And it is notable that he gives this answer when writing of the concept which interests us here, and which I shall call the epistemological concept of simplicity; for he continues: 'Even if we are unable to explain what is really meant by 'simplicity' here, we must yet recognize the fact that any scientist who has succeeded in representing a series of observations by means of a very simple formula (e.g. by a linear, quadratic, or exponential function) is immediately convinced that he has discovered a law.'