Well, it appears that this blog draws to it a significant number of grammar mavens. Who knew? Rather than quibble further about the correct classification of “a priori” and “a posteriori,” let me take a few moments to explain what is actually at stake.
Analytic judgments, Kant says, are judgments in which the predicate unpacks or spells out what is already contained in the subject. Hence, he calls them “explicative.” In the judgment “All bachelors are unmarried,” for example [I like the old-time favorites], the subject term “bachelor” is defined as “unmarried man.” The judgment “All bachelors are unmarried” simply explicates what is contained in the concept of the subject. Synthetic judgments, on the other hand, such as “Most bachelors are unhappy,” add something to the concept of the subject. Hence Kant calls them “ampliative.” [I am expounding Kant here, so don’t pester me with modern revisions of this classical story, please.]
There are some judgments whose truth can be know independently of and hence prior to experience. The judgments can, in other words, be known a priori. “All bachelors are unmarried” is such a judgment, as are all analytic judgments according to Kant. There are other judgments whose truth can be known only on the basis of, or after, experience. These judgments can, in other words, only be known a posteriori. “Most bachelors are unhappy” [supposing this to be true, as I, a married man, confidently believe] is an example.
Can analytic judgments be known a posteriori? Yes. One can imagine a team of not too bright sociologists wanting to know whether all bachelors are unmarried. They get a grant, round up some graduate students, draft a three question survey, and identify a carefully chosen representative sample of the population. They ask each subject three questions: Are you a bachelor? Are you a man? Are you married?” After a careful statistical analysis of the results, they draft a journal article in which they report that, within the margin of error, 100% of bachelors are unmarried. A secondary result is that, within the margin of error, 100% of bachelors are men.
Kant can state with confidence that the proposition “All bachelors are unmarried” is universally and unconditionally, hence necessarily, true. It can be known to be true a priori. But the sociologists are only able to state that the proposition “All bachelors are unmarried” is confirmed with a high degree of probability, within the margin of error. Hence they have only established it a posteriori.
Can a synthetic judgment be known a priori? It would seem not, for, as Kant recognized shortly after delivering the Inaugural Dissertation of 1770, there does not seem to be any way in which we can have knowledge a priori about the independently real.
The Critique of Pure Reason is devoted to this problem.
I trust all of this is clear. The question for Kant is: Can we know a priori the truth of certain propositions [most notably the Causal Maxim] that are synthetic? One can, in abbreviated form, express this as the question “Are there any synthetic a priori propositions?” if one wishes. But to my ear, anyway, that is a misleading way of articulating his central question.