Gregory Bateson quote: “Rather, for all objects and experiences there is a quantity that has an optimum value. Above that quantity, the variabl…”

“In economic surveys of households, many variables have the following characteristics: The variable has a lower, or upper, limit and takes on the limiting value for a substantial number of respondents. For the remaining respondents, the variable takes on a For the remaining respondents, the variable takes on a wide range of values above, or below, the limit.”

James Tobin (1918–2002) American economist

Tobin, James. " Estimation of relationships for limited dependent variables http://cowles.econ.yale.edu/P/cp/p01a/p0117.pdf." Econometrica: journal of the Econometric Society (1958): 24-36.
1950s-60s

“A function of a variable quantity is an analytic expression composed in any way whatsoever of the variable quantity and numbers or constant quantities.”

Leonhard Euler (1707–1783) Swiss mathematician

§4
Introduction to the Analysis of the Infinite (1748)

“When… we have a series of values of a quantity which continually diminish, and in such a way, that name any quantity we may, however small, all the values, after a certain value, are severally less than that quantity, then the symbol by which the values are denoted is said to diminish without limit. And if the series of values increase in succession, so that name any quantity we may, however great, all after a certain point will be greater, then the series is said to increase without limit. It is also frequently said, when a quantity diminishes without limit, that it has nothing, zero or 0, for its limit: and that when it increases without limit it has infinity or ∞ or 1⁄0 for its limit.”

Augustus De Morgan (1806–1871) British mathematician, philosopher and university teacher (1806-1871)

Introductory Chapter, pp.9-10
The Differential and Integral Calculus (1836)

“When… we have a series of values of a quantity which continually diminish, and in such a way, that name any quantity we may, however small, all the values, after a certain value, are severally less than that quantity, then the symbol by which the values are denoted is said to diminish without limit. And if the series of values increase in succession, so that name any quantity we may, however great, all after a certain point will be greater, then the series is said to increase without limit.”

Augustus De Morgan (1806–1871) British mathematician, philosopher and university teacher (1806-1871)

It is also frequently said, when a quantity diminishes without limit, that it has nothing, zero or 0, for its limit: and that when it increases without limit it has infinity or ∞ or 1&frasl;0 for its limit.
The Differential and Integral Calculus (1836)