Agreement with experiment is the sole criteria of truth for a physical theory. - Pierre Duhem

Now, a symbol is not, properly speaking, either true or false; it is, rather, something more or less well selected to stand for the reality it represents, and pictures that reality in a more or less precise, or a more or less detailed manner.

A physical theory reputed to be satisfactory by the sectarians of one metaphysical school will be rejected by the partisans of another school.

« La Logique peut être patiente, car elle est éternelle. »
("Logic can be patient because it is eternal.")
ibid. p. 150