PHILOSOPHY AND THE STUDY OF PHILOSOPHERS. 9 can be escaped by no one except through the careful study of the growth of metaphysical concepts. We must trace the antecedents of our own ideas in the thought of the past in order to guard against the fallacies due to false philosophical systems. But to see the falsehood of a system clearly we must seek to understand it fully ; and we can only do so by studying it in the light of the social and intellectual environ- ment in which it arose. When we do that, however, we begin to recognise in it a certain relative truth and value. A doctrine which is false, if accepted blindly and upon autho- rity in our age, and w r hich is easily refuted if judged by our canons of scientific criticism, is seen to have been in many respects sound and valid when taken in relation to the time and circumstances of its origin. We may not be prepared to accept the scholastic philosophy of St. Thomas Aquinas as the final word for us ; but we may recognise its great worth as an expression of the central ideas of the thirteenth century by a man of much shrewdness, common-sense and modera- tion. We cannot be Cartesians or Leibnizians now-a-days, and yet we may acknowledge the great debt of modern thought to Descartes and Leibniz more easily than was possible in last century, when Cartesianism and Wolfianism had become new scholastic systems in those universities where mediaeval Aristotelianisin had been supplanted. But, if we have reached this appreciative manner of regarding the great systems of a sufficiently remote past, we have surely got beyond the stage of looking on them simply as errors and the parents of errors against which we have to be on our guard. When the religious or the philosophical systems of the past are studied in what we have come to consider
- ' the historical spirit," when criticism passes from merely
refuting opinions to showing how and why these opinions came to be held, above all when the conception of develop- ment or evolution is extended from the natural world to the world of human thought, we have left behind the purely negative attitude to ideas that we no longer accept, and we come to see the long series of attempts to grapple with the central problems of knowledge and reality not as stray opinions with which we do not happen to agree, but as parts of one continuous movement in which our own thinking is itself included. The development of ideas is, indeed, in some respects more intricate and difficult to trace than de- velopment in the organic sphere. The genealogy of ideas (as of institutions) is more complex than that of animal or vegetable species. Still the leading threads can generally be detected; and just because we are dealing with expressly
