Quantity

Quantity is the second main category of the logic of being (after quality, before measure). It is being to which determinateness has become indifferent. Whereas with quality the "what?" of a thing stands in the foreground (a rose is red, not blue), quantity asks "how much?" (how large, how heavy, how many?). The decisive point is this: the quantitative determination can change without the thing losing its identity — a table remains a table whether it is 1 meter or 2 meters long. This "indifference" of quantity is its defining property — and at the same time what the doctrine of quantity actually derives: **mathematizability**. That one can disregard the constitution of a thing and consider only its magnitude is not a starting point but a result of the logic of quality. The flip side of this is the interpretive openness of mathematics: because quantity disregards the what, the same equation can describe a pendulum and an electrical circuit. This is the reason for the reach of mathematical natural science, and at the same time for its limit — what it grasps, it grasps by disregarding the what. Pure quantity has a double structure: it is at once continuous (flowing, infinitely divisible) and discrete (composed of countable units). This tension shows up in the mathematical problem of the continuum. As determinate quantity, it becomes a quantum (a determinate magnitude), which differentiates into extensive magnitude (divisible, addable, like length, mass) and intensive magnitude (indivisible, a degree, like temperature, density). In the quantitative ratio, quantity relates to itself (in the ratio of powers), whereby it returns to quality and passes over into measure.