Christo Stoev

A posteriori is that contentful component of any given knowledge that is invariably present in experience and is in the end the component of sensation. I. e. the a posteriori is always given through affection or sensation.

In Latin “a posteriori” means “from what comes after” or “from the latter”. In general, theoretical context this is understood as from experience or through experience. That is why the a posteriori, in contrast to the a priori is what originates from experience, i. e., from perception as a component of experience and in the end from sensation as a component of perception. This is so because “all sensations as such are given only a posteriori. It should be emphasized that the a posteriori component of any experience (which in its capacity of experience, i. e. empirical knowledge will contain in contrast a priori structures too) is sensation and its correlate matter. Accordingly, Kant asserts: “The matter in our knowledge is what makes it to be called a posteriori knowledge”.

With a view to the above, the following fine distinction between the a posteriori and the empirical could be drawn – if the a posteriori is the component of matter of sensation, then the empirical is that which is always mixed with the matter of sensation too (although it contains other components). The a posteriori of sensation is precisely that necessary component of any experience that makes it empirical, i. e. of mixed composition, impure.  

Because of this the a posteriori does not concern the form at all but always only the content or, as already mentioned, the matter of sensation. Thence it should be clear that “the matter of any appearance is given to us only a posteriori. Here the modification “only a posteriori” is important because the matter of appearances, as a correlate of sensation, can never be given a priori, before experience. In contrast, it is “the form that we can know only a priori”.


Kant, Immanuel (1974) Kritik der reinen Vernunft. – In: Werkausgabe in 12 Bänden. Band III/IV. Suhrkamp.

Kant, Immanuel (1998) Critique of Pure Reason, Cambridge: Cambridge University Press.

Allison, H. (2004) Kant’s Transcendental Idealism: An Interpretation and Defense, New Haven and London: Yale University Press, Revised and Enlarged Edition.

Höffe, O. (1994) Immanuel Kant, Albany: State University of New York Press.

How to Cite:

Stoev, Christo (2021) A posteriori, in Thesaurus. Sofia University Dictionary of Philosophy. Online edition. Sofia: St. Kliment Ohridski University Press, 2021, ISSN 2815-2832.