Abstract, adj

  1. Being apart from or considered apart from the actual subject of being.
  2. Expressing an essence, property, quality, or other attribute apart from a concrete subject or thing; e.g., sweetness, humanity, patience.

Abbreviation—abs., abstr.

Antonym—Concrete.  It is not properly contrasted with realistic.  In scholasticism it is seldom synonymous with universal.

Uses—abstract idea, noun, term, etc.  In the abstract, absolutely; in a condition of mental separation from other concrete relationships and circumstances.

Abstracted, part. As adj.  removed or separated from something, usually by some mental act.

Abstraction, n.

  1. in general, a mental act apprehending some note or formal object of a thing in which the mind attends to this note and does not attend to other notes naturally present in the same concrete object of perception.  Abstraction thus has first a negative aspect of detaching or leaving out something as well as a second positive aspect of concentration on some object considered apart from other aspects actually present in the particular real thing.
  2. Abstraction by the senses in which a sense attends to one sensible property and not to others in the sensible object; as the eye attends only to the color and not to the temperature or taste of an apple.
  3. Abstraction by the imagination in which the imagination considers a material object of some features of it, but does not attend to the presence of absence of that object.
  4. Abstraction by the intellect in which the intellect considers the nature or a form apprehended in a material object or in the image (phantasm).

Compare: analysis; distinction; intention; matter; prescission; separation; universal.  This intellectual abstraction, to which reference is usually made in philosophical writing, can be of several kinds.  

  1. Abstraction of first intention, the mental act which results in a direct universal concept or which apprehends an essence which is common to many things.
  2. Abstraction of second intention, an act of judgment following the abstraction of first intention and which results in a reflex universal (or transcendental) concept wherein the mind recognizes the universal nature represented as being common to many and predicable of many
  3. Abstractive abstraction, the mental act forming an abstract concept which represents the object attended to as completely detached from its concrete object; e.g., sweetness, roundness, courage are thus abstracted. 
  4. First mode (first degree) of abstraction, the abstraction, proper to the philosophy or nature, in which the mind disregards individual (signate) matter, but retains sensible matter while attaining to the universal nature of the material reality so known.  Examples are the abstractions which form our first concepts of water as such, or color as such.
  5. Formal abstraction, an intellectual separation of a form from sensible matter, without attending to the matter or other forms present at the same time in the object; e.g., abstraction of mathematical objects from physical objects.
  6. Second mode (second degree) of abstraction, the abstraction, proper to mathematics, in which the mind disregards both signate and sensible matter, but retains intelligible matter while attaining to the concept of abstract quantity.  Examples are the abstractions which form our concepts of circle, plane, etc.
  7. Third mode (third degree) of abstraction, the abstraction, more properly called a separation or judgment, peculiar to metaphysics, in which the mind disregards all matter and grasps its object without any necessary relation to matter.  Examples are the mind’s knowledge of being, existence, substance, unity, etc.
  8. Total abstraction, the intellectual representation of the universal or absolute nature taken from the particulars in which the nature exists; the abstraction of the whole nature or essence from all accidental elements in the concrete object.

References: De Anima, I, c. 1, near end.  S.T. I, 40, a. 3; 85, a. 1 ad 1, 2.  De Veritate, q. 2, a. 6.  De Trin., q. 5, a. 3.  This last text is that principally followed in the foregoing expositions, some of which are differently explained by other scholastic writers.