 One reason Kant may not have noticed the differences between his different characterizations of the analytic was that his conception of “logic” seems to have been confined to Aristotelian syllogistic, and so didn’t include the full resources of modern logic, where, as we’ll see, the differences between the two characterizations become more glaring (see MacFarlane 2002). Indeed, Kant demarcates the category of the analytic chiefly in order to contrast it with what he regards as the more important category of the “synthetic,” which he famously thinks is not confined, as one might initially suppose, merely to the  empirical.[2]  He argues that even so elementary an example in arithmetic as 7+5=12 is synthetic, since the concept of 12 is not contained in the concepts of 7, 5, or +,: appreciating the truth of the proposition would seem to require some kind of active “synthesis” by the mind uniting the different constituent thoughts (1787 [1998], B15). And so we arrive at the category of the “synthetic a priori,” whose very possibility became a major concern of his work. Kant tried to show that the activity of synthesis was the source of the important cases of a priori knowledge, not only in arithmetic, but also in geometry, the foundations of physics, ethics, and philosophy generally, a controversial view that set the stage for much of the philosophical discussions of the subsequent centuries (see Coffa 1991, pt. I).