§ 4. In addition to these quotations we find in the writings of Aristotle a comparatively full statement of the opinions of the pre-Sokratic philosophers. Aristotle was interested in the work of his predecessors, since he rightly regarded his own system as the crowning result of partial views that had been set forth before. All that is valuable in their work he would give its place in his own philosophy, and their false or partial opinions he would controvert. Accordingly his ordinary method is to commence the discussion of a theme by stating the opinions of his predecessors and criticising them; and it is natural that the early thinkers who first set forth characteristic views with force and vigour should receive the fullest consideration, for indeed this position is still due to them in the history of philosophy. Inasmuch as Aristotle set the fashion for later philosophic writers in collecting and criticising the opinions of earlier thinkers, it is important to form a clear conception of both the excellence and the defects of his method. On a first examination of his statements of these opinions the student is struck by their fullness and comparative accuracy. Emminger[108] has collected and discussed these data, and arrives at the conclusion in every instance that Aristotle’s statement is based on a use of the best materials at his command, and that it reproduces correctly the view of the philosopher in question. It is true that Emminger takes the position of an apologist. There is no doubt, however, that Aristotle was very familiar with the poems of Empedokles, the arguments of Zeno, the system of the Pythagoreans; when he cannot verify his opinions, as in the case of Thales, they are commonly introduced with a λέγεται of caution; and where the views of earlier thinkers seem to be distorted, it is generally due to one of several simple causes which we can estimate with considerable accuracy. My own conclusion is that the data given by Aristotle are of the greatest value for the study of his predecessors, though they are to be used with caution.