In his doctrine of the relation of thought and action Guyau followed the _philosophie des idées-forces_. On the other hand there are very remarkable affinities between the thought of Guyau and that of Bergson. Guyau is not so severely intellectual as Fouillée; his manner of thought and excellence of style are not unlike Bergson. More noticeably he has a conception of life not far removed from the _élan vital_. His “expansion of life” has, like Bergson’s _évolution créatrice_, no goal other than that of its own activity. After Guyau’s death in 1888 it was found that he had been exercised in mind about the problem of Time, for he left the manuscript of a book entitled _La Genèse de l’Idée de Temps_.[50] He therein set forth a belief in a psychological, heterogeneous time other than mathematical time, which is really spatial in character. In this psychological time the spirit lives. The year following Guyau’s death, but before his posthumous work appeared, Bergson published his thesis _Les Données immédiates de la Conscience_ (1889), which is better described by its English title _Time and Free Will_, and in which this problem which had been present to Guyau’s mind is taken up and treated in an original and striking manner. In Guyau, too, is seen the rise of the conception of activity so marked in the work of Bergson and of Blondel. “It is _action_ and the power of life,” he insists, “which alone can solve, if not entirely at least partially, those problems to which abstract thought gives rise.”[51] [50] This work was edited and published by Fouillée two years after Guyau’s death, and reviewed by Bergson in the _Revue philosophique_ in 1891. [51] _Esquisse d’une Morale sans Obligation ni Sanction_, p. 250. Bergson, born in 1859, Professor at the Collège de France from 1901 to 1921, now retired, has had a popularity to which none of the other thinkers of this group, or indeed of our period, has attained. He is the only one of the new idealists or spiritualists who is well known outside his own country. For this reason foreigners are apt to regard him as a thinker unrelated to any special current of thought, an innovator. Although much is original and novel in his philosophy, his thought marks the stage in the development to which the spiritualist current has attained in contemporary thought. The movement of which he forms a part we can trace back as far as Maine de Biran, to whom Bergson owes much, as he does also to Ravaisson, Lachelier, Boutroux and Guyau. Two important books by Bergson came prior to 1900, his _Time and Free Will_ (1889) and his _Matter and Memory_ (1896). His famous _Creative Evolution_ appeared in 1907. It is but his first work “writ large,” for we have in _Time and Free Will_ the essentials of his philosophy.