Quality
Hegel (Logic of Being, first principal category)
Quality is the first principal category of the Logic of Being and of the entire logical system. It designates the immediate determinacy that is identical with being: the "What?" of a thing. Something does not have a quality but rather is its quality --- a rose is red, it does not "have" redness. If something loses its quality, it ceases to be what it is. Quality develops from pure being (absolutely indeterminate quality) through nothing and becoming to determinate being [Dasein] (determinate being as such), from there to "something and other" (mutual determination), through limit and barrier (finitude) to true infinity (return to itself in the other), and finally to being-for-itself (the highest quality, absolute negation). At the end of being-for-itself it becomes apparent that the many qualitatively identical "ones" differ only quantitatively. With this, quality passes over into quantity. Quality is determinacy as such, but still in immediate unity with being.
Origin
The term "quality" (Latin "qualitas") translates the Greek "poiótes" (constitution, characteristic) as used by Aristotle. There, quality is one of the ten categories (alongside quantity, relation, and so on). Scholastic philosophy distinguished between primary qualities (belonging to the thing itself: extension, solidity) and secondary qualities (dependent on the subject: color, taste) --- a distinction later taken up by Locke and the empiricists. Kant treats quality as a category of reality, negation, and limitation, but statically. Hegel makes quality dynamic: it develops within itself (being, determinate being, being-for-itself) and necessarily passes over into quantity. Quality is not a property of a substrate but the thing itself in its determinate determinacy. The qualitative leap (when the limits of measure are crossed) is Hegel's contribution to dialectic.
In Hegel
Enz. §86--98; Science of Logic, vol. 1, Doctrine of Being, Quality
Cross-references
Quantity · Measure · Being · Existence (Dasein) · Determinacy · Being-for-itself · Doctrine of Being · Boundary · Unendlichkeit · Umschlag [Turning Point / Qualitative Leap]