"But neither can this be said; for though we give the materialists their external bodies, they by their own confession are never the nearer knowing how our ideas are produced: since they own themselves unable to comprehend in what manner body can act upon spirit, or how it is possible it should imprint any idea in the mind."
— Berkeley, George (1685-1753)
(Part I, §19, p. 49)
See also Tonson's London edition: A Treatise Concerning the Principles of Human Knowledge. Wherein the Chief Causes of Error and Difficulty in the Sciences, with the Grounds of Scepticism, Atheism, and Irreligion, are Inquired Into. First Printed in the Year 1710. To Which are Added Three Dialogues between Hylas and Philonous, in Opposition to Scepticks and Atheists. First Printed in the Year 1713. Both Written by George Berkeley, M. A. Fellow of Trinity-College, Dublin (London: Jacob Tonson, 1734). <Link to ECCO>
Text from Past Masters digitized version, based on second edition of 1734. From The Works of George Berkeley, ed. T. E. Jessop and A. A. Luce, vol. ii (Desirée Park: Thomas Nelson, 1979).