« PreviousContinue »
tempt: as when they define heat, they say, it is qualitas congregans homogenea & segregans heterogenea, i. e. a quality gathering together things of the same kind, and separating things of a different kind. So they define white, a colour arising from the prevalence of brightness: but every child knows hot and white better without these definitions.
There are many other definitions given by the peripatetic philosophers, which are very faulty by reason of their obscurity; as motion is defined by them the act of a being in power, so far forth as it is in power; time is the measure or number of motion according to past, present, and future; the soul is the act of an organical natural body, having life iu power; and several others of the same stamp.
Rule IV. It is also commonly prescribed among the rules of definition, that it should be short, so that it must have no tautology in it, nor any words superfuous. I confess definitions ought to be expressed in as few words as is consistent with a clear and just explication of the nature of the thing defined, and a distinction of it from all other things beside; but it is of much more inportance, and far better, that a definition should explain clearly the subject we treat of, though the words be many, than to leave obscurities in the seutence, by confining it within too narrow limits. So in the definition which we have given of logic, that it is the art of using reason well in the search after truth, and the communication of it to others, it has indeed many words in it, but it could not well be shorter. Art is the genus wherein it agrees with rhetoric, poesy, arithmetic, wrestling, sailing, building, &c. for all these are arts also : but the difference or special nature of it is drawn from its object, reason; from the act, using it well; and from its two great ends or designs, viz. the search of truth, and the communication of it: vor can it be justly described and explained in fewer ideas.
V. If we add a fifth rule, it must be, that neither the thing defined, nor a mere synonymous name, should make any part of the definition, for this would be no explication of the nature of the thing; and a synonymous word at best could only be a des finition of the name.
SECT. VI.- Observations concerning the Definition of
Things. Before I part with this subject, I must propose several observations, which relate to the definition of things.
Ist Observ. There is no need that in definitions we should be confined to one single attribute or property, in order to express the difference of the thing defined, for sometimes the essential difference consists in two or three ideas or attributes. So a grocer is a man who buys and sells sugar, and plumbs, and spices, for gain. A clock is an engine with weights and wheels, that shews the hour of the day both by pointing and striking: and if I were to define a repeating clock, I must add another property, viz. that it also repeats the hour. So that the true and primary essential difference of some complex ideas, consisting in several distinct properties, cannot be well expressed without conjunctive particles of speech.
2d Observ. There is no need that definitions should always be positive, for some things differ from other's merely by a defect of what others have; as if a chair be defined a seat for a single person, with a back belonging to it, then a stool is a seat for a single person without a back; and a form is a seat for several persons without a back : these are negative dif. ferences. So sin is a want of conformity to the law of God; blindness is a want of sight; a vagabood is a person without a home. Some ideas are negative, and their definitious ought to be so too.
3d Observ. Some things may have two or more definitions, and each of them equally just and good; as a mile is the length of eight furlongs, or it is the third part of a league, Eternal is that which ever was and ever shall be; or it is that which had no be. beginning and shall have no end. *Man is usually defined a rational animal; but it may be much better to define him a spirit united to an animal of such a shape, or an animal of such a peculiar shape united to a spirit, or a being composed of such an animal and a mind.
4th Observ. Where the essences of things are evident, and clearly distinct from each other, there we may be more exact and accurate in the definitions of them; but where their essences approach near to each other, the definition is more difficult. A bird may be defined a feathered animal with wings; a ship may be defined a large hollow building made to to pass over the sea with sails: but if you ask me to define a bat, which is between a bird and a beast, or to define a barge and hoy, which are between a boat and a ship, it is much harder to define them, or to adjust the bounds of their essence. This is very evident in all monstrous births and irregular productions of nature, as well as in many works of art, which partake so much of one species and so much of another, that we cannot tell under which species to rank them, or how to determine their specific difference.
The several species of beings are seldom precisely limited in the nature of things by any certain and unalterable bounds: the essence of many things do not consist in indivisibility, or in one evident indivisible point, as some have imagined; but by various degrees they approach nearer to, or differ more from, others that are of a kindred nature. So (as I have hipted before) in the very middle of each of the arches of a rainbow the colours of green, yellow, and red are sufficiently distinguished; but near the borders of the several arches they run into one another,
• The common definition of man, viz. a rational animal, is 1. Because the animal is not rational; the rationality of man arises from the mind to which the animal is. united. 2. Because if a spirit should be united to a horse and make it a rational being, surely this would not be a man: it is evident therefore that the peculiar shape must enter into the definition of a man lo render it just and perfect; for want of a full de scription thereof all our definitions are defective.
so that you hardly know how to limit the colours, por whether to call it red or yellow, green or blue.
5th Observ. As the highest or chief genuses, viz. being and not being can never be defined, because there is no genus superior to them; so neither can singular ideas or individuals be well defined, because either they have no essential differences from other individuals, or their differences are not known; and, therefore, individuals are only to be described by their particular circumstances: so King George is distinguished from all other men and other kings, by describing him as the first King of Great Britain of the House of Brunswick; and Westminster Hall is described by its situation and its use, &c.
That individual bodies can hardly have any essential difference, at least witbin the reach of our knowledge, may be made thus to appear: Methuselah, when he was nine hundred and sixty years old, and, perhaps, woru out with age and weakuess, was the same person as when he was in his full vigour of manhood, or when he was an infant newly boru ; but how far was his body the same? who can tell whether there was any fibre of his flesh or his bones that continued the same throughout his whole life? or who can determine which were those fibres? The ship in which Sir Francis Drake sailed round the world might be new built and refitted so often, that few of the same timbers remained; and who can say whether it must be called the same ship or no? and what is its essential difference? How shall we defiue Sir Francis Drake's ship, or make a definition for Methuselah ?
To this head belongs that most difficult question, what is the principle of individuation? or what is it that makes any one think the same as it was sometime before? This is too large and laborious an en. quiry to dwell upon it in this place : yet I cannot forbear to mention this hint, viz Since our own bodies must rise at the last day, for us to receive rewards or punishinents in them, there may be, perhaps, some original fibres of each human body, some stamina vitæ, or primeval seed of life, which may remain unchanged through all the stages of life, death, and the grave; these may become the springs and principles of a resurrection, and sufficient to denominate it in the same body. But if there be any such constant and vital atom which distinguish every human body, they are known to God only.
6th Observ. Where we cannot find out the essence or essential difference of any species or kinds of beings that we would define, we must content ourselves with a collection of such chief parts or properties of it as may best explain it, so far as it is known, and best distinguish it from otlier things : so a marigold is a flower which hath many long yellow leaves, round a little knot of seeds in the midst, with such a peculiar stalk, &c. So if we would define silver, we say it is a white and hard metal, next in weight to gold: if we would define an elder-tree, we might say it is one among the lesser trees, whose younger brauches are soft and full of pith, whose leaves are jagged or indented, and of such a particular shape, and it bears large clusters of small black berries : so we must define water, eartb, stone, a lion, an eagle, a serpent, and the greatest part of natural beings, by a collection of those properties, which, according to our observation, distinguish them from all other things. This is what Mr. Locke calls nominal essences, and nominal definitions. Aud indeed since the essential differences of the various natural beings or bodies round about us arise from a peculiar shape, size, motion, and situation of the small particles of which they are composed, and since we have no sufficient method to inform us what these are, we must be contented with such a sort of definition of the bodies they compose,
Here note, that this sort of definition, which is made up of a mere collection of the most remarkable parts or properties, is called an imperfect definition, or a description; whereas the definition is called perfect, when it is composed of the essential difference, added to the general nature or genus.
7th Observ. The perfect definition of any being always includes the definition of the name whereby it