582 SCIENCE PROGRESS 



Mechanism, Life, and Personality. By J. S. Haldane, M.D., F.R.S. 

 [Pp. vi + 139.] (John Murray. Price 2.?. 6d.) 



This small volume consists of four lectures delivered to senior students of the 

 London University, and is an attempt to bring the great biological movement 

 of the nineteenth century into definite relation with the main stream of human 

 thought. 



Dr. Haldane has proved himself well fitted for the task, for he, unlike many 

 men of science, never loses himself in " the snare of words " as Locke called it, 

 and has dealt with a somewhat abstruse subject in an admirably simple and 

 lucid manner. The arguments are so clear, that even those wholly unversed in 

 philosophy will have no difficulty in following it to its striking conclusion. 



The aim of the first two lectures is to examine the hypothesis that living 

 organisms may be regarded as conscious or unconscious physical and chemical 

 mechanisms, and can be satisfactorily investigated from that standpoint. 



The author first states the case of those who hold that the two great physical 

 laws of the conservation of matter and the conservation of energy can be 

 extended with apparently rigorous accuracy to all living mechanisms. We now 

 know, as the fruit of years of experiment and observation, that nowhere does 

 simple protoplasm exist, not even among the lowest and most primitive saprophytic 

 bacteria. 



The Mechanistic Theory is obliged to assume that a living organism, such as 

 man, is a complex system of physico-chemical mechanisms, each of which is 

 controlled by the rest in such a way that the normal structure and activity of the 

 organism is, under ordinary conditions, maintained. Many of these mechanisms 

 have been proved to exist by exact experiment, and hence no real difficulty 

 presents itself in the assumption. The fundamental mistake of the mechanistic 

 physiologists of the middle of the last century was that they completely failed to 

 realise that living structure was organised, and such processes as secretion, 

 absorption, growth, were treated as if each were an isolated physical or chemical 

 process instead of being one side of a many-sided metabolic activity, of which the 

 different sides are indissolubly associated. 



Dr. Haldane, by some admirably destructive criticism, disposes of the 

 mechanistic theory, and leaves us fully convinced of the inadequacy of that 

 theory to explain the phenomena of Life. 



Scientific materialism superseded the scepticism of the Victorian era, and now 

 we are told on many sides that the trend of modern philosophic thought is in the 

 direction of some form of vitalism. It is no longer widely held that "a generation 

 which speculates upon the unknowable sacrifices progress for safety." Dr. Haldane, 

 in his fourth and concluding lecture, comes down definitely on the side of a 

 fundamental dualism. It is, he writes, necessary to draw a sharp and clear 

 distinction between biology which deals simply with organic life, and psychology 

 which deals with conscious life or Personality. He holds that the physiologist, 

 who treats of perception and volition, is going outside his own subject endeavour- 

 ing to explain psychological phenomena in terms which cannot be applied to 

 them. We are thus led on gradually until we find ourselves compelled to adopt 

 the spiritual hypothesis, an attitude of mind with which Henri Bergson, 

 Poincard, and others of the modern French philosophic school have made us 

 familiar. 



Dr. Haldane concludes with an admirably clear summary of his views on the 

 whole subject : 



