nin, 'is one of the most important of all the
determinants of value, for labour is the chief element in cost of
production, and cost of production is one of the chief elements in
determining the level at which it is useful to buy or sell. But labour
is not the only determinant of value; there is, _e.g._, the price of
the raw materials, a price that is not wholly determined by the labour
of producing those materials.'[4]

[Footnote 1: _Political Economy_, s. 48.]

[Footnote 2: _Politische Oekonomie vom Standpuncte der geschichtlichen
Methode_, p. 116.]

[Footnote 3: _Op. cit._, p. 112.]

[Footnote 4: _Ethics_, vol. ii. p. 181.]

The just price, then, in the absence of a legal fixing, was held to
be the price that was in accordance with the _communis estimatio_.
Of course, this did not mean that a plebiscite had to be taken before
every sale, but that any price that was in accordance with the general
course of dealing at the time and place of the sale was considered
substantially fair. 'A thing is worth what it can generally be sold
for--at the time of the contract; this means what it can be sold for
generally either on that day or the preceding or following day. One
must look to the price at which similar things are generally sold
in the open market.'[1] 'We must state precisely,' says the Abbe
Desbuquois, 'the character of this common estimation; it did not mean
the universal suffrage; although it expresses the universal interest,
it proceeds in practice from the evaluation of competent men, taken
in the social environment where the exchange value operates. If one
supposes a sovereign tribunal of arbitration where all the rights
of all the weak and all the strong economic factors are taken into
account, the just price appears as the sentence or decision of this
court.'[2] 'For the scholastics, the common estimation meant an
ethical judgment of at least the most influential members of
the community, anticipating the markets and fixing the rate of
exchange.'[3]

[Footnote 1: Caepolla, _De Cont. Sim._, 72.]

[Footnote 2: _Op. cit._, pp. 169-70.]

[Footnote 3: Fr. Kelleher in the _Irish Theological Quarterly_, vol.
xi. p. 133.]

It is quite incorrect to say, as has been sometimes said, that the
mediaeval just price was in no way different from the competition
price of to-day which is arrived at by the higgling of the market.
Dr. Cunningham is very explicit and clear on this point. 'Common
estimation is thus the