Page:Mind (New Series) Volume 9.djvu/493

 THE PRINCIPLE OK I.KAST CTION, ETC. 479 (1) A principle of least exertion possible ; (2) A principle of lessening exertion ; (3) A principle of the most effective exertion, i.e., of least exertion for a given result or for a given exertion, a maximum of result. For brevity's sake we shall refer to these respectively as the principles of Inertia, Facilitation and Economy. III. THE PRINCIPLE OF INERTIA. The most unambiguous expression of this principle psychological principle that I have come across is found in an article contributed, in 1894, by M. Guillaume Ferrero to the February number of the Revue Philosophique. It is entitled ' Mental Inertia and the Law of Least Effort '. In a footnote on the first page we read : 'The merit of having introduced the idea of Inertia into Psychology belongs con" fessedly to M. Lombroso who made use of the idea in order to explain the innate conservatism of the human mind. In the present article I am proposing a fresh application of this same idea which appears to me to be a very fruitful one.' As regards Mental Inertia, M. Ferrero takes up an extreme position. He maintains that when the brain is not stimulated by sensations, it exists in a state of absolute inertia. The law of mental inertia is for him merely the statement of the fact that man receives from without the impulse to feel, or think, or strive. It is the tabula rasa in another form. The impulsion towards psychical activity once received, man's main tendency, in accordance with the principle of Least Effort, is to make the least mental effort possible. Man, naturally, has a supreme horror of work in any form, and the law of Least Effort expresses this tendency of a man to employ such processes, muscular or mental, as require the least exertion. M. Ferrero then appeals to the facts of Evolutional Sociology as proving in a most marvellous manner that this law of Least Effort controls the psychical activities of man. Man's tendency throughout, he argues, has been, when confronted by the necessity of change, to aim at such provisional adaptations as involved the least outlay of effort, even at the cost of obtaining only the most insignificant and fleeting results. Such a clearly defined attitude as that of M. Ferrero lends itself easily to criticism. Let us first take M. Ferrero's conception of mental inertia as a fundamental psychological