It is not pretended that, at the present stage of its development, economic science is able to provide an organon even remotely approaching to what it imagines for itself as its ideal.

The gravitation constant is the same always. But the economic constants-these elasticities of demand and supply-depending, as they do, upon human consciousness, are liable to vary. The constitution of the atom, as it were, and not merely its position, changes under the influence of environment.