David Hartley's Newtonian neuropsychology

David Hartley's association psychology has been immensely influential. His vibrationist neurophysiology has, in contrast, been largely overlooked and forgotten. Hartley's vibration theory is examined. On the one hand it is shown how closely it is related to Sir Isaac Newton's mathematical physics and on the other how well it complements the association theory. The vibration theory, indeed, strongly influenced Hartley's associationist psychology and hence is of more than merely antiquarian interest. Although Hartley's understanding of the central nervous system has long been superseded, his general ideas prefigure some aspects of contemporary neurophysiology and philosophy of mind and thus provide a further reason for rescuing his vibrationism from oblivion.