In the course of Part III we have made a general survey of the thought of some of the greatest names in philosophy, with special reference to their attitude to metaphysics. We observed, as time went on, a gradual widening of interests. First, the question to which philosophers addressed themselves was that concerning the reliability of our impressions or ideas. Then, after Hume’s destructive analysis, an attempt was made by Kant to settle once and for all the status of metaphysical enquiry—an attempt about which the fairest thing we can say is that it failed magnificently. Finally, Hegel, taking a synoptic view of philosophy, originated a system which, in spite of the obscurities of its exposition, straddles modern thought like a colossus: so that whatever attitude we may finally choose to adopt towards it, we cannot deny that it raises a number of profound problems, and that it provides a formidable challenge to those who dismiss metaphysics as mere obscurantist mumbo-jumbo. In this final section we shall be concerned with the state of philosophical enquiry at the present time. As this is a task requiring great condensation, we shall inevitably be obliged to omit reference to many names of deserved importance. But all the while we shall be bearing in mind the main currents of European thought, and the general attitude, whether friendly or otherwise, assumed towards metaphysics. And there is one school of thinkers to which we shall be paying particular attention, because its adherents have waged unceasing war upon meta-physics234 for almost a century : this is the school of Positivism. Positivism, which is the form taken by the anti-philosophia perennis at the present day, represents perhaps the most resolute attack upon metaphysics that has ever been launched.