thus presented, we without doubt admit. If I see a house fall, I am at once immediately assured of the catastrophe. But if some one tells me the thing has happened, various con'siderations may warrant the conclusion that my informant is worthy of credit, and therefore I infer that the house has fallen.

Again, we feel certain emotions in our mindsanger, hope, fear, sorrow, joy-of which we are at once conscious. But if I observe the gestures of an angry man, the contortions of his countenance, the glare of his eyes, or if I hear his words and mark their violence, I infer from these outward signs that he is really angry.

Also memory preserves in our minds the truths which we have imbibed. I know of my own knowledge that at a certain time yesterday I was hungry. I knew it at the time, and as I have the power of memory, the knowledge remains. But I infer, that an hour ago my informant told me truly there had been a shipwreck, for even at the time he told me I was obliged to infer the truth.

Again, according to Mill (vol. I. p. 9), "it is universally allowed, that the existence of matter or of spirit, of space or of time, is in its nature unsusceptible of being proved." These things we know immediately.

In regard to some truths, it may perhaps be controverted, whether they are to be considered as known directly, or by inference, or possibly in both ways. It seems however unnecessary, especially at the present stage of our inquiry, to pursue these topics further. Suffice it to remark, that much the greater portion of our knowledge depends upon inference.* The term "self-evident" has been applied to truths which are known immediately. All truths however which we admit must have something that shews them to the human mind, and in this they differ from such truths as are hidden from our view. On what ground soever, therefore, propositions claim assent, we are still at liberty to adhere to our definition; i.e. whatever shews us that things are true, may be called the evidence of such truth.

*"The power of reasoning (says Reid) is justly accounted one of the prerogatives of human nature, because by it many important truths have been and may be discovered, which without it would be beyond our reach: yet it seems to be only a kind of crutch to a limited understanding. We can conceive an understanding superior to human, to which that truth appears intuitively, which we can only discover by reasoning."

CHAPTER IV.

VARIOUS DEGREES OF EVIDENCE, SHEWING THAT THINGS HAVE BEEN, ARE, WILL BE.

In their considerations of abstract truth, men are sometimes apt to imagine that the constitution of nature might have been different from what it is evidence (they think) might in all cases have shewn them with absolute demonstration, that things have been, are, will be, have not been, are not, will not be: or, in other words, truth and falsehood might have been always plain, and error physically impossible. But experience shews that such is not the condition of man. Our faculties are limited. We learn things by evidence of various degrees in strength and cogency. It is physically possible, that even in cases where we rely upon the evidence of our senses, we may be mistaken: for sometimes the sensibility of the organs themselves is impaired; at other times they are rendered inefficient by the novelty and strangeness of the circumstances in which their powers are required. So again in regard to inference: I

may confide in the veracity of a witness, still I know that men do not always speak truth. Hence, though we ever desire great strength of proof, and sometimes indeed with a morbid craving, our circumstances nevertheless are such that we are obliged to estimate inferior degrees of evidence: and how much soever we may wish to be at once assured that things are certainly true or certainly false, we yet weigh, laboriously it may be and with diligence, that which shews they are probably true, or doubtful, or probably false.

There is one species of evidence which forces conviction with wonderful power. Thus, for instance, if it be granted that the definitions in Euclid's Elements are consistent, and the axioms true, we infer the equality of the angles at the base of an isosceles triangle with overwhelming and irresistible strength: every reasonable mind is at once compelled to recognition, and perceives that no objection can for an instant stand.* The process of reasoning thus employed is called Mathematical.

It is certain that those things which we receive directly,† are admitted with a very high

*"Every link (it is said) of the Mathematical chain is of equal, that is, the utmost strength."

See last Chapter.

degree of assurance. "What one sees or feels, whether bodily or mentally, one cannot but be sure that one sees or feels. No science is required for the purpose of establishing such truths; no rules of art can render our knowledge of them more certain than it is in itself. There is no logic for this portion of our knowledge."

Again, the testimony of witnesses is of remarkable cogency. Men naturally speak the truth, unless there be some motive inducing them to lie. But in any given case I may know the character of a witness, and the circumstances under which he delivers his testimony. I may hence be altogether convinced that his statements are true, more especially if essentially probable, or confirmed by independent witnesses. What but the force of united testimony assures us that Louis XVI., king of France, was beheaded? If the general of an army employs a guide, who knows that if he misleads, he will instantly be put to death, such knowledge is a security more or less powerful for his truth. If a minister of the British Crown states in parliament, that he has just received intelligence of a serious insurrection in some

* See Mill again.