It was against this kind of confusion, against the transference of the concepts of one science into another, which was the favourite device of positivism, that Croce continually reacted in his criticism of contemporary thought. He instinctively knew the value of distinctions, and also the value of unity; but he would never pay for unity at the expense of the fine, precise, necessary distinctions. This explains why for a certain number of years he may have appeared as a man occupied in the pursuit of two quite different and unconnected lines of research: his literary friends used to look on his economic studies with wonder and distrust, as on a strange whim and a total waste of time, while the economists more or less resented the intrusion of the outsider. But it explains also why, when he finally attempted to give shape to the conclusions he had reached in regard to one particular group of problems, his grasp of the essential unity and his power to build an inclusive and unspecialized conception of reality, were made visible at once. There was no special problem of thought which could be treated apart from an either implicit or explicit view of the whole of reality: there was no solution of any particular problem which would not affect, and in turn be affected by, the solution of every other problem. Or, to say the same thing in different words, philosophy was a system, not in the sense that a rigid logical scheme could once and forever fit the ever moving stream of reality, but because it is impossible to think the distinctions without the unity, or the unity without the distinctions. That which appears to us, psychologically, as the main characteristic of Croce's mind, transforms itself into the intrinsic logic of his system, in which the principles of unity and of distinction are, as we shall see, fundamental.