LIFE AND MECHANISM.

Dominion, Volume 6, Issue 1575, 19 October 1912, Page 4

LIFE AND MECHANISM.

We publish in another column a letter from Professor Laby, in which he takes exception to a statement by Mr. M'Dougall, the Reader in Mental Philosophy at Oxford (quoted in The Dominion on Saturday last) that "no single organic function has yet been found cxplicable in purely mechanical terms; even such relatively simple processes as the secretion of a tear or tho exudation of a drop of sweat continue to elude all attempts at complete explanation in terms of physical and chemical science-'' Professor Labs' expresses the opinion that if this statement of the position was written recently it ignores the striking discoveries in physiology so ably set forth in Professor SchaeFEr's British Association .address. Mr. M'Douoall's assertion, we may explain, is to be found in a little book on Psychology, published during the present year in the Home University series, every volume of which is written 1 by a recognised authority, and the fact that Professor J. Arthur Thomson is one of the editors is a sufficient guarantee that the scientific department of the undertaking will be thoroughly reliable and up-to-date. Docs Professor Laby really contend that some organic functions can be completely explained in terms of physical and chemical science 1 His interesting quotation from Professor Schaefer's address certainly does not warrant any such contention. The dcscrip--1 tion of the part played by the hormones, the secreting glands, and other organs of the body, makes a trulv wonderful story; but no new. epoch-making discovery is revealed in the address—this at any rate is the opinion of such eminent authorities as Sir E. Ray Lankester and Dr. A. R. Wallace. In view of these facta it ia safe to assume that M)i, M'Dougall. who is in the front rank

of English psychologists, was, broadly, speaking, fully awaro when he wrote the book from which the quotation was taken, of the facts so ably marshalled by Puofessok Schaefer. Indeed, he expressly states that the student of psychology must master as fully as possible all that the anatomists and physiologists can tell him of the functions of the organs of the living beings he studies, and it is only fair _to assume that he has done so himself. In any ease Mn. M'Dougall's assertion has the full support of no less an authority than Professor J. A. Thomson, one of the leading exponents of' Darwinism, who declares that "no complete physicochemical description has yet been given of a distinctly vital activity." Of course physics and chemistry play a very important part in helping us to understand organic functions, and the mechanistic hypothesis has led to great discoveries; but as a complete explanation they have been tried and found wanting. Is not Professor Laby confusing description with explanationl Professor Schaefer, in the passage quoted, gives a wonderful description of certain organic functions; but the mere presence of such terms as "may be essential," and "it; is inferred,' is sufficient to show, not only that his explanation is not complete, but also that even his description is not without gaps. _ Nor does Professor Laby's quotation from M. Gley carry us any further, for this authority merely states that the genesis and action of the highest faculties of man are"conditioned"—he does not say "explained"—by the purely chemical action of a product of secretion. Professor Laby himself only claims that a distinct step has been made towards a phy-sico-chemical explanation. The position is put quite clearly and plainly by Professor Thomson in the following paragraph:—

If we inquire into the passage of digested food from the alimentary canal inlo the blood, or the interchange of Safes in the lungs, or the filtering that goes on in the kidney, we certainly find that these involve physico-chemical processes, and wc detect in their occurrence nothing that contradicts the principles of physics and chemistry; and yet the physico-chemical formulae do not suffice for a complete description of the vital function. They do not quite fit; the living cells make a difference —a difference which we haw at present to accept as a fact. In spite of the marvellous extension of scientific knowledge in modern times, it is still true that science lias no complete and final explanations; and if we push our inquiries far enough back we eventually find ourselves in a cloud of fundamental mysteries which_ the human intellect is unable to pierce.