I have
not known learning," [*Cf. Obj. 1] says: "The greedy tradesman
blasphemes over his losses; he lies and perjures himself over the
price of his wares. But these are vices of the man, not of the craft,
which can be exercised without these vices." Therefore trading is not
in itself unlawful.

_I answer that,_ A tradesman is one whose business consists in the
exchange of things. According to the Philosopher (Polit. i, 3),
exchange of things is twofold; one, natural as it were, and
necessary, whereby one commodity is exchanged for another, or money
taken in exchange for a commodity, in order to satisfy the needs of
life. Such like trading, properly speaking, does not belong to
tradesmen, but rather to housekeepers or civil servants who have to
provide the household or the state with the necessaries of life. The
other kind of exchange is either that of money for money, or of any
commodity for money, not on account of the necessities of life, but
for profit, and this kind of exchange, properly speaking, regards
tradesmen, according to the Philosopher (Polit. i, 3). The former
kind of exchange is commendable because it supplies a natural need:
but the latter is justly deserving of blame, because, considered in
itself, it satisfies the greed for gain, which knows no limit and
tends to infinity. Hence trading, considered in itself, has a certain
debasement attaching thereto, in so far as, by its very nature, it
does not imply a virtuous or necessary end. Nevertheless gain which
is the end of trading, though not implying, by its nature, anything
virtuous or necessary, does not, in itself, connote anything sinful
or contrary to virtue: wherefore nothing prevents gain from being
directed to some necessary or even virtuous end, and thus trading
becomes lawful. Thus, for instance, a man may intend the moderate
gain which he seeks to acquire by trading for the upkeep of his
household, or for the assistance of the needy: or again, a man may
take to trade for some public advantage, for instance, lest his
country lack the necessaries of life, and seek gain, not as an end,
but as payment for his labor.

Reply Obj. 1: The saying of Chrysostom refers to the trading which
seeks gain as a last end. This is especially the case where a man
sells something at a higher price without its undergoing any change.
For if he sells at a higher price something that has changed for the
better, he would seem to receive the reward of his labor.
Nev