"Science deals with but a partial aspect of reality, and... there is no faintest reason for supposing that everything science ignores is less real than what it accepts. ...Why is it that science forms a closed system? Why is is that the elements of reality it ignores never come in to disturb it? The reason is that all the terms of physics are defined in terms of one another. The abstractions with which physics begins are all it ever has to do with..."