the edible and the non-edible. Sensation is originally limited to such things as are of practical importance in the struggle for existence; it is the will (in the broadest sense of the term) that impels the sensations to new differentiations. And just as in the case of sensation so it is with knowledge in general. Every thought, every idea describes a more or less conscious and definite tendency of life.
Fouillée regards the application of the analogy of mental life, the most immediate experience which we possess, as furnishing the possibility of a metaphysics. Our knowledge of mental life however does not rest upon psychology alone, but likewise upon sociology; the individual and the social, liberty and solidarity are inseparable. This theory which Fouillée applied to the sphere of sociology and ethics (La science sociale contemporaine, 1880; Critique des systemes de morale contemporaine, 1883) likewise acquires cosmological significance for him. The universe must be conceived as a grand total, a community of striving energies. But in this sphere we cannot attain anything more than a hypothetical scheme, for the synthesis which forms the completion of our knowledge cannot be carried out positively—as in the cases of the finite synthesis of the special departments of phenomena. But this nevertheless furnishes us a criterion by which to judge the various metaphysical systems: such a system is complete in proportion as both multiplicity as well as unity, analysis as well as synthesis, receive due recognition (L'avenir de la Metaphysique, 1889).
