What is Life?

by Erwin Schrödinger

For developing better methods, innovations, even if as yet unproved, must be tried out. But in order to ascertain whether the innovations improve or decrease the output, it is essential

that they should be introduced one at a time, while all the other parts of the mechanism are kept constant.

The evidence that two features, similar in appearance, are based on the same principle, is always precarious as long as the principle itself is unknown.