"Did this state of mind remain always so, every one would, without scruple, give it the name of perfect madness; and whilst it does last, at whatever intervals it returns, such a rotation of thoughts about the same object no more carries us forwards towards the attainment of knowledge, than getting upon a mill-horse whilst he jogs on in his circular track would carry a man a journey."
— Locke, John (1632-1704)
See John Locke, Posthumous Works of John Locke (London: Printed by W.B. for A. and J. Churchill, 1706). <Link to ESTC><Link to Google Books>
Text from Some Thoughts Concerning Education and Of the Conduct of the Understanding, eds. Ruth W. Grant and Nathan Tarcov (Indianapolis: Hackett Publishing Company, 1996).