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How did Kant explain space and time as forms of intuition?

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Marble bust of Aristotle with a beard and draped robe, showing detailed facial features and wavy hair, set against a dark background. — metaphysics Detail of a Roman copy (2nd century bce) of a Greek alabaster portrait bust of Aristotle (c. 325 bce); in the collection of the Museo Nazionale Romano, Rome.

In his transcendental idealism, Immanuel Kant explained that space and time are not properties of things-in-themselves, but rather a priori forms of human sensibility.12

In the Transcendental Aesthetic section of the Critique of Pure Reason, Kant argued that these forms are "intuitions" contributed by the mind itself. They serve as the necessary framework through which all sensory data must pass to be perceived. Because the mind imposes these forms upon experience, human beings can only know the world as it appears to them—as phenomena—rather than as it exists independently of the mind (the noumena or things-in-themselves).321

By positioning space and time as conditions of the subject rather than features of an external reality, Kant sought to explain how synthetic a priori knowledge, such as that found in mathematics and physics, is possible. This "Copernican revolution" in philosophy established that objects must conform to the requirements of human sensibility and rationality to be known.132