Thus monopoly is limited by competition, and no owner, whether of labour, land or capital, can, theoretically speaking,obtain a larger share of produ… - William Stanley Jevons

By a commodity we shall understand any object, substance, action or service, which can afford pleasure or ward off pain.

Nature is to us like an infinite ballot-box, the contents of which are being continually drawn, ball after ball, and exhibited to us. Science is but the careful observation of the succession in which balls of various character present themselves; we register the combinations, notice those which seem to be excluded from occurrence, and from the proportional frequency of those which usually appear we infer the probable character of future drawings.

The difficulties of economics are mainly the difficulties of conceiving clearly and fully the conditions of utility.