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and cannot exist independent of each other: the fame of length, breadth, and thickness: and yet we can mentally confine our observations to one of these, neglecting or abftracting from the rest. Here abstraction takes place where there cannot be a real separation. sobi Lenids'

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38. This power of abstraction is of great utility. A carpenter confiders a logo of wood, with regard to hardness, firmness, colour, and texture: a philosopher, neglectting these properties, makes the log undergo a chymical analysis; and examines sits taste, its smell, and its component principles: the geometrician confines his reasoning to the figure, the length, breadth, and thickness. In general, every artist, abstracting from all other properties, confines his observations to those which have a more immediate connection with his profeffionmodt 53 39. Hence elearly appears the meaning of an abstract term, and abstract idea. If in viewing an object, we can abstract from fome of its parts or properties, and attach Courselves to others; there must be the same facility, when we recall this object to the mind mind in idea. This leads directly to the definition of an abstract idea, viz. " A partial view of a complex object, limited to one or more of the component parts or properties, laying afide or abstracting "from others." A word that denotes an abstract idea, is called an abstract term....... 39 40. The power of abstraction is bestowed Tupon man, for the purposes solely of reafoning. It tends greatly to the facility as well as clearness of any process of reasoning, that, withdrawing from every other circumstance, we can confine our attention to the single property we defire to investigate. -0041 Abstract ideas, may, I think, be distinguished into three different kinds, all equally subservient to the reasoning faculty. Individuals appear to have no end; and did we not possess the faculty of distributing them into classes, the mind would be loft in an endless variety, 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 3 E 2

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individuals confidered as thus connected; which name, by gathering them together into one class, ferves in a curt manner to express the whole of these individuals as distinct from others. Thus the word animal serves to denote every being which hath self-motion; and the words man, horse, lion, &c. answer similar 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 rea foning whole kinds and forts, instead of individuals without end. The next fort of abstract ideas and terms comprehends a number of individual objects confidered as connected by fome occasional relation. A great number of persons collected together in one place, without any other relation but merely that of contiguity, are denominated a crowd: in forming this term, we abstract from fex, from age, from condition, from dress, &c. A number of perfons connected by being fubjected to the same laws and to the fame government, are termed a nation; and a number of men subjected to the fame military tary command, are termed an army. A third fort of abstraction is, where a fingle property or part, which may be common to many individuals, is selected to be the fubject of our contemplation; for example, whiteness, heat, beauty, length, roundness, head, arm.

42. Abstract terms are a happy invention: it is by their means chiefly, that the particulars which we make the fubject of our reafoning, 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 fubject, but would perpetually be in hazard of assuming foreign circumstances or neglecting what are effential. In a word, a general term denotes in a curt manner certain objects occafionally combined. We can, without the aid of language, compare real objects by intuition, when these objects are present; and, when abfent, we" can compare them by means of the ideas we have of them: but when we advance farther, and attempt to make inferences, and draw conclufions, we always employ abstract

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abstract terms, even in thinking. 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 abftraction; and we cannot abstract to purpose without making use of general terms. Hence it follows, that without language man would scarce be a rational being.

43. 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 forts, a fubject: it is termed a paffive fubject with respect to an action exerted upon it; an object with respect to a percipient; a caufe with respect to the effect it produces; and an effect with refpect to its caufe.

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