Lamarck was the first to present the theory of Evolution in a thoroughly scientific manner. Then Darwin discovered “the great principle which rules the evolution of organisms”; the principle of “natural selection.” Then Weismann repudiated current ideas as to how the fittest “arrived,” or “originated,” and presented in their place a theory of his own, which is still under discussion. DeVries raised the question as to whether new species “arrive” by a gradual accumulation of tiny changes, or by sudden leaps--mutations--and demonstrated the latter by his experiments with the evening primrose. And now comes Kropotkin with the question, “Who are the fittest?” What constitutes the fitness, which makes for survival? Are those organisms the fittest which are constantly waging a war of extermination against every other organism in the struggle for existence, or, are those the fittest which co-operate with each other in the preservation of the common life of all? The raising of this question brings to light another striking instance of the influence of class interests on scientific thought. It is a matter of common observation that any class, struggling for what it conceives to be its own emancipation, looks to the past for justification and precedent. In the English speaking world there is a widely prevailing opinion that the Magna Charta, extorted from King John at Runnymede, is the foundation of modern liberty. The French bourgeoisie, struggling to overthrow the feudal monarchy, sought its justification in that “state of nature” which a despotic monarchy was said to contravene. Thus writers like Rousseau idealized nature, representing it as comparatively perfect, and declared that a restoration of “natural rights” was essential to liberty. But when this same bourgeoisie had won its victory and enthroned itself, and instead of increasing the liberty, had in many respects, deepened the degradation of the mass of the French people, its ideas about the “state of nature” underwent a radical change. And this happened not only in France but wherever the bourgeoisie triumphed. Now the “state of nature” was one of constant carnage; nature was “red in tooth and claw.” And this chamber of horrors was supposed to support the exploitation of labor, and countenance a brutalization of childhood that constitutes the blackest stain on human history. So strong was the swirl that Huxley was swept into it; but, although he maintained the “gladiatorial” view of nature, he repudiated the social atrocities which capitalist apologists such as Spencer sought to deduce from it. In later years, Spencer partially abandoned his premise as to the animal world but, strangely enough, kept it intact for primitive man.