This is the motion of changing a single being into two. This is the most obvious way in which cause and effect works, as in the descriptions of modern science. But according to Aristotle, this does not yet explain that of which the motion is, and we must "apply ourselves to the question whether there is any other cause per se besides matter".[5] The formal cause is the form or idea which serves as a template towards which things develop - for example following an approach based upon Aristotle we could say that a child develops in a way partly determined by a thing called "human nature".