(Greek poistes Plato, Aristotle poion; Latin qualitas, quale.)
Quality is used, first, in an extended sense, as whatever can be attributed to the subject of discourse; and second, in its exact signification, as that category which is distinguished from the nine others enumerated by Aristotle. In the present article the word is treated in its stricter sense. The eighth chapter of the "Categories" treats of quality, as distinct from substance and the other predicaments. It is described, however, in the opening words of the sixth chapter of the same book as that on account of which we say that anything is such or such poioteta de lego, kath en poioi tines [einai] legontai. It is thus the accidental form which determines the subject to a special mode of being. It is the reply to the question Qualis sit res?, as St. Thomas Aquinas remarks; and is the correlative to Talis (as Quantus to Tantus), as is pointed out by James Mill in his "Analysis". As the notion is a simple one, it is not possible strictly to define it; for, to do this, it would be necessary to split it up into genus and differentia an impossibility where the simplest concepts are concerned. It is itself not a real genus, since many particular things, not generically identical can be subjects of the same predicate, analogically employed. Quality is the category according to which objects are said to be like or unlike; and, in view of the tendency introduced into modern science by the mechanist theories of Descartes, and fostered by the postulate of the transformation of energy, it is of importance that the qualitative should be distinguished from the quantitative differences of objects (cf. QUANTITY). Aristotle's classification of the heads of discourse in the "Categories" is a logical one, in which the attributes are considered as possible predicates of a subject. But they are further understood metaphysically; and, in this sense, quality is one or other of the four modes in which substance is determined to being talis or talis, i.e. such or such. Considered thus, it is an accidental determination (cf. FORM).
The four divisions of quality are:
ARISTOTLE, Opera omnia (Paris, 1619); GROTE, Aristotle (London, 1872); LORENZELLI, Philosophi Theoretic Institutiones (Rome, 1896); MERCIER, Ontologie (Louvain, 1902); NYS, Cosmologie (Louvain, 1906); ST. THOMAS AQUINAS, Opera (Parma, 1852), (cf. especially, De natura generis, De natura accidentis).
APA citation. (1911). Quality. In The Catholic Encyclopedia. New York: Robert Appleton Company. http://www.newadvent.org/cathen/12589c.htm
MLA citation. "Quality." The Catholic Encyclopedia. Vol. 12. New York: Robert Appleton Company, 1911. <http://www.newadvent.org/cathen/12589c.htm>.
Transcription. This article was transcribed for New Advent by Douglas J. Potter. Dedicated to the Sacred Heart of Jesus Christ.
Ecclesiastical approbation. Nihil Obstat. June 1, 1911. Remy Lafort, S.T.D., Censor. Imprimatur. +John Cardinal Farley, Archbishop of New York.
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