and regulate my conduct by, without dan ger of any inconvenience. It is not eafy on this fubject to avoid identical expreffions. I am not certain that I have been able to avoid them. And perhaps I might have expreffed my meaning more fhortly and more clearly, by faying, that I account That to be truth which the constitution of my nature determines me to believe, and That to be falfehood which the conftitution of my nature determines me to difbelieve. Believing and difbelieving are fimple acts of the mind; I can neither define nor defcribe them in words; and therefore the reader muft judge of their nature from his own experience. We often believe what we afterwards find to be falfe; but while belief continues, we think it true; when we discover its falfity, we believe it no longer. Hitherto we have ufed the word belief to denote that act of the mind which attends the perception of truth in general. But truths are of different kinds; fome are certain, others only probable; and we ought not to call that act of the mind which attends the perception of certainty, and and that which attends the perception of probability, by one and the fame name, Some have called the former conviction, and the latter affent. All convictions are equally ftrong; but affent admits of innumerable degrees, from moral certainty, which is the highest degree, downward, through the several stages of opinion, to that fufpense of judgement which is called doubt. We may, without abfurdity, speak of probable truth, as well as of certain truth.. Whatever a rational being is determined, by the conftitution of his nature, to admit as probable, may be called probable truth; the acknowledgement of it is as univerfal as rational nature, and will be as But, in this inquiry, we permanent. propofe to confine ourselves chiefly to that kind of truth which may be called certain, which enforceth our conviction; and the belief of which, in a found mind, is not tinctured with any doubt or uncertainty. The investigation and perception of truth is commonly afcribed to our rational faculties and these have by fome been reduced to two; Reason, and Judgement; the former being fuppofed to be converfant about certain truths, the latter chief ly ly about probabilities. But certain truths are not all of the fame kind; fome being fupported by one fort of evidence, and others by another: different energies of the understanding must therefore be exerted in perceiving them; and thefe different energies must be expreffed by different names, if we would speak of them distinctly and intelligibly. The certainty of fome truths, for inftance, is perceived intuitively; the certainty of others is perceived, not intuitively, but in confequence of a proof. Most of the propofitions of Euclid are of the latter kind; the axioms of geometry are of the former. Now, if that faculty by which we perceive truth in confequence of a proof, be called Reafon, furely that power by which we perceive felf-evident truth, ought to be diftinguished by a different name. It is of little confequence what name we make choice of, provided that in chufing it we depart not from the analogy of language; and that, in applying it, we avoid equivocation and ambiguity. Some philofophers of note* have given the name of Common Senfe to that faculty by which we Buffier, Dr Reid, &c. perceive perceive felf-evident truth; and, as the term feems proper enough, we fhall adBut in a fubject of this kind, opt it. there is great danger of our being impofed upon by words; we cannot therefore be too much upon our guard against that fpecies of illufion. We propose to draw fome important inferences from this doctrine of the diftinction between Reafon and Common Senfe. Now thefe words are not always used in the strict fignification we have here affigned them: let us therefore take a view of all the fimilar fenfes in which they are commonly used, and let us explain more particularly that fenfe in which we propofe to use them; and thus we fhall take every method in our power to fecure ourselves against the impropriety of confounding our notions by the use of ambiguous and indefinite language. These philological difcuffions are indeed no part of philofophy; but they are very neceffary to prepare us for it. "Qui ad interpre"tandam naturam accefferit," fays Lord Verulam, verborum mixtam naturam, et juvamenti et nocumenti imprimis par"ticipem, diftincte fciat *. 99 De interpretatione Naturæ, fent. 9. This diftinction between Common Senfe and Reafon is no modern difcovery The ancient geometricians were all acquainted with it. Ariftotle treats of felfevident principles in many parts of his works, particularly in the fourth book of his Metaphyfics, and in the first book of his latter Analytics. He calls them, Axioms or Dignities, Principles, and Common See The room of the Greek Stoics feems to mean that benevolent affection which men owe to fociety and to one another. Some of the modern moralifts have called it the l'ublic Senfe. But the notion or idea we mean to exprefs by the term Common Senfe is quite different. The Senfus Communis of the Latins hath feveral fignifications. 1. It denotes this. Public Sense, or solvovanμoovn. Shatefbury's Elay on the freedom of wit and humour, part 3. fect. 1. Note. 2. It denotes that experience and knowledge of life which is acquired by living in fociety. Thus Horace feems to use it, lib. 1. fatir. 3. lin. 66. And thus Quintilian, fpeaking of the advantages of a public education: "Senfum ipfum qui communis dicitur, ubi difcet, cum fe a congreffu, qui non hominibus folum, "fed mutis quoque animalibus naturalis eft, fegregarit?" Lib. 1. cap. 2. 3. It feems to fignify that inftinctive perfuafion of truth which arifes from intuitive evidence, and is the foundation of all reasoning: "Corpus enim per fe communis deliquat effe E Lucretius, lib. 1. ver. 423. Sentiments; |