What is a synthetic a priori judgment in Kant's philosophy?

In Immanuel Kant's philosophy, synthetic a priori judgments are statements that are both independent of experience and capable of adding new information to a concept. Unlike analytic judgments, which merely unpack what is already contained in the subject, or standard a posteriori judgments, which rely on sensory observation, synthetic a priori statements offer necessary and universal truths about the world. Kant argued that our knowledge of mathematics, natural science, and metaphysics depends entirely on this specific type of judgment.

What we know

• An analytic proposition is one where the predicate-concept is already contained within the subject-concept, making it true by definition. [3]
• Synthetic propositions are those where the predicate-concept is not contained within the subject-concept, thereby adding something new to our understanding. [3]
• Before Kant, philosophers generally assumed that all a priori knowledge had to be analytic. [3]
• Kant argued that our knowledge of mathematics, the first principles of natural science, and metaphysics is both a priori and synthetic, and later philosophers like Willard Van Orman Quine questioned whether a clear distinction even exists. [2, 3]

Still open

• Subsequent philosophers, beginning with Willard Van Orman Quine, have questioned whether a clear and defensible distinction truly exists between analytic and synthetic propositions.

Where to go next

• compared withWhat did Willard Van Orman Quine argue against the analytic-synthetic divide?
• how it workedHow does Immanuel Kant define transcendental idealism?
• a case in pointWhat are the twelve Kantian categories of the understanding?
• what caused itHow did David Hume's skepticism influence Immanuel Kant?
• the bigger pictureWhat is the scope and purpose of the Critique of Pure Reason?
• an unexpected connectionHow does a revolution in astronomy mirror Kant's theory of knowledge?Kant compared his epistemological method of making objects conform to the mind's structures to the way Copernicus shifted astronomy by making viewers orbit the sun.

Sources

• [1]analytic–synthetic distinction (Wikidata Q485413) · CC0 1.0
• [2]Analytic–synthetic distinction · CC BY-SA 4.0
• [3]Critique of Pure Reason · CC BY-SA 4.0
• [4]Immanuel Kant · CC BY-SA 4.0
• [5]Category (Kant) · CC BY-SA 4.0