1 64 HOLISM AND EVOLUTION chap. 



influence of life or mind over the body. Leibniz, however, 

 pointed out in answer to Descartes that force (as energy 

 was then called) is not only quantitative but also directional 

 in character. And the second law of motion according to 

 Newton made this perfectly clear. The direction in which 

 a force is acting can be altered only by another force, and 

 this change of direction would therefore involve an expendi- 

 ture of force or energy. If, therefore, the mind has a 

 directive influence over the body, it can exercise this only 

 by way of adding to or subtracting from the energy of the 

 body considered as a closed system, and would therefore be 

 in conflict with the first law of Thermodynamics. Now 

 in the body as a closed system experiment or observation 

 has never yet shown any such addition or subtraction of 

 energy. The energy put into a living body by way of food, 

 heat or otherwise is always, within the limits of error, 

 equalled by the energy of the work done, the heat pro- 

 duced, and the waste products thrown off. As an energy 

 system the living body is unaffected by life or mind or any 

 other factor of a non-physical character. There can, there- 

 fore, be no such direction of the energy of a living organism 

 by life or mind as is assumed; and if there were, the effect 

 would at once be detected in an alteration of the amount 

 of energy in the body. The first law of Thermodynamics, 

 therefore, seems to negative this assumed power of direction 

 of life or mind over the body, and seems to be fatal to any 

 view of directive interaction between the two. Either the 

 first law must be given up, or life and mind are nullities: 

 such are the fatal horns of the dilemma on which we are 

 impaled. But the surrender of the first law is not to be 

 thought of. Although not exactly proved in a rigorous 

 mathematical sense, it is a norm of science which works 

 successfully in practice and which has never been known 

 to be contradicted by any actual observations. It may be 

 that in view of the recent discoveries of the New Physics, 

 which associates the concepts of energy and mass very 

 closely, the law may have to be expanded so as to 

 include both the energy and mass of any closed system. 



