further difficulty in assuming that his existence could pass unnoticed at a period marked by intense literary and philosophical activity. Readers who wish for fuller information on the subject will find in Zeller’s pages a careful and lucid digest of the whole controversy leading to a moderately conservative conclusion. Others will doubtless be content to accept Prof. Jowett’s verdict, that ‘on the whole not a sixteenth part of the writings which pass under the name of Plato, if we exclude the works rejected by the ancients themselves, can be fairly doubted by those who are willing to allow that a considerable change and growth may have taken place in his philosophy.’[116] To which we may add that the Platonic dialogues, whether the work of one or more hands, and however widely differing among themselves, together represent a single phase of thought, and are appropriately studied as a connected series. We have assumed in our last remark that it is possible to discover some sort of chronological order in the Platonic Dialogues, and to trace a certain progressive modification in the general tenor of their teaching from first to last. But here also the positive evidence is very scanty, and a variety of conflicting theories have been propounded by eminent scholars. Where so much is left to conjecture, the best that can be said for any hypothesis is that it explains the facts according to known laws of thought. It will be for the reader to judge whether our own attempt to trace the gradual evolution of Plato’s system satisfies this condition. In making it we shall take as a basis the arrangement adopted by Prof. Jowett, with some reservations hereafter to be specified.