PRESIDENTIAL ADDRESS 
BIOLOGICAL LAWS AND SOCIAL PROGRESS. 
BY 
H. L. BRUNER. 
In such a meeting as this it is entirely proper to recall the services of 
science to man, the discoveries which have contributed to his health and 
comfort and given him knowledge of the world in which he lives. By the 
aid of science man has acquired such control over nature as his imagination 
formerly attributed only to the gods. Today, he mounts into the air with 
Mercury, dives into the deep with Neptune, and when he speaks from the 
summit of some Mt. Marconi, his voice is heard in the uttermost part of 
the earth. These discoveries, and especially the great services of the sci- 
entist in the world war, have won for science a high place in popular esteem. 
But peace has brought demands that are no less insistent than those of 
war. At the present time all progressive nations are facing certain social 
problems which were already pressing for solution in 1914. In the strain 
and stress of war the issues have been more sharply defined. Scientists may 
assist in the solution of these problems by the contribution of discoveries 
and inventions which make for better living, but such relief will be only 
temporary. A more lasting contribution, I believe, may be made by empha- 
sizing those biological principles which must control all progressive evolu- 
tion. both in society and elsewhere in the organic world. I wish, therefore, 
-in the performance of the task assigned to me as president of the Academy, 
to call your attention to an old theme: namely, the importance of the gen- 
eral laws of biology in social progress. 
That the evolution of human society follows the same laws that control 
evolution in other fields, is a fact often repeated since Herbert Spencer and 
Huxley insisted on its importance. In both cases evolution is essentially a 
process of differentiation and integration of parts or units originally alike 
and equal. The nature of these changes is shown in the embryonic deyelop- 
ment of every higher plant or animal. the multiplication of cells being fol- 
lowed, on the one hand, by division of labor, formation of tissues, organs 
and organ systems, on the other hand, by coordination and integration of 
associated parts to form a complete whole. Societies are formed in the 
same way. Beginning with a group of individuals which do all kinds of 
work, by division of labor and cooperation they form complex organizations 
which are able to accomplish vastly more than separate individuals could 
do. Here, also, as in animal and plant bodies, the greater the division of 
labor, the more dependent become the parts on the whole, the more de- 
pendent the whole upon the parts. : 
This tendency to differentiation in organisms is limited by other laws 
which produce more or less uniformity and stability. Im embryonic life this 
conservatism leads to a repetition of ancestral history, in which the em- 
bryo follows a certain definite path and gives rise to an individual of a 
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