There is only one law of Nature-the second law of thermodynamics-which recognises a distinction between past and future more profound than the difference of plus and minus. It stands aloof from all the rest.... It opens up a new province of knowledge, namely, the study of organisation; and it is in connection with organisation that a direction of time-flow and a distinction between doing and undoing appears for the first time.

The Nature of the Physical World: Gifford Lectures (1927) (ed. Cambridge University Press, 2012) - ISBN: 9781107663855