It may excite some surprise that an Essay on Thought should be connected with the construction of a perspicuous sentence. To explain this conjunction, it may be urged, that there can be no evidence of thought, until it is promulgated by speech or written character: and, on all important occasions, such communications of meaning become absolutely necessary. Acquiescence or dissent may indeed be tacitly conveyed, by holding up the hand, or by ballot, without condescending to offer any verbal reasons for the adoption or rejection of the proposed measure. Affirmation or negation does not in any manner constitute Thought; such determination may result from caprice, from ignorance, or from prejudice, without the slightest consideration. Thought requires some proposition clearly conceived and perspicuously expressed in a sentence; and the clearness of the Thought will be ascertained by the perspicuity of its verbal expression. There may be some difficulty respecting the precise meaning of individual words, arising from the corruptions of the ignorant; but more especially from the perversions of writers who have been deemed authorities. This distortion of the original sense, is, in a certain degree, incidental to all living languages, which being in childhood acquired by the ear, the learner is compelled to adopt the signification of words, and employ the current phraseology of those with whom he associates. When he is subsequently taught to speak and write by rule, or grammatically, generally at an age anterior to the exercise of reason, he is coerced to imbibe that which is forced in the way of instruction. Even at a more advanced period the student cannot readily comprehend how a perspicuous sentence is formed by the position of individual words, each bearing a distinct signification, which it is presumed must be the fact: but Mr. DUGALD STEWART, in his _Philosophical Essays_, _p._ 155, has introduced a doctrine entirely opposite to this well-founded position. "So different is all this from the fact, that our words when examined _separately_, are _often_ as completely insignificant as the letters of which they are composed: deriving their meaning _solely_ from the connexion, or relation in which they stand to others."