Reid, Thomas (1710–1796)
Authors: Gallie Roger 
Published: September 2018

Thomas Reid, born at Strachan, Aberdeen, was the founder of the Scottish school of Common Sense philosophy. Educated at Marishal College, Aberdeen, he taught at King’s College, Aberdeen until appointed professor of moral philosophy at Glasgow. He was the co-founder of the Aberdeen Philosophical Society or ‘Wise Club’, which counted among its members George Campbell, John Stewart, Alexander Gerard and James Beattie. His most noteworthy early work, An Inquiry into the Human Mind: Or the Principles of Common Sense attracted the attention of David Hume and secured him his professorship. Other important works are Essays on the Intellectual Powers of Man (1785) and Essays on the Active Powers of the Human Mind (1788).
Reid is not the first philosopher to appeal to common sense; Berkeley and Butler are notable British predecessors in this respect, in the discussions of perception and of free will respectively. It fell to Reid, however, to collect and systematize the deliverances of common sense – the first principles, upon the acceptance of which all justification depends – and to provide adequate criteria for that status. Reid insists we rightly rely on our admittedly fallible faculties of judgment, including the five senses, as well as memory, reason, the moral sense and taste, without need of justification. After all, we have no other resources for making judgments, to call upon in justification of this reliance. We cannot dispense with our belief that we are continually existing and sometimes fully responsible agents, influenced by motives rather than overwhelmed by passions or appetites. In Reid’s view major sceptical errors in philosophy arise from downgrading the five senses to mere inlets for mental images – ideas – of external objects, and from downgrading other faculties to mere capacities for having such images or for experiencing feelings. This variety of scepticism ultimately reduces everything to a swirl of mental images and feelings. However we no more conceive such images than perceive or remember them; and our discourse, even in the case of fiction, is not about them either. Names signify individuals or fictional characters rather than images of them; when I envisage a centaur it is an animal I envisage rather than the image of an animal. In particular the information our five senses provide in a direct or non-inferential manner is, certainly in the case of touch, about bodies in space.
Reid thus seems to be committed to the position that our individual perceptual judgments are first principles in spite of his admission that our perceptual faculties are fallible. Moreover, moral and aesthetic judgments cannot be mere expressions of feeling if they are to serve their purposes; a moral assessor is not a ‘feeler’. Reid is therefore sure that there are first principles of morals, a view that scarcely fits the extent and degree of actual moral disagreement.
Reid offers alternative direct accounts of perception, conception, memory and moral and aesthetic judgment. He stoutly defends our status as continuing responsible agents, claiming that the only genuine causality is agency and that although natural regularities are held to be causes they cannot be full-blooded causes. Continuing persons are not reducible to material entities subject to laws of nature, (pace Priestley); nor does the proper study of responsible agents belong within natural philosophy. Morals may be adequately systematized on a human rights basis according to which private property is not sacrosanct, once moral judgment is recognised to be based on first principles of morals. Judgments of beauty likewise rest on a body of first principles, even though Reid readily allows that there are no properties that all beautiful objects must have in common.