18th- and early 19th-century Scottish school of Thomas Reid (Reid, Thomas), Adam Ferguson, Dugald Stewart, and others, who held that in the actual perception of the average, unsophisticated man, sensations (sensation) are not mere ideas or subjective impressions but carry with them the belief in corresponding qualities as belonging to external objects. Such beliefs, Reid insisted, “belong to the common sense and reason of mankind”; and in matters of common sense “the learned and the unlearned, the philosopher and the day-labourer, are upon a level.”

The philosophy of common sense developed as a reaction against the skepticism of David Hume and the subjective idealism of George Berkeley, both of which seemed to issue from an excessive stress on ideas. This provided what seemed to the common sense philosophers to be a false start leading from fundamental premises to absurdities. This false start stemmed from René Descartes and John Locke inasmuch as they gave to ideas an importance that inevitably made everything else succumb to them.

From 1816 to 1870 the Scottish doctrine was adopted as the official philosophy of France; and in the 20th century the teaching of G.E. Moore (Moore, G E), a founding father of analytic philosophy (especially in his “Defence of Common Sense,” 1925), convinced many British and American philosophers that it was not their business to question the common certainties but rather to analyze them.