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40. This power of abftraction is of great atisi A carpenter considers a log of wood with regard haruness, firmness, colour, and texture : a philo pher, neglecting these properties, makes the log u dergo a chemical analysis, and examines its taste, smell, and its component principles : the geomet cian ccifines his reasoning to the figure, the lengt breadih, and thickness. In general, every artist, a ftracting from all other properties, confines his obf vations to those which have a more immediate cu nection with his profeflion.
41. It is observed above, p. 401. that there can no such thing as a general idea ; that al} our perce tions are of particular objects, and that our seconda perceptions or ideas must be equally fo. Precise for the same reason, there can be no such thing as abstract idea. We cannot form an idea of a pa without taking in the whole; nor of motion, colou figure, independent of a body. No man will í that he can form any idea of beauty, till he think a person endued with that quality ; nor that he ca form an idea of weight, till he takes under conside ation a body that is weighty. And when he tak under consideration a body, endued with one or oth of the properties mentioned, the idea he forms is n an abstract or general idea, but the idea of a parti ular body with its properties. But though a part ar the whole, a subject and its attributes, an effect ar its cause, are so intimately connected, as that an ide cannot be formed of the one independent of ti other ; yet we can reason upon the one abftractin from the other.
This is done by words fignifying the things which the reasoning is confined ; and such wore are denominated ahfiract terms. The meaning as use of an abstract term is well understood, thoug of itself, unless other particulars be taken in, it rail no image nor idea in the mind. In language it serve
excellent purposes ; by it different figures, different colours, can be compared, without the trouble of conceiving them as belonging to any particular subject; and they contribute with words fignificant to raise images or ideas in the mind.
42. The power of abstraction is bestowed on man, for the purpose folely of reasoning. It tends greatly to the facility as well as clearness of any process of reasoning, that, laying aside every other circumstance, we can confine our attention to the single property we desire to investigate.
43. Abstract terms may be separated into three different kinds, all equally subfervient to the reason. ing faculty. Individuals appear to have no end ; and did we not possess the faculty of distributing them into claffes, the mind would be lost in an endless maze, and no progress be made in knowledge. It is by the faculty of abstraction that we distribute beings into genera and species : finding a number of individuals connected by certain qualities common to all, we give a name to these individuals considered as thus connected, which name, by gathcring them together into one class, ferves to express the whole of these individuals as distinct from others. Thus the word animal serves to denote every being that can move voluntarily; and the words main, horse, lion, &c. answer kmilar purposes. This is the first and most common fort of abstraction ; and it is of the most extensive -use, by enabling us to comprehend in our reasoning whole kinds and forts, instead of individuals without end. The next fort of abftract terms comprehends a number of individual objects, considered as connected by fome occasional relation. A great number of persons collected in one place, without any other relation but merely that of contiguity, are denominated e crowd: in forming this term, we abstract from sex, from age, from condition, from dress, &c. A numt
ber of perfons connected by the same laws and by the fame government, are termed a nation : and a number of men under the fame military command, are termed an army. A third sort of abstraction is, where a single property or part, which may be common to many individuals, is selected to be the subject of our contemplation ; for example, whiteness, heat, beauty, length, roundness, head, arm.
44. Abstract terms are a happy invention : it is by their means chiefly, that the particulars which make the subject of our reasoning, are brought into close union, and separated from all others however naturally connected. Without the aid of such terms, the mind could never be kept steady to its proper subject, but be perpetually in hazard of assuming foreign circumstances, or negle&ing what are essential. We can, without the aid of language, compare real obje&s by intuition, when these objects are present; and when abfent, we can compare them in idea. But when we advance farther, and attempt to make inferences and draw conclusions, we always employ abstract terms, even in thinking ; it would be as difficult to reason without them, as to perform operations in algebra without signs ; for there is scarce any reasoning without some degree of abstraction, and we cannot easily abstract without using abstract terms. Hence it follows, that without language man would scarce be a rational being.
45. The same thing, in different respects, has different names. With respect to certain qualities, it is termed a substance ; with respect to other qualities, a body; and with respect to qualities of all sorts, a subject. It is termed a passive subject with respect to an action exerted upon it; an object with respect to a percipient; a cause with respect to the effect it produces; and an effect with respect to its cause.
[The volumes are denoted by numeral letters, the pages by figures.]
BSTRACTION) power of ii. 413. Its use ii. 414.
not be compared but by being personitied ii. 148. Pertonified ii.
al influence i. i 22.
279, 280. We are iinpelled to action by desire i. 43. Some ac-
conscious of it ii. 396.
to pronunciation betwixt the French and English actorsi. 362. note.
Affection for what belongs to us i. 64. Social attections more re-
influenced by affection i. 134. Affection defined i. 320. il. 408.
ble nor dilagreeable. See object.
ii. 231. In an historical poem ii. 310.
ed by a wrong arrangement ii. 44.
Amphybrachys ii. 142.
taneoully i. 98. Decays suddenly i. 101. Sometimes exerted
i. 129. Not infectious i. 146. Has no dignity in it i. 282.
not as they are in reality ii, 259.
arife without an object i. 57. Appetite for fame or esteem i. 164.
owing i. 244.
tafte for neatness and regularity ii. 380.
fible in an increasing series ii. 13. Arrangement of members in a
ii. 65, 66.
degree of attention ii. 410. Attention not always voluntary ii. 411,