The paper aims to explain and illustrate why Einstein and Kant, relativity and transcendental idealism, came to be discussed in one breath after the Special theory of relativity had emerged in 1905. There are essentially three points of contact between the theory of relativity and Kant's objective idealism. The Special theory makes contact with Kantian views of time; the Generaltheory requires a non-Kantian view of geometry; but both relativity theories endorse a quasi-Kantian view of the nature of scientific knowledge. The paper shows that Einstein is a Kantian in his insistence on the synthesis of rationalism and empiricism, but not in the details of his physics.