Abstract
We study twentieth-century biological sciences as experimental sciences by historically reconstructing the uses of experiments. Concepts like artificial, natural, and inventions, are handled so as to show how much current biological thought has been constructed on the basis of the invention of different kinds of experiments, instruments, and technical devices, experimental systems, and ideas concerning the fonctioning of nature. It is suggested that the frontier that may separate the natural from the artificial has already been crossed. Human intervention in the natural phenomena through reproducible experiments hints to a view of current biological knowledge as a permanent invention of nature.