John Locke Quote

The study of mathematics would show... the necessity there is in reasoning, to separate all the distinct ideas, and to see the habitudes that all those concerned in the present inquiry have to one another, and to lay by those which relate not to the proposition in hand, and wholly to leave them out of the reckoning.

An Essay Concerning Human Understanding and a Treatise on the, Conduct of the Understanding, A Treatise on the Conduct of the Understanding, Section 7 (p. 494), James Kay, June & Company. 185