EXISTENCE ET DÉVELOPPEMENT DE LA VOLONTÉ. I. Existence de la Volonté. By _A. Fouillée_. SUR QUELQUES IDÉES DU BARON D’HOLBACH. By _A. Lalande_. ESSAI SUR LA PHILOSOPHIE DE PROUDHON. By _G. Sorel_. TRAVAUX DU LABORATOIRE DE PSYCHOLOGIE PHYSIOLOGIQUE. CONTENTS: July, 1892. No. 199. L’INCONNAISSABLE DANS LA PHILOSOPHIE MODERNE. By _G. Fonsegrive_. LA MUSIQUE D’APRÈS HERBERT SPENCER. By _J. Combarieu_. ESSAI SUR LA PHILOSOPHIE DE PROUDHON (concluded). By _G. Sorel_. CONTENTS: August, 1892. No. 200. ÉTUDE CRITIQUE SUR LE MYSTICISME MODERNE. By _Rosenbach_. LE DÉVELOPPEMENT DE LA VOLONTÉ. By _A. Fouillée_. LA BEAUTÉ ORGANIQUE: ÉTUDE D’ANALYSE ESTHÉTIQUE. By _A. Naville_. ANALYSES ET COMPTES RENDUS. According to M. Fouillée, the principle which tends to dominate psychology and physiology is the ubiquity of will and of feeling, and consequently of consciousness. Psychology will end by recognising the continuity and the transformation of modes of psychical energy, as physics recognises the continuity and the transformation of modes of physical energy, and philosophy will see in physical energy the external expression of will. M. Fonsegrive maintains that the rejection of metaphysics as science, which marks the modern theory of the unknowable, is the consequence of Kant’s _a priori_ theory as to the origin of our knowledge. The laws of the mind have no real existence prior to experience, and universal and necessary notions can be discovered only by mental analysis. In this manner the existence, and even the essence, of metaphysical beings may be known, but only of such as experience puts in communication with ourselves. Thus we know God as the necessary first cause, although our notion of God is one of negation, of experimental notions. After showing that Spencer’s theory of music had numerous antecedents, and that its conclusions are unacceptable on various grounds, M. Combarieu affirms that the secret of the musical art is the identity of the musical idea with the imitation or expression of the real world. All music contains a double verity; it is the meeting place of the senses and of the rational world confounded in a unity which is the work of art, as man is the combination of a soul and a body confounded in the real unity of life. Spencer is an excessive simplifier, and does not see the complexity of certain questions, which he seeks to resolve by undervaluing them. But he has thrown light on one of the aspects of the musical problem.