An ABSTRACT Idea, is some simple Idea, detach'd and separated from any particular Subject, or Complex Idea ; for the sake of viewing and considering it more distinctly, as it is in itself, its own Nature, &c. See IDEA, SIMPLE, COMPLEX, &c.
Thus, Magnitude and Humanity are Abstracts when consider'd in themselves, and without being attached to any particular Body, or Person ; tho they cannot have any real Subsistence without such Subjects, nor the Subjects without them.
Thus, also, Whiteness is an Abstract, or abstract Term ; inasmuch as it does not denote any one white Object, but that Colour or Idea in the general, wherever sound. See GENERAL.
From the Knowledge of Abstracts we arrive at that of Concretes, which is the opposite Term ; Concrete denoting a General or Abstract Idea's being attach'd to same particular Subject, or consider'd as combin'd with some other Ideas ; as, great House, white Wall. See CONCRETE.
The School Philosophers define an Abstract Term from the Simplicity of its Signification.— Abstracts, according to them, express only the Forms of Things, or Attributes of Things, distinct from the Subjects whereof they are Forms or Attributes : as, Justice, Crookedness, &c.— They distinguish 'em into divers Kinds ; Metaphysical, as Humanity ; Logical, as Whiteness ; and Physical, as Life, in respect of an Animal.
All our simple Ideas, says Mr. Locke, have abstract, as well as concrete Names 3 as, Whiteness, white ; Sweetness, sweet, &c.
The like also holds in our Idea of Modes, and Relations ; as, Justice, just ; Equality, equal ; &c.
But as to our Ideas of Substances, we have very few abstract Names at all— Those few that the Schools have forged, as Animalitas, Humanitas, &c. hold no Proportion with the infinite Number of Names of Substances ; and could never get admittance into common Use, or obtain the Licence of publick Approbation : which seems to intimate a Confession of Mankind, that they have no Ideas of the real Essences of Substances ; since they have not Names for such Ideas.
It was only the Doctrine of Substantial Forms, and the Confidence of mistaken Pretenders to a Knowledge they had not, which first coined, and then introduced Animalitas, Humanitas, and the like ; which yet went very little farther than their own Schools, and could never get to be current among understanding Men. See SUBSTANCE.
But the Reality and Exigence of all Abstract Ideas, and of any such Faculty in the Mind as Abstraction, has of late been controverted. See the Article ABSTRACTION.
In effect, is there were any such Things as Abstracts, Abstract Qualities, &c. we don't see how they could be destroy'd ; they must be permanent and immutable : For that which destroys the white warm Flame, cou'd not reach the Whiteness or the Warmth : That which destroys the figured, moving, solid Ball, could not hurt the Figure, Motion, Solidity, &c.— Abstract Ideas, in fine, seem to tend to Substantial Forms. See SUBSTANTIAL FORM.
ABSTRACT is also extended to divers other Things, in respect of their Purity, Simplicity, Subtility, &c. In this Sense, we say,
ABSTRACT MATHEMATICKS, are those Branches of Mathematical Learning, which consider Quantity and its Affections, simply, and absolutely. See QUANTITY, and MATHEMATICS.
Such are Arithmetic, Algebra, Geometry, Trigonometry, and Analyticks. See ARITHMETIC, ALGEBRA, GEOMETRY, &c.
They are thus denominated, in opposition to Mixt Mathematicks ; where the simple and abstracted Properties and Relations of Quantity deliver'd in the former, are applied to sensible Objects ; and by that means become intermix'd with Physical Considerations Such are Hydrostatics, Optics, Navigation, &c. where Water, Light, &c. are concern'd.
In the like Sense some Authors speak of Abstract Numbers ; meaning no more thereby than Numbers, or Assemblages of Unities, consider'd in themselves, and not applied to denote any Collections of particular sorts of Things. See NUMBER.
ABSTRACT is also used in Matters of Literature, for a compendious View, or Epitome of a larger Work. See EPITOME.
An Abstract is supposed to be a degree shorter, and more superficial than an Abridgment. See ABRIDGMENT.