From Rudolf Steiner's last published communication:
In the age of natural science, since about the middle of the nineteenth century, the civilized activities of mankind are gradually sliding downward, not only into the lowest regions of nature, but even beneath nature. Technical science and industry become sub-nature.
This makes it urgent for man to find in conscious experience a knowledge of the spirit, wherein he will rise as high above nature as in his sub-natural technical activities he sinks beneath her. He will thus create within him the inner strength not to go under.