Thomas Reid
Scottish Enlightenment · Europe · 1710 to 1796
Scottish thinker who answered doubt by arguing that common sense and direct perception are good starting points.
What it is
Thomas Reid (1710 to 1796) was a Scottish philosopher, a minister who became a university professor, and the founder of the Scottish school of common sense. He is best known for his criticisms of Locke, Berkeley and above all Hume, and for his defence of direct perception and of free will.
His central idea is simple to state. We are right to rely on our senses, on basic moral principles and on the fundamental rules of reasoning without first needing a philosophical argument to prove them. The mistake of Hume and his predecessors, Reid thought, was to treat anything that could not be proved by argument as unjustified.
The main ideas
- Common sense. Certain beliefs, such as that the external world exists and that other people have minds, are part of our nature and justified without proof.
- Direct perception. We perceive things themselves, not merely ideas or images in the mind that stand between us and the world.
- Agent causation. Free agents are the real cause of their own actions: they have the power to produce or to hold back an action, and it is up to them.
- A response to scepticism. His approach is one of the great responses to Hume's scepticism, alongside Kant's.
What it looks like in practice
Picture someone who is asked to prove that the table in front of them exists before they may rest a cup on it. Reid would reply that the demand is the mistake: the belief is natural and reliable, and a philosophy that cannot account for it should give way, not the belief. This is an illustration of the idea, not a quotation.
Books and moments
- An Inquiry into the Human Mind is his first major work, on perception and common sense.
- Essays on the Intellectual Powers and Essays on the Active Powers of Man are his larger works on knowledge and on action and morality.
Questions and criticism
- Is common sense an argument or a refusal to argue? Critics say that to appeal to what we naturally believe is to avoid the sceptic's question.
- Does agent causation make sense? His account of free will, in which the agent is itself a cause, has been defended and challenged.
- Whose common sense? The beliefs he treats as universal may be those of his own time and place.
Close neighbours
He answered Hume, and Locke and Berkeley too, and the Scottish school he founded carried on his approach. The pages on Hume, Locke and Berkeley show the thinkers he argued with.
Written by epchē in our own words, and checked against independent sources on 9 October 2026. The sources are listed below.
Who they connect to
Influenced
- Charles Sanders Peirce · Peirce's idea that we should trust common sense, but check it, grew from the Scottish school.
Influenced by
- John Locke · Reid started from Locke's questions about ideas before rejecting the answer.
Reacted against
- David Hume · Reid's Inquiry was written to refute the sceptical results of Hume's account of ideas.
- George Berkeley · Reid attacked the way of ideas that led Berkeley to deny matter.
Other Scottish Enlightenment thinkers
- Francis Hutcheson · 1694 to 1746
- Adam Smith · 1723 to 1790
Sources we used
- Thomas Reid · Stanford Encyclopedia of Philosophy, read on 9 October 2026
- Thomas Reid · Internet Encyclopedia of Philosophy, read on 9 October 2026
- Thomas Reid · New World Encyclopedia, read on 9 October 2026
- Thomas Reid · Wikipedia, read on 9 October 2026