specifick difference, which distinguishes wine from cider and perry, which are also juices.* CHAPTER SECOND. DEFINITION AND DIVISION. 39. Definitions are usually distinguished into two kinds; one nominal, or of the name ; the other real, or of the thing. A definition of the name is merely a specification of the object, to which a name is applied. A definition of the thing is properly an analysis of a thing, or an enumeration of its principal attributes. 40. Words, which stand for indivisible objects, admit only of nominal definitions. These are sometimes sufficiently explained by intelligible synonymous words; thus being denotes existence; identity implies sameness. Those, which stand for simple qualities of body, may be defined by referring to the subjects, in which those qualities reside; and those, that denote mental states, by describing the occasions, on which they are produced. Thus yellow is the * Locke, Essay on the Understanding, b. iii. ch. 3. Reid, Essays, vol. ii. essay v, ch. 1. Belsham, Logick, part i. sect. 4 and 5. Kirwan, Logick, part i. cb. 2, sect. 2. colour of gold or saffron. Surprise is the passion, or state of mind, produced by the perception of some new or uncommon object. 41. A real definition leads us to a knowledge of the nature of a thing, by enumerating its most essential modes and properties. Thus a circle is a figure, whose circumference is, in every part, equally distant from the centre. Injustice is an intentional violation of another's rights. Real definition includes the nominal; for an explanation of the nature of any thing necessarily fixes the signification of the name, by which it is called. Natural substances, and all compound beings, whether real or imaginary, are susceptible of real definitions. 42. Logicians divide a definition into two parts, which are called genus and difference. If the thing to be defined be in any degree general, that is, expressed by a generick term, the definition will be made up of the proximate genus and the specifick difference. Thus bird is an animal, which has wings, feathers, and a hard, glossy bill. Animal is the proximate genus, denoting what bird has in common with horse, deer, elephant; the other terms denote the specifick difference; for they point out the properties, which distinguish bird from every other species of animals. So square is a figure, which has four equal sides, and four right angles. Figure is the proximate genus; the other terms make the specifick difference. 43. If the thing to be defined be an individual, having a proper name, the definition will consist of the species and an enumeration of so many properties, as will distinguish that individual from all others of that species. Thus Mercury is the planet nearest the sun. Planet is the lowest species; nearest the sun is the circumstance, which sufficiently marks a difference between Mercury and the other planets. 44. There are many words in every language, which cannot be defined, because they have no uniform signification affixed to them. The, this, that, which, such, every, good, bad, desirable, and the like, are nearly insignificant sounds, till they are applied to particular things, from which they borrow a sort of local or temporary meaning and they often signify different things, when applied to different subjects. Good, applied to a soldier, means courage; to a Christian, piety; to a physician, skill; to a horse, strength; to a knife, sharpness. 45. Words of this description, which have no uniform signification affixed to them, are wholly employed in the definition of other terms. The definitive particles have no other use, than to restrain the latitude of general terms. For example, the man, this horse, that tree, such an object. Here the names man, horse, tree, and object, which represent whole classes of things, are restrained, by the words the, this, that, and such, to certain individuals, with which we are supposed to be already acquainted. Again, a wide river, a severe winter, a delightful prospect. The terms river, winter, and prospect, are general; wide, severe, and delightful, denote specifick differences. Whereever the latitude of a general word is restrained by a definitive, or a quality is attributed to a subject, we may recognise the two essential parts of a definition, namely, genus and differ ence. 46. Division is the explication of any whole by the enumeration of its component parts. Thus a tree is divided into trunk, roots, and insect. branches; animal, into beast, bird, fish, and The term, division, is applicable to the resolution of a treatise or discourse into its several heads or branches; also, to the consideration of an equivocal word in reference to its different significations. The members of a division should exhaust the subject divided; and they should be so opposed, that one will not be contained in another. The parts, into which any thing is first divided, should be the largest and most general. The resolution of one of these parts into others, more minute, is called subdivision. So a year is first divided into months. Month is then subdivided into weeks; week, into days, and so on. Needless subdivisions should be avoided, as they burden the memory, and introduce confusion.* CHAPTER THIRD. GENERAL DESCRIPTION OF PROPOSITIONS. 47. A proposition is a verbal representation of some perception, act, or affection of the mind. * Locke, Essay, b. iii. Watts, Logick, part i. Kirwan, Logick, part i. |