Under the impulse of the technical requirements of capitalism, the evolution of natural sciences became a triumphal march of the human mind. Nature was subjugated first through the discovery of its laws by the human mind, and then by the material subordination of the known forces of nature to the human will in the service of our main object, the production of the necessaries of life with a minimum expenditure of energy. But this bright shining light rendered, by contrast, the gloom which surrounded the phenomena of human society only the darker, and capitalism in its development still accentuates this contrast, as it accentuates and thus renders more easily visible and intelligible all contrasts. While the natural sciences dispensed with all mysterious secrecy within their narrower domain, the darkness shrouding the origin of ideas still offered a welcome refuge to the belief in miracles on the spiritual field. Capitalism is now approaching its decline. Socialism is near. And the vital importance of this transition in human history cannot be stated more strongly than in the words of Marx and Engels: "This concludes the primary history of man. He thereby passes definitely out of the animal kingdom." The social regulation of production makes man fully the master of his own fate. No longer does any mysterious social power then thwart his plans or jeopardise his success. Nor does any mysterious natural force control him henceforth. He is no longer the slave, but the master of nature. He has investigated its effects, understands them, and presses them into his service. For the first time in his history he will then be the ruler of the earth. We now see that the many centuries that filled the history of civilization were a necessary preparation for socialism, a slow struggle to escape from nature's slavery, a gradual increase of the productivity of labor, up to the point where the necessaries of life for all may be obtained almost without exertion. This is the prime merit of capitalism and its justification, that after so many centuries of hardly perceptible progress it taught man to conquer nature by a rapid assault. At the same time it set loose the forces of production and finally transformed and bared the springs of the productive process to such a degree that they easily could be perceived and grasped by the human mind; this was the indispensable condition for the control of this process.