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ence, but to carry on the figurative mode of expression, and regarding truth and knowledge as an edifice, if any contest should arise about the construction of the parts; as for instance, whether they were arranged according to just proportions, and upon the true principles of architecture, these general maxims night be appealed to as acknowledged standards, in order to decide the controversy. The true vincula of the chain, would be those particular self-evident proposi. tions that must enter into all reasoning which is conclusive, but not these general axioms or maxims. To put the matter beyond all dispute by an illustration. In the usual mode of proving that in a rectangular triangle, the square of the hy. pothenuse is equal to the sum of the squares of the other two sides, the square formed upon the hypothenuse is divided by lines into two parallelograms, each of which is proved to be equal to corresponding squares, erected upon the sides including the right angle. Now as the two parallelograms, composing the square, are proved to be equal severally to the smaller squares erected upon the other sides, it is concluded, that when added together they will be equal to the sum of these squares, since the general axiom is not to be denied, that if equals be added to equals the sum will be equal. This is undoubtedly true. But in this case we say, that there was no necessity for a recurrence to the general maxim, to enable the understanding to perceive the justness of the conclusion. For after we have proved that the one parallelogram, into which the larger square is divided, is equal to one of the smaller squares, and the other parallelogram is equal to the other square, the understanding, without any aid from a general principle, goes irresistibly to the conclu. sion, that if the parallelograms be added together they will be equal to the smaller squares added together, or in other words, the square of the hypothenuse, is equal to the sum of the squares of the other sides. It will here be distinctly perceived, that the progress of the understanding is to arrive at the conclusion by means of the particular self-evident truth or axiom, and not by means of the general; and the general is only appealed to on account of the authority which it has acquired in the mind, from its familiarity with it as one of the standards of truth. We do not maintain that all science must not rest upon axiomatic truth, for this is certain, but that no science rests upon general, self-evident truths or axioms. The mind, in prosecuting its inquiries in all the branches of science, grounds all its conclusions upon those first principles, or particular self-evident propositions, which belong to the subject it is investigating, and these are the sources from which the general maxims are derived, and not the particulars from the generals.
Testimony a Ground of Hunian Knowledge
The third ground of human knowledge is found in the testimony of others. Our philosopher before mentioned, after he had learnt to extend his researches by experience and observation, and to trace the natural connection of his ideas and the immutable relations of things, as soon as he began to mingle in the intercourses of life, would discover, that so short was his own life, and so limited his own experience, he must trust to the reports of others for a large proportion of information, in which he found it necessary to repose confidence. Hence a new source of knowledge is opened to him. Mr. Locke, indeed, would not denominate that information which we obtain in this way knowledge, but divides all our knowledge into the intuitive, sensitive, and demonstrative, or that which we derive from intuition, and is self evident; that which we derive from experience, and rests upon the evidence of the senses; and that which we derive from reasoning, and which is demonstrative. According to him, therefore, we cannot be said in the highest sense of the word, to know what is only conveyed to us by the reports of others; but can be only rationally assured of its truth from unimpeachable testimony. Perhaps, this representation of the matter is just, and this the true signification of the term knowledge, according to its technical and philosophical import; but there is a more enlarged sense of the word, which is the meaning annexed to it, in ordinary discourse, that seems liable to no solid objection. In this latitude of ex. pression we are said to know that Julius Cæsar was slain in the Senate House, that Regulus advised the Roman Senate against concluding a peace with Carthage, and matters of a similar nature. This is the prevalent phraseology of writers, and we can perceive no injury, or disadvantage likely to result to science from its use, when rightly understood.
Under this view of the subject, and indulging this latitude of expression, we have assigned testimony as the third ground of human knowledge. Our next step, therefore, in the plan we are pursuing, is to state the evidence of testimony, and ascertain when it is to be confided in, and when rejected as a foundation of assent,
The first question which arises in the science of the human mind, on this point, is; how do we come to repose confidence in the testimony of others? Is it done instinctively or acquired by experience? And as to this point, I think there can scarcely be entertained a doubt that, in the original conformation of our nature, we are so modelled by the Creator, as that we do instinctively and prior to reflection, feel an inclination to give credit to the reports made to us by others in matters of fact. In this respect, as in others, the great Contriver has exhibited a wonderful correlation, and adaptation of one portion of the system to another. As he has indubitably written upon the hearts of all mankind a law of probity, which imperiously exacts of them to prefer truth to falsehood; so he has impressed upon them also another corres. ponding law, which leads them to give credit to the testimony of each other. This original tendency in children from the earliest period is strengthened by experience, from finding daily a correspondence or conformity between facts and events related to them by their parents, nurses, and companions, and the actual state of things. The only ground however, of a rational corfidence in the testimony of others, is