A philosopher is, no doubt, entitled to examine even those distinctions that are to be found in the structure of all languages... in that case, such a distinction may be imputed to a vulgar error, which ought to be corrected in philosophy.

A new critical edition of these titles plus correspondence and other important material is being brought out by Edinburgh University Press as The Edinburgh Edition of Thomas Reid. Artificial signs signify but they do not express; they speak to the intellect as algebraic characters may do but the passions and the affections and the will hear them not: these continue dormant and inactive till we speak to them in the language of nature to which they are all attention and obedience. Reid notes that current human language contains two distinct elements: first the acoustic element and secondly the meanings which seem to have nothing to do with the sounds as such.

[citation needed] He advocated direct realism or common sense realism and argued strongly against the Theory of Ideas advocated by John Locke René Descartes and (in varying forms) nearly all Early Modern philosophers who came after them. He resigned from this position in 1781.