Secondly, it is alleged by some defenders of the real distinction that this latter view of the nature of existing contingent reality is a cardinal doctrine in the whole philosophical system of St. Thomas, and of scholastics generally: so fundamental, in fact, that many important doctrines, unanimously held to be true by all scholastics, cannot be successfully vindicated apart from it.(130) To which it is replied that there are no important truths of scholastic philosophy which cannot be defended quite adequately apart altogether from the view one may hold on the present question; and that, this being the case, it is unwise to endeavour to base admittedly true doctrines, which can be better defended otherwise, upon an opinion which can at best claim only the amount of probability it can derive from the intrinsic merits of the arguments by which it is itself supported.(131) Before passing from this whole question we must note the existence of a third school of thought, identified mainly with the followers of Duns Scotus.(132) These authors contend that the distinction between essence and existence is not a real distinction, nor yet, on the other hand, is it merely a virtual distinction, but one which they call _formalis, actualis ex natura rei_, that between a reality and its intrinsic modes. It is better known as the “Scotistic” distinction. We shall see the nature of it when dealing _ex professo_ with the general doctrine of distinctions. The multiplicity of these views, and the unavoidable difficulty experienced in grasping and setting forth their meaning with any tolerable degree of clearness, would suggest the reflection that in those controversies the medieval scholastics were perhaps endeavouring to think and to express what reality is, apart from thought and “independently of the consideration of the mind”—a task which, conceived in these terms, must appear fruitless; and one which, anyhow, involves in its very nature the closest scrutiny of the epistemological problem of the power of the human mind to get at least a true and valid, if not adequate and comprehensive, insight into the nature of reality. CHAPTER IV. REALITY AS ONE AND MANIFOLD.