David Bloor

David Bloor (born 1942) is a British sociologist and philosopher of science, best known as the founder of the Strong Programme in the sociology of scientific knowledge (SSK). His 1976 book Knowledge and Social Imagery remains the manifesto for treating scientific beliefs — true and false alike — as equally requiring social explanation.

Bloor's four tenets — causality, impartiality, symmetry, and reflexivity — were radical because they denied science a special epistemic status. The symmetry tenet, in particular, demanded that the same sociological causes explain the acceptance of oxygen theory and the rejection of phlogiston. Critics argued this conflates the causes of belief with the reasons for truth. Bloor replied that truth itself is a social achievement: what counts as evidence, what counts as demonstration, and what counts as a decisive experiment are all historically variable and institutionally maintained.

Bloor's work transformed the history of science from a chronicle of intellectual progress into an investigation of how knowledge is produced, stabilized, and enforced. The Edinburgh school he helped build remains one of the most influential centers for science studies.