In his day and for some years into the 19th century, he was regarded as more important than David Hume. He advocated direct realism, or [common sense realism]?, and argued strongly against the so-called [Theory of Ideas]? advocated by John Locke, Descartes, and (in varying forms) nearly all [Early Modern philosophers]? who came after them.
His reputation waned after attacks on the [Scottish School of Common Sense]? by Immanuel Kant and John Stuart Mill. His reputation has arisen again in the wake of the advocacy of common sense as a philosophical method or criterion by G. E. Moore early in the century, and more recently due to attention given Reid by contemporary philosophers such as William Alston and [Alvin Plantinga]?.
He wrote a number of important philosophical works, including [Inquiry into the Human Mind on the Principles of Common Sense]?, the [Essays on the Intellectual Powers of Man]?, and the [Essays on the Active Powers of Man]?.