A judgment is synthetic when it contains more than an elucidation of what is already thought through one of its concepts. Instead, the predicate amplifies what is thought in the subject. For example, in the judgment All bodies have weight, the concept body is amplified by exhibiting the concept having weight, which is not already thought when thinking of body. (This characterization of synthetic judgments opens Kant to the charge of “psychologism.”)
If I say: All bodies are heavy—then the predicate is something quite different from what I think in the mere concept of a body as such. (A7/B11)Since the predicate of a synthetic judgment is not already thought through its subject, something else (X) must be responsible for the unity of the subject and predicate. Ordinarily, the X will be experience, but in some cases it will be something independent of experience.
There is no positive criterion of truth for synthetic judgments, though they are still subject to the principle of contradiction as a negative criterion. (A contradictory synthetic judgment must be false.)
Synthetic judgments may be a priori; or empirical. Kant believed that the notion of a synthetic judgment which is validated independently of experience was an original insight which explains the possibility of mathematics and of a modest metaphysics.
Synthetic judgments are contrasted with analytic judgments, which are explicative, rather than ampliative. In the analytic judgment, a predicate which is contained in the subject is joined to the subject.
[ Lexicon Index | Philosophy 175 Home Page | Lecture Notes Menu ]