given of all the factors individually considered. So is it, too, with the physicist. Say the problem is the propagation of sound through air, and the interpretation of its velocity—say that the velocity as calculated by Newton is found less by one-sixth than observation gives, and that Laplace sets himself to explain the anomaly. He recognizes the evolution of heat by the compression which each soundwave produces in the air; finds the extra velocity consequent on this; adds this to the velocity previously calculated; finds the result answer to the observed fact; and then, having analyzed the phenomenon into its components and measured them, considers his task concluded. So throughout: the habit is that of identifying, parting, and estimating factors, and stopping after having done this completely.
This habit, carried into the interpretation of things at large, affects it somewhat as the mathematical habit affects it. It tends toward the formation of unduly-simple and unduly-definite conceptions; and it encourages the natural propensity to stop short with proximate results. The daily practice of dealing with single factors of phenomena, and with factors complicated by but few others, and with factors ideally separated from their combinations, inevitably gives to the thoughts about surrounding things an analytic rather than a synthetic character. It promotes the contemplation of simple causes apart from the entangled plexus of cooperating causes which all the higher natural phenomena show us, and begets a tendency to suppose that, when the results of such simple causes have been exactly determined, nothing remains to be sought.
Physical science, then, though indispensable as a means of developing the consciousness of causation in its simple definite forms, and thus preparing the mind for dealing with complex causation, is not sufficient of itself to make complex causation truly comprehensible. In illustration of its inadequacy, I might name a distinguished mathematician and physicist whose achievements place him in the first rank, but who, nevertheless, when entering on questions of concrete science, where the data are no longer few and exact, has repeatedly shown defective judgment. Choosing premisses which, to say the least, were gratuitous and in some cases improbable, he has proceeded by exact methods to draw definite conclusions, and has then enunciated those conclusions as though they had a certainty proportionate to the exactness of his methods.
The kind of discipline which affords the needful corrective is the discipline which the Concrete Sciences give. Study of the forms of phenomena, as in Logic and Mathematics, is needful, but by no means sufficient. Study of the factors of phenomena, as in Mechanics, Physics, Chemistry, is also essential, but not enough by itself, or enough even joined with study of the forms. Study of the products themselves, in their totalities, is no less necessary. Exclusive attention to forms and factors will not only fail to give right conceptions of prod-
