Authors:

Sir, what is poetry? Why, Sir, it is much easier to say what it is not. We all know what light is; but it is not easy to tell what it is.

In James Boswell 'The Life of Samuel Johnson' (1791) vol. 3, p. 38 (12 April 1776)
Sir, what is poetry? Why, Sir, it is much easier to say what it is not. We all know what light is; but it is not easy to tell what it is.