  A substantial part of this early dissertation is devoted to a critical discussion of Kant's moral philosophy, and it is striking that although in his general approach and conclusions Moore endorses the kind of idealism advanced by Bradley, he is already critical of Kant's conception of practical reason. He argues that Kant's use of this conception blurs the distinction between ‘the psychological faculty of making judgments and inferences’ and that which is ‘true and objective’. This distinction, Moore maintains, ‘cannot be either done away or bridged over’. Hence, he argues, Kant's conception of morality as founded on a priori principles of practical reason is untenable. It is easy to see how this line of thought could be extended to a general criticism of Kant's conception of the a priori; and it is precisely this generalisation that Moore undertakes in his successful 1898 dissertation. At the same time he comes to see that his previous enthusiasm for Bradley's idealism was not well founded (though it still takes him a little time to accept that the arguments of Bradley and McTaggart against the reality of time are flawed). So it is in this 1898 dissertation that Moore turns decisively against idealist philosophy, both in its Kantian and Bradleian forms.