Kant's epistemology is a clear and explicit response to Hume's scepticism, an attempt to provide both a foundation for empirical scientific knowledge and to show the limits of such knowledge. The failure of the Cartesian epistemological project prior to Kant's work is the failure to show how the conformity between subjective perceptions and objects existing independent can be demonstrated. Specifically, the conformity of knowledge to objects remained highly problematic for both Descartes and Hume. Kant's transcendentalism is premised on dualism between the self and the not-self and between the phenomenal and the noumenal. It is a method through which Kant hopes to circumvent the problem of how to verify the evidence of the senses by correlating this evidence with external objects which cause the sensory events which make up experience. In the Critique of Pure Reason Kant seeks to establish the ground for what he calls a "rational doctrine of the soul".