arise from sensation; and that reflection is not a distinct source, as Mr. Locke makes it.
Secondly, Mr. Locke ascribes ideas to many words, which, as I have defined idea, cannot be said to have any immediate and precise ones; but only to admit of definitions. However, let definition be substituted instead of idea, in these cases, and then all Mr. Locke’s excellent rules concerning words, delivered in his third book, will suit the theory of these papers.
As to the first difference, which I think may be called an error in Mr. Locke, it is, however, of little consequence. We may conceive, that he called such ideas as he could analyse up to sensation, ideas of sensation; the rest ideas of reflection, using reflection, as a term of art, denoting an unknown quantity. Besides which, it may be remarked, that the words which, according to him, stand for ideas of reflection, are in general words, that, according to the theory of these papers, have no ideas, but definitions only. And thus the first difference is, as it were, taken away by the second; for, if these words have no immediate ideas, there will be no occasion to have recourse to reflection as a source of ideas; and, upon the whole, there is no material repugnancy between the consequences of this theory, and any thing advanced by Mr. Locke.
The ingenious Bishop Berkeley has justly observed against Mr. Locke, that there can be no such thing as abstract ideas, in the proper sense of the word idea. However, this does not seem to vitiate any considerable part of Mr. Locke’s reasoning. Substitute definition for idea in the proper places, and his conclusions will hold good in general.
Natural history is a branch of knowledge, which, at the first view, appears to have a boundless extent, and to be capable of the utmost practical precision and certainty, if sufficient care and industry be employed. And, in fact, the doubts and differences here are not very considerable; they do also grow less and less every day, by the great quantity of knowledge of this kind, which is poured in from all quarters, as learning and inquisitiveness diffuse themselves more and more amongst all nations, and all orders of men.
The materials for natural history, which any single person can collect from his own observation, being very inconsiderable, in respect of those which he wants, he is obliged to have recourse to others; and therefore must depend upon their testimony, just as in civil history. And our assent, in each case, being excited by a variety of concurrent proofs, and of coincident circumstances, transfers part of its authority upon the other. We believe testimony in natural history, because we do in civil, and vice versâ: and have a variety of concurrent confirmations in both cases.
