Hartley, David (1705–1757)

English philosopher. His reputation was established by his Observations on Man (1749), in which he upheld the theory that the phenomena of the mind, memory, emotions, and reasoning were the direct result of molecular nervous vibrations. A school of thought based upon the theory of association of ideas also derives from his work. Though his system has long been discarded, its main ideas still influence philosophical thought and investigation.

Hartley was born near Halifax, England. He studied medicine and practised as a physician in England at Newark, Bury St Edmunds, London, and Bath.