exponent of the natural or normal or just price
according to either the mediaeval or modern view; but, whereas we rely
on the higgling of the market as the means of bringing out what is the
common estimate of any object, mediaeval economists believed that it
was possible to bring common estimation into operation beforehand,
and by the consultation of experts to calculate out what was the just
price. If common estimation was thus organised, either by the town
authorities or guilds or parliament, it was possible to determine
beforehand what the price should be and to lay down a rule to this
effect; in modern times we can only look back on the competition
prices and say by reflection what the common estimation has been.'[1]
'The common estimation of which the Canonists spoke,' says Dr. Ryan,
'was conscious social judgment that fixed price beforehand, and was
expressed chiefly in custom, while the social estimate of to-day is
in reality an unconscious resultant of the higgling of the market, and
finds its expression only in market price.'[2] The phrase 'res tanti
valet quanti vendi potest,' which is so often used to prove that
the mediaeval doctors permitted full competitive prices in the modern
sense, must be understood to mean that a thing could be sold at any
figure which was within the limits of the minimum and maximum just
price.[3]

[Footnote 1: _Growth of English Industry and Commerce_, vol. i. p.
353.]

[Footnote 2: _Living Wage_, p. 28.]

[Footnote 3: Lessius, _De Justitia et Jure_, xxi. 19.]

The last sentence suggests that the just price was not a fixed and
unalterable standard, but was somewhat wide and elastic. On this all
writers are agreed. 'The just price of things,' says Aquinas, 'is not
fixed with mathematical precision, but depends on a kind of estimate,
so that a slight addition or subtraction would not seem to destroy
the equality of justice,'[1] Caepolla repeats this dictum, with the
reservation that, when the just price is fixed by law, it must be
rigorously observed.[2] 'Note,' says Gerson, 'that the equality of
commutative justice is not exact or unchangeable, but has a good deal
of latitude, within the bounds of which a greater or less price may
be given without justice being infringed;'[3] and Biel insists on the
same latitude, from which he draws the conclusion that the just price
is constantly varying from day to day and from place to place.[4]
Generally it was said that there was a maximu