The same applies to the concept of inheritance. Through inheritance Goethe saw single, accessory characteristics of a species being carried over from one generation to the next; but never could the reappearance of the basic features of the species itself be explained in this way. He was sufficiently initiated into nature's methods to know that she was not in need of a continuity of the stream of physical substance, in the sense of the theory of inheritance, to guarantee a continuance of the features of the species through successive generations, but that it was her craft to achieve such continuance by means of physical discontinuity.