Editing Marginalism (section)

=== Marginality ===
For issues of marginality, constraints are conceptualized as a ''border'' or ''margin''.<ref>[[Philip Wicksteed|Wicksteed, Philip Henry]]; ''The Common Sense of Political Economy'' (1910), Bk I Ch 2 and elsewhere.</ref> The location of the margin for any individual corresponds to his or her ''endowment'', broadly conceived to include opportunities.  This endowment is determined by many things including physical laws (which constrain how forms of energy and matter may be transformed), accidents of nature (which determine the presence of natural resources), and the outcomes of past decisions made both by others and by the individual.

A value that holds true given particular constraints is a [[marginal value|''marginal'' value]]. A change that would be affected as or by a specific loosening or tightening of those constraints is a ''marginal'' change.

Neoclassical economics usually assumes that marginal changes are [[infinitesimal]]s or [[Limit (mathematics)|limits]]. Although this assumption makes the analysis less robust, it increases tractability. One is therefore often told that "marginal" is synonymous with "very small", though in more general analysis this may not be operationally true and would not in any case be literally true. Frequently, economic analysis concerns the marginal values associated with a change of one unit of a resource, because decisions are often made in terms of units; marginalism seeks to explain unit prices in terms of such marginal values.