Page:Popular Science Monthly Volume 14.djvu/343

Rh the social body. They ought to coöperate for the welfare of the whole,

2. Evolution.—All the laws of evolution which have been discovered in organisms apply also to society, but with certain limitations, which I believe are very significant.

(a.) Law of Differentiation.—The most fundamental law of evolution is differentiation. The organism, as I have described it above, with its cells of diverse forms and functions, was not thus constituted in the beginning of its existence, but gradually became so by a process of differentiation. In the early stages of an organism the constituent cells are all alike in form, and each performs, though imperfectly, all the functions necessary in this early stage. But, as the organism develops, the cells begin to take on different forms, and to perform different functions, and this process of differentiation continues until, in the mature condition of the highest organisms, each group of cells (or each organ) is limited to the performance of one function only. This one function is its only evidence of life. Now, concurrently with this increasing differentiation of form and limitation of function, there is, of necessity, an increasing mutual dependence of parts, and a sacrifice of the independent life of the part to the common life of the whole. In the lowest condition of the organism, where the cells are all alike, and each performs, though imperfectly, all the functions, there is a very considerable, sometimes a complete, independent life in each cell; so that it may be separated without injury either to itself or to the community of cells: the independent life is large, the common life is feeble. But, as we rise in the scale of organization, the independent life of the part is merged more and more into the general life of the whole—is sacrificed, and goes to make up the common life—until, in the mature condition of the highest organisms, the independent life of the constituents is reduced to a minimum, while the common life is advanced to a maximum. This complete merging of the independent life of the part into the common life—this identification of life with function—is the ideal of the animal organism: the nearer it approaches this condition the higher manifestly is the organism.

Or take instead that larger organism, more nearly resembling, and therefore better illustrating, the social organism, viz., the whole organic kingdom,—its present diverse condition has been reached also only by a process of differentiation. Commencing in the earliest times, with similar and independent beings, by a continual process of separation and differentiation, animal forms have become more and more diverse, occupying different places and performing different functions in the economy of Nature; the higher becoming still higher, and the lower becoming lower; the mutual dependence and interaction of all parts becoming greater and greater, until the ideal seems almost reached in the present fauna and flora. If we can conceive any organism still higher than man, or lower than the monera—if we can conceive a