However, the logical forms serve as what we already have before we could embark on discovering the categories, for they are abstracted from publicly available discourse. Thus the logical forms are the ratio cognoscendi of the categories. My own italic. Transcendental philosophy is not to be classified with either the trivially analytic propositions that come from the analysis of given concepts, nor with the synthetic a priori knowledge that transcendental analysis itself explains. . . . This, however, is not possible in the case of the relational categories.
Most concept can serve either as the subject or the predicate of a judgment.