Article abstract: Famous for his criticism of “the way of ideas” and its attendant skepticism, Reid defended “common sense” and human freedom.
Thomas Reid was born into distinguished families. His father and ancestors for several generations had been clergymen in the Church of Scotland. On his mother’s side, the Gregory family included the inventor of the reflecting telescope, two mathematics professors in Scotland, and a professor of astronomy at Oxford University. Reid’s own career alternated between the vocations of pastor and professor.
Reid was home schooled until he entered Marischal College, Aberdeen, at the age of twelve. By the time he graduated four years later, he had embraced George Berkeley’s immaterialist philosophy. Reid trained for five years for the Christian ministry, then took the position of librarian at Marischal College between 1733 and 1737, which allowed him to continue his study of John Locke’s philosophy and Isaac Newton’s physics.
In 1737, Reid became the pastor at New Machar, a rural parish just outside Aberdeen. Because the congregation had little input into his appointment, Reid’s ministry had a troublesome start. He married his sixteen-year-old cousin, Elizabeth, four years later. She helped smooth the situation in New Machar, and the congregation grew to love their pastor and his wife during their ten years of service together. The Reids had nine children, but eight died in infancy and young adulthood. Only a daughter, Martha Carmichael, survived.
Reid was forty-one years old when he accepted the invitation in 1751 to become a regent professor at King’s College, Aberdeen. A regent professor taught a group of college students all their courses for three years, then presented them for graduation. Reid taught the sciences and mathematics for two years. Only in the third year would he teach ethics and philosophy, the subjects on which he published. In 1758, he helped organize the Aberdeen Philosophical Society, affectionately called the Wise Club by the small group of professors and ministers who gathered twice a month at a local pub. Reid’s first book, An Inquiry into the Human Mind on the Principles of Common Sense, grew from his presentations and discussions in that group.
Reid was fascinated by the great Scottish philosopher David Hume’s A Treatise of Human Nature (1739-1740). He pored over it as a young pastor and later reviewed the book intensely with his friends in the Aberdeen Philosophical Society.
Hume claimed in A Treatise of Human Nature that people have only two sorts of knowledge and that both are grounded in perceptions of ideas. One either notices necessary relations between ideas (as when noting that “dolphins are mammals”) or knows that things contingently exist because one perceives ideas of them (as when seeing that “there swims Flipper the dolphin”). The young Reid accepted this view. He was genuinely shocked at the skeptical conclusions that Hume carefully deduced from these apparently simple claims. Hume argued that if people perceive only ideas, then they cannot know any reality that is different and beyond those ideas. Ideas are fleeting and entirely separate from one another, not at all like the enduring objects that people believe to exist and to interact one with another. Consequently, from the experience of ideas, people can give no reason to believe that bodies and minds exist, that God exists, or that anything (or anyone) actually causes any event to occur.
Reid accepted the challenge of explaining how people can know such realities through experience. In An Inquiry into the Human Mind on the Principles of Common Sense, he questioned Hume’s key assumption (which Reid variously termed “the ideal theory” or “the way of ideas”) that people perceive ideas. Reid thought this assumption was the root of skepticism in the work of all modern philosophers (whom he judged to be René Descartes, John Locke, and their followers down to his contemporary, David Hume). People mistakenly accept the ideal theory, Reid said, because they confuse sensation and perception. They mistakenly believe that they perceive their sensations. Reid, therefore, kept these processes separate. Sensations are fleeting and separate episodes in consciousness; they just happen to people. Perceptions, on the other hand, involve acts that people do; usually, perceptions are about things that exist continuously outside consciousness. For example, when people type by touch, their sensations are slight momentary pains. They perceive, however, an enduring three-dimensional keyboard at their fingertips. Reid’s point is that people do not perceive the sensations (unless, as when thinking about this example, they concentrate on those brief pains), but they perceive something outside consciousness, the keyboard. They conceive the keyboard and then have perceptual beliefs about the keyboard existing, being on the desk, having a light key touch, and so on. In other words, the object of perception is not ideas, but an enduring, causally engaged reality outside the perceiver.
Hume had declared that conceptions are copied from prior sensations (for example, one can think of cerulean blue because one has had sensations of the blue sky). Reid’s new position was that conceptions usually are nothing like sensations. The conception of an enduring three-dimensional keyboard is nothing like a momentary pain, but upon feeling the latter, the mind thinks of the former. If (as Reid said) there is no similarity between sensations and objects of perception, why, when people have sensations, do they think of a particular object of perception? That is just...
(The entire section is 2370 words.)