In this book Professor Bergson first deals with the intensity of conscious states. He shows that quantitative differences are applicable only to magnitudes, that is, in the last resort, to space, and that intensity in itself is purely qualitative. Passing then from the consideration of separate conscious states to their multiplicity, he finds that there are two forms of multiplicity: quantitative or discrete multiplicity involves the intuition of space, but the multiplicity of conscious states is wholly qualitative. This unfolding multiplicity constitutes duration, which is a succession without distinction, an interpenetration of elements so heterogeneous that former states can never recur. The idea of a homogeneous and measurable time is shown to be an artificial concept, formed by the intrusion of the idea of space into the realm of pure duration. Indeed, the whole of Professor Bergson's philosophy centers on his conception of real concrete duration and the specific feeling of duration which our consciousness has when it does away with convention and habit and gets back to it natural attitude. At the root of most errors in philosophy he finds a confusion between this concrete duration and the abstract time which mathematics, physics, and even language and common sense, substitute for it.
Applying these results to the problem of free will, he shows that the difficulties arise from taking up one's stand after the act has been performed, and applying the conceptual method to it. From the point of view of the living, developing self these difficulties are shown to be illusory, and freedom, though not definable in abstract or conceptual terms, is declared to be one of the clearest facts established by observation.
It is no doubt misleading to attempt to sum up a system of philosophy in a sentence, but perhaps some part of the spirit of Professor Bergson's philosophy may be gathered from the motto which, with his permission, I have prefixed to this translation: "If a man were to inquire of Nature the reason of her creative activity, and if she were willing to give ear and answer, she would say Ask me not, but understand in silence, even as I am silent and am not won't to speak."
