The conclusion seems to be irresistible that such laws of nature as the principle of conservation of energy, the principle of conservation of momentum and the law of gravitation are necessary consequences of our modes of measurement. They are, in fact, elaborately disguised identities which could have been predicted a priori by a being of sufficiently powerful analytical insight who fully understood all that is implied in the way we measure space-time intervals.

As quoted by Gerald James Whitrow, The Structure of the Universe: An Introduction to Cosmology (1949)