Thomas Reid (1710-1796), Scottish philosopher, and a contemporary of David Hume, was the founder of the so-called Scottish School of Common Sense, and played an integral role in the Scottish Enlightenment. He believed that common sense -- a term he used in a special philosophical sense -- is or at least should be at the foundation of all philosophical inquiry.
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.