investigate the curves which bodies would describe if acted on by forces which, so far as we are aware, have no patterns in nature. 2. Real existences: i. e. objects existing without the mind, corresponding to ideas within it (p).

§ 6. With regard to intensity of persuasion: the faculties of the human mind are comprehended in the genera knowledge and judgment (g). 1. By "knowledge," strictly speaking, is meant an actual perception of the agreement or disagreement of any of our ideas (1) ; and it is only to such a perception that the term "certainty" is properly applicable (s). Knowledge is intuitive when this agreement or disagreement is perceived immediately, by comparison of the ideas themselves; demonstrative, when it is only perceived mediately, i. e. when it is deduced from a comparison of each, with intervening ideas which have a constant and immutable connection with them, as in the case of mathematical truths of which the mind has taken in the proofs. And, lastly, when, through the agency of our senses we obtain a perception of the existence of external objects, our knowledge is said to be sensitive (t). But knowledge and certainty are constantly used in a secondary sense, which it is important not to overlook; viz. as synonymous with settled belief or reasonable conviction as when we say that such a one received stolen goods, knowing them to have been stolen; or that we are certain, or morally certain, of the existence of such a fact, &c. (u).

§ 7. 2. "Judgment," the other faculty of the mind, though inferior to knowledge in respect of intensity of persuasion, plays quite as important a part in human speculation and action, and, as connected with jurisprudence, demands our attention even more. It is the faculty by which our minds take ideas to agree or disagree, facts or propositions to be true or false, by the aid of intervening ideas whose connection with them is either not constant and immutable, or is not perceived to be so (a). The foundation of this is the probability or likelihood of that agreement or disagreement, of that truth or falsehood, deduced or presumed from its conformity or repugnancy to our knowledge, observation, and experience (y).

Judgment is often based on the testimony of others, vouching their observation or experience (2); but this is clearly a branch of the former, as our belief in such cases rests on a presumption of the accuracy and veracity of the narrators.

§ 8. Actual knowledge and certainty extending a comparatively little way, men are compelled to resort to judgment, and to act on probability, in by far the greater number of their speculations, as well as in the transactions of life, both ordinary and extraordinary, trivial and important (a). The faculty of judgment is conversant not only about matters of fact, which, falling under the observation of our senses, are capable of being proved by human testimony, but also about the operations of nature, and other things beyond the discovery of our senses (b); and it thus embraces the enormous class of subjects investigated by analogy and induction (c). But here it is important to remark, that on the same matter one man may have knowledge and certainty, while another has only judgment and probability; as when a man, either from ignorance of mathematical. principles or disinclination to go through the proofs, receives a mathematical truth on the testimony of one who comprehends it; in this case he has only got moral evidence of that truth, while his informant has demonstrative proof (d).

§ 9. Another great distinction between knowledge and judgment remains to be pointed out. The former is, as we have seen, reducible to three kinds (e); but to classify the degrees of persuasion resulting from judgment is wholly beyond human power; for the extent to which facts or propositions may be in conformity with our antecedent knowledge, observation, or experience, necessarily varies ad infinitum. An attempt has been made to express some of the shades of judgment by the terms assurance, confidence, confident belief, belief, conjecture, guess, doubt, distrust, disbelief, &c. (ƒ).

§ 10. The word PROOF seems properly to mean anything which serves, either immediately or mediately, to convince the mind of the truth or falsehood of a fact or proposition (g); and as truths differ,

(z) Locke, bk. 4, ch. 15, § 4.

(a) Id. ch. 14, § 1; Butler's Analogy of Religion, Introduction; 3 Bentham's Judicial Evidence, 351; Gilb. Ev. 3, 4, 4th ed.

(b) Locke, bk, 4, ch. 16, §§ 5 and 12. (c) Id. § 12, and Bonnier, Traité des Preuves, §§ 9 et seq., 2d ed.

(d) Locke, bk. 4, ch 15, § 1; and ch. 14, § 3; 1 Greenl. Ev. § 1, note (1), 7th ed.

(e) Supra, § 6.

(f) Locke, bk. 4, ch. 16, §§ 6-9.

(g) Domat, Les Lois Civiles dans leur Ordre Naturel, part. 1, liv. 3, tit. 6; Bonnier, Traité des Preuves, § 5, 2d ed.

the proofs adapted to them differ also (h). Thus the proofs of a mathematical problem or theorem are the intermediate ideas which form the links in the chain of demonstration: the proofs of anything established by induction are the facts from which it is inferred, &c. and the proofs of matters of fact in general are our senses, the testimony of witnesses, documents, and the like. "Proof" is also applied to the conviction generated in the mind by proof properly so called (i).

§ 11. The word EVIDENCE signifies, in its original sense, the state of being evident, i. e. plain, apparent, or notorious (k). But by an almost peculiar inflection of our language (1), it is applied to that which tends to render evident or to generate proof. This is the sense in which it is commonly used in our law books, and will be

(h) Domat, in loc. cit.

(i) Matthæus de Probationibus, c. 1, n. 1; Huberus, Prælectiones Juris Civilis, lib. 22, tit. 3, n. 2; 1 Greenl. Ev. § 1, 7th ed.

(k) Johns. Dict. The Latin "evidentia," and the French "évidence," are commonly restricted by foreign jurists to those cases where conviction is produced by the testimony of our senses. See Quintilian, Inst. Orat. lib. 6, c. 2; Calvin,

Lexic. Jurid.; Steph. Thesaur. Ling. Lat.; Domat, Lois Civiles, part 1, liv. 3, tit. 6; Bonnier, Traité des Preuves, §§ 6, 8, 9, 82, &c., 2d ed. All relating to evidence, as the term is used in English law, is treated of by the Civilians and Canonists under the head "probatio," and by the French writers under that of “preuve.”

(7) It has the same meaning in Norman-French; see int. al. T. 18 Edw. II. 614, tit. Replegg.; 9 Edw. III. 5, 6, pl. 11.

1 Evidence defined. Greenleaf (1 Greenl. Ev. § 1) defines as follows: "Evidence, in legal acceptation, includes all the means by which any alleged matter of fact, the truth of which is submitted to investigation, is established or disproved." This definition apparently includes too much; as pointed out by Bentham, evidence is all legal means, exclusive of mere argument. Conf. Wills. Circ. Ev. 2; 1 Stark. Ev. 10; 1 Phil. Ev. 1; 1 Whar. Ev. § 3. Mr. Justice Stephen defines evidence (Steph. Dig. Law Ev. Art. 1) as follows: "Evidence means (1.) statements made by witnesses in court under a legal sanction, in relation to matters of fact under inquiry; (2.) documents produced for the inspection of the court or judge." As to what evidence is admissible, see § 33, n. 1, infra.

"Fact." All such definitions, including that of Bentham indorsed by Best in § 11, infra, labor under the disadvantage that no accurate definition has yet been given of what is legally understood by the term "fact," used in defining the term "evidence." Mr. Justice Stephen (Dig. Law Ev., 3d ed., Art. 1) has abandoned the attempt at definition contained in his two earlier editions, and contents himself with the statement that "fact" "includes the fact that any mental condition of which any person is conscious exists." Wheelden v. Wilson, 44 Me. 1. For Best's definition of "fact," see § 33, infra. The term "matter of fact" resolves itself, therefore, into a convenient phrase, only intelligible when useless, and vaguely opposed to the equally vague "matter of law," from which it could accurately be distinguished simply by drawing a list. Conf. § 82, n. 2, infra. The following distinction has, however, been plausibly taken. “Matter of fact" is anything which is the subject of testimony (see Morgan's Best, § 33, n. 1); "matter of law" is the general law of the land, of which courts will take judicial cognizance. (See §§ 33, 253, n. 1, (6), infra.)

used throughout this work. Evidence, thus understood, has been well defined, any matter of fact, the effect, tendency, or design of which is to produce in the mind a persuasion, affirmative or disaffirmative, of the existence of some other matter of fact (m). The fact sought to be proved is termed the "principal fact": the fact which tends to establish it, "the evidentiary fact" (n). When the chain consists of more than two parts, the intermediate links are principal facts with respect to those below, and evidentiary facts with respect to those above them. Such we propose to call "subalternate" principal and evidentiary facts.

§ 12. Confining ourselves henceforward to truths of fact, the proper object of the present treatise, we shall first direct attention to some divisions of them, which, as connected with jurisprudence especially, it will be convenient to bear in mind. In the first place, then, facts are either physical or psychological (o). By "physical facts" are meant such as either have their seat in some inanimate being, or if in one that is animate, then not by virtue of the qualities which constitute it such; while "pyschological facts" are those which have their seat in an animate being, by virtue of the qualities by which it is constituted animate. Thus, the existence of visible objects, the outward acts of intelligent agents, the res gesta of a lawsuit, &c., range themselves under the former class: while to the latter belong such as only exist in the mind of an individual; as, for instance, the sensations or recollections of which he is conscious, his intellectual assent to any proposition, the desires or passions by which he is agitated, his animus or intention in doing particular acts, &c. Psychological facts are obviously incapable of direct proof by the testimony of witnesses, their existence can only be ascertained either by confession of the party whose mind is their seat (p), — "index animi sermo" (q), or by presumptive inference from physical facts (r).

§13. There are two other divisions of facts which deserve to be noted. One is, that they are either events or states of things (s). By an "event" is meant some motion or change, considered as having

(m) 1 Benth. Jud. Ev. 17. "Evidence," Evidentia, signifies generally any proof, be it testimony of men, records, or writings. Cowel's Interpreter; and Les Termes de la Ley. See Co. Litt. 283 a. (n) 1 Benth. Jud. Ev. 18. (0) Id. 45.

(p) Mascardus de Probationibus, Concl. 309; 1 Benth. Jud. Ev. 82, 145; 3 id. 6. (g) 5 Co. 118 b.

(r) Mascard. de Prob. Concl. 94; 1 Benth. Jud. Ev. 82, 145; 3 id. 6. (s) 1 Benth. Jud. Ev. 47.

come about either in the course of nature, or through the agency of human will; in which latter case it is called "an act,” or an action." The fall of a tree is "an event," the existence of the tree is "a state of things"; but both are alike "facts" (t). The remaining division of facts is into positive or affirmative, and negative (u): a distinction which, unlike both the former, does not belong to the nature of the facts themselves, but to that of the discourse which we employ in speaking of them (x). The existence of a certain state of things is a positive or affirmative fact, the non-existence of it is a negative fact. But the only really existing facts are positive ones, for a negative fact is nothing more than the non-existence of a positive fact; and the non-existence of a negative fact is equivalent to the existence of the correspondent and opposite positive fact (y).

§ 14. Our persuasion of the existence or non-existence of facts has its source, or efficient cause, either in the operation of our own perceptive or intellectual faculties, or in the operation of the like faculties on the part of others, evidenced to us either by discourse or deportment. The former of these may be called evidence ab intra ; the latter, evidence ab extra (z). The immense part which evidence ab extra bears in forensic procedure, as well as in almost everything else, makes it advisable that we should consider, somewhat at large, the grounds of belief in human testimony, and the dangers to be avoided when dealing with it.

§ 15. The existence of a strong tendency in the human mind to accept as true what has been related by others is universally admitted, and is confirmed by every day's observation; and it may be laid down as equally certain, that one cause of this tendency is our experience of the great preponderance of truth over falsehood, in human testimony taken as a whole. But whether this is the sole cause has given rise to difference of opinion. Writers on natural law describe man as endowed by nature with a sort of moral instinct, which prompts him to act in certain cases where vigor and expedition are required, and where the faculties of reason and reflection are either immatured, or, if matured, would be too slow (a): and most authors think that a tendency to believe the statements of others is to be found among the operations of this instinct. Man,

(t) 1 Benth. Jud. Ev. 48. (u) Id. 49.

(x) Id.

(y) Id. 49, 50.

(z) Id. 51, 52.

(a) Burlamaqui, Principes du Droit de la Nature et des Gens, pt. 2, ch. 3.