It was a crisis, in fact, for philosophy. Was it to become merely a universal science? Was it to abandon the task of solving the problems of the universe by rapid intuitions and a _priori_ constructions and undertake the construction of a science of the whole, built up from the data and results of the science of the parts—_i.e._, the separate sciences of nature? Was there, then, to be no place for metaphysics in this classification of the sciences to which the current of thought was tending with increasing impetuosity? Was a science of primary or ultimate truths a useless chimera, to be rejected entirely by the human mind in favour of an all-sufficing belief in positive science? These were the questions which perplexed the thoughtful minds of that time. We shall do well, therefore, in our survey of the half century before us, to investigate the two problems which were stressed by Renan in the essay we have quoted, for his acute mind possessed a unique power of sensing the feeling and thought of his time. Our preliminary task will be the examination of the general attitude to knowledge adopted by the various thinkers and schools of thought, following this by an inquiry into the attitude adopted to science itself and its relation to philosophy. I With these considerations in mind, let us examine the three currents of thought in our period beginning with that which is at once a prolongation of positivism and a transformation of it, a current expressed in the work of Vacherot, Taine and Renan. Etienne Vacherot (1809-1897) was partially a disciple of Victor Cousin and a representative also of the positivist attitude to knowledge. His work, however, passed beyond the bounds indicated by these names. He remained a convinced naturalist and believer in positive science, but, unlike Comte, he did not despise metaphysical inquiry, and he sought to find a place for it in thought. Vacherot, who had won a reputation for himself by an historical work on the Alexandrian School, became tne director of the Ecole Normale Supérieure, an important position in the intellectual world. He here advocated the doctrines by which he sought to give a to metaphysics. His most important book, _La Métaphysique et la Science_, in three volumes, appeared in 1858. He suffered imprisonment the following year for His liberal principles under the Empire which had already deprived him of his position at the Sorbonne.