Quantity is a property that can exist as a magnitude or multitude. Quantities can be compared in terms of "more", "less" or "equal", or by assigning a numerical value in terms of a unit of measurement. Quantity is among the basic classes of things along with quality, substance, change, and relation. Being a fundamental term, quantity is used to refer to any type of quantitative properties or attributes of things. Some quantities are such by their inner nature (as number), while others are functioning as states (properties, dimensions, attributes) of things such as heavy and light, long and short, broad and narrow, small and great, or much and little. A small quantity is sometimes referred to as a quantulum.
Two basic divisions of quantity, magnitude and multitude, imply the principal distinction between continuity (continuum) and discontinuity.
Under the names of multitude come what is discontinuous and discrete and divisible into indivisibles, all cases of collective nouns: army, fleet, flock, government, company, party, people, chorus, crowd, mess, and number. Under the names of magnitude come what is continuous and unified and divisible into divisibles, all cases of non-collective nouns: the universe, matter, mass, energy, liquid, material, animal, plant, tree.
Along with analyzing its nature and classification, the issues of quantity involve such closely related topics as the relation of magnitudes and multitudes, dimensionality, equality, proportion, the measurements of quantities, the units of measurements, number and numbering systems, the types of numbers and their relations to each other as numerical ratios.
Thus quantity is a property that exists in a range of magnitudes or multitudes. Mass, time, distance, heat, and angular separation are among the familiar examples of quantitative properties. Two magnitudes of a continuous quantity stand in relation to one another as a ratio, which is a real number.
Famous quotes containing the word quantity:
“The Great Society is a place where every child can find knowledge to enrich his mind and to enlarge his talents.... It is a place where the city of man serves not only the needs of the body and the demands of commerce but the desire for beauty and the hunger for community.... It is a place where men are more concerned with the quality of their goals than the quantity of their goods.”
—Lyndon Baines Johnson (19081973)
“Something is infinite if, taking it quantity by quantity, we can always take something outside.”
—Aristotle (384322 B.C.)
“A bureaucracy is sure to think that its duty is to augment official power, official business, or official members, rather than to leave free the energies of mankind; it overdoes the quantity of government, as well as impairs its quality. The truth is, that a skilled bureaucracy ... is, though it boasts of an appearance of science, quite inconsistent with the true principles of the art of business.”
—Walter Bagehot (18261877)