In commenting upon Maimon's contribution to the modern theory of knowledge, Cassirer ascribes to him an admirable tour de force.¹ He believes that Maimon, grasping in all its profundity the problem of the object of experience as posed by Critical Philosophy, managed to think its solution in a way which, in principle, corresponds to Kant's own in the third Critique. But, according to Cassirer, Maimon did not share Kant's critical reservations; in fact, he transcended them towards Leibniz" idealist metaphysics. Within the multitude of Leibniz" metaphysical theories, he succeeded in isolating the essential, methodologically most significant moment, which also comprises the culmination of seventeenth-century rationalism: the causal definition.