Thomas Reid (1710-1796) is increasingly seen as a philosopher of lasting importance and as a central figure in the Scottish Enlightenment. Intellectual Powers is his greatest work. It covers far more philosophical ground than the earlier, more popular Inquiry. Intellectual Powers and its companion volume, Essays on the Active Powers of Man, constitute the fullest, most original presentation of the philosophy of Common Sense. In this work Reid provides acutely critical discussions of an impressive array of thinkers but especially of David Hume. In Reid's view, Hume had driven a deep tendency in modern philosophy to its ultimate conclusion by creating a phantom-world of "ideas" that spring from objects of observation. On this account, the self is a conglomeration of perceived ideas; the will, as the source of action, is nothing but the balance of passionate impulses.Reid's Common Sense philosophy responds to these problems by suggesting that skeptics such as Hume unavoidably affirm what they purport to deny-namely, the existence of a stable external world, of other minds, of the continuity of their own minds, and of their own and other people's ability to ascribe and accept responsibility for actions. We can understand all of these things by proper empirical observation and philosophical analysis of the activity of the mind. Reid's major positive contribution to philosophy is a detailed account of the various innate powers of the mind. This is the only properly established text. It is accompanied by Reid's manuscript lectures on the nature and immortality of the soul as well as helpful editorial annotations and an introduction, making it useful to a wide variety of readers.