A notable exponent of the materialist current of English Enlightenment, H. founded a psychophysical associationism which, in the second half of the 18th century, developed with Priestley into a rigorous mystical materialism. LOCKE, JOHN (v.), H. aimed to reduce the duality of the sources of knowledge to the unity of sensation, eliminating reflection and justifying the relations posited by consciousness among various sensible data by recourse to the law of association. In this way, a path was opened, by means of a physical-mechanical explanation of sensation, to a materialist interpretation of psychic facts. H.’s principal work: Observations on man, his duty, his frame, and his expectations (2 vols., London 1749).
BIBL.: Th. Ribot, Quid D. H. de associatione idearum semerit, Paris 1872; G. S. Bower, H. and J. Mill, London 1881; B. Schoenlaute, H. and Priestley die Begründer des Associationismus in England, Halle 1882; M. Heider, Studien über D. H., Bonn 1913. Vittorio Sainati