meet it head-on, and with our grappling-irons at the ready.

In the first part of this essay, I shall proceed in the manner of a scientist. I shall begin by stating my hypothesis: namely, that the categories of formal logic were built up from a study of the analytic syllogism, that this is an unrepresentative and misleadingly simple sort of argument, and that many of the paradoxical commonplaces of formal logic and epistemology spring from the misapplication of these categories to arguments of other sorts. I shall then explore the consequences which follow from treating analytic syllogisms as a paradigm, and especially the paradoxes generated by treating as identical a number of ways of dividing up arguments which are genuinely equivalent in the case of analytic syllogisms alone.