[Footnote: _In parted links_, l. 398. As our ideas consist of successive trains of the motions, or changes of figure, of the extremities of the nerves of one or more of our senses, as of the optic or auditory nerves; these successive trains of motion, or configuration, are in common life divided into many links, to each of which a word or name is given, and it is called an idea. This chain of ideas may be broken into more or fewer links, or divided in different parts of it, by the customs of different people. Whence the meanings of the words of one language cannot always be exactly expressed by those of another; and hence the acquirement of different languages in their infancy may affect the modes of thinking and reasoning of whole nations, or of different classes of society; as the words of them do not accurately suggest the same ideas, or parts of ideal trains; a circumstance which has not been sufficiently analysed.] "Whence REASON'S empire o'er the world presides, And man from brute, and man from man divides; Compares and measures by imagined lines Ellipses, circles, tangents, angles, sines; Repeats with nice libration, and decrees In what each differs, and in what agrees; With quick Volitions unfatigued selects Means for some end, and causes of effects; All human science worth the name imparts, And builds on Nature's base the works of Arts. 410 [Footnote: _Whence Reason's empire_, l. 401. The facility of the use of the voluntary power, which is owing to the possession of the clear ideas acquired by our superior sense of touch, and afterwards of vision, distinguishes man from brutes, and has given him the empire of the world, with the power of improving nature by the exertions of art. Reasoning is that operation of the sensorium by which we excite two or many tribes of ideas, and then reexcite the ideas in which they differ or correspond. If we determine this difference, it is called judgment; if we in vain endeavour to determine it, it is called doubting. If we reexcite the ideas in which they differ, it is called distinguishing. If we reexcite those in which they correspond, it is called comparing.]