SUMMARY OF DEFINITIONS 331

Coefficient, of probability. — The ratio of mathematical value to riskless
 value. Ch. XVI, § 6.
of risk. — The ratio of commercial value to riskless value; hence
the product of the coefficient of caution multiplied by the
coefficient of probability. Ch. XVI, § 6.
Commercial basis. — (See Basis, commercial.)
value of a chance. — (See Chance, commercial value of.)
Commodities. — Movable instruments not human beings. Ch.I, § 2.
Consumption. — (See Services, enjoyable objective.)
Couple. — A liability to a debtor and its counterpart asset to the
creditor. Or the service of one instrument acting on another
and the counterpart disservice of the second acted on by the
first. Ch. VI, § 1; Ch. IX, § 2.
Coupled services. — (See Couple, Interaction.)
Depreciation fund. — (See Fund, depreciation.)
Desirability of goods (wealth, property, or services). — The intensity
 of desire, for those goods, of a particular individual at a
particular time under particular circumstances. (Syn. Utility.)
Ch. IIT, § 2.
marginal — of a specified aggregate of goods. — Approximate
definition: The desirability of one unit more or less of that
‘aggregate, or the difference between the desirability of that
aggregate and another aggregate one unit larger or smaller.
Ch. 111, § 4.
Exact definition: The limit of the ratio of the increment
(or decrement) of desirability to the increment (or decrement)
of the aggregate when the last-named increment (or decrement)
approaches zero. (Syn. Marginal utility.) Appendix to Ch.
I, § 1.
progressive marginal —of a specified aggregate of goods. — The
desirability of one unit more of that aggregate. (Syn. Pro-_
 gressive marginal utility.) Appendix to Ch. 111, §1.
regressive marginal —of a specified aggregate of goods.— The desirability
 of one unit less of that aggregate. (Syn. Regressive
marginal utility.) Appendix to Ch. 111, § 1.
total—of an aggregate of goods.—The difference between the
desirability of goods which include and of those which exclude
that aggregate. (Syn. Total utility.) Ch. III, § 4.
Dimension. — The kind or species of any magnitude as indicated
by its measurement in terms of other magnitudes. Appendix
to Ch. I.
Discount curve. — A curve so constructed that, if one of its ordinates
represents any given sum, any later ordinate will represent the