Mysteries which we have driven outside of the boundaries of our knowledge and which we have located and encompassed, such mysteries will not harm us; on the contrary they will stimulate and inspire us in many ways; the dangerous mysteries are those which are hopelessly mingled with our knowledge, and of which we are perhaps unaware.

The History of Science and the New Humanism, Chapter I (p. 60), H. Holt & Co. 1931