3. Hume. Hutcheson's argument against rationalist
ethics gave David Hume the initial impetus to develop
the implications of empiricism not only in ethics but
over the whole range of philosophy. Hume's contri-
bution to the theory of moral sense was made in Book
III of A Treatise of Human Nature (London, 1740) and
in An Enquiry concerning the Principles of Morals
(London, 1751). In both works Hume uses the word
“sentiment” more commonly than “sense,” but the
meaning is the same. In the Treatise the titles of the
first two sections of Book III state that moral distinc-
tions are not derived from reason but are derived from
a moral sense. Here the expression “moral sense” is
retained from Hutcheson, and the issue raised in these
sections is probably the point from which the whole
of Hume's philosophy originated.
Hume continues but does not add significantly to
the analogy between ethical and aesthetic judgment
that had been drawn by Shaftesbury and Hutcheson.
The importance of Hume's contribution to the moral
sense theory lies in three things. First, he works out
an extraordinarily powerful development of Hutche-
son's criticism of rationalist ethics. Secondly, where
Hutcheson had taken the moral sense or sentiment of
approval to be simply an original datum of human
nature, Hume explains it as being the result of sympa-
thy and thereby makes it seem less mysterious and more
clearly connected with a utilitarian approach to ethics.
Thirdly, while Hutcheson had supposed that the object
of moral approval is always a species or consequence
of benevolence, Hume distinguishes between benevo-
lence and justice as “natural” and “artificial” virtue
respectively, and recognizes that the approval of justice
by the moral sense cannot be so simple and
straightforward as the approval of benevolence.
Hume's view of the respective functions of reason
and feeling in moral judgment is essentially that of
Hutcheson: reason shows us means, sentiment selects
ends. But Hume supports the position with a battery
of arguments which together constitute as damaging
an assault as can be found anywhere in the history of
philosophy. In the Treatise they are all the more mem-
orable for being stated with trenchant epigram and
wit. “Reason is and ought only to be the slave of the
passions”; “an active principle can never be founded
on an inactive”; if immorality were telling a lie in
action, as one rationalist contends, then immorality
could be avoided merely by concealment, e.g., by
closing the shutters when seducing a neighbor's wife;
a “small attention” to the difficulty of deducing ought
from is “would subvert all the vulgar systems of moral-
ity.” Hume's chief argument is that reason cannot move
to action, as passion can, and since moral judgment
is a motive to action it cannot be an expression of
reason. This argument is supplemented by taking in
turn each of the functions that can be attributed to
reason and showing that none of them can suffice for
moral judgment. As in aesthetics, when reason has done
all that it can do to ascertain the facts, sentiment or
taste must supervene to produce an idea of value,
which is nothing objective but the expression of a
spectator's reaction to the objective facts.
The reaction of the moral sense or sentiment, how-
ever, need not be left unexplained as an ultimate in-
stinct of human nature. It is the effect of sympathy
with the feelings of those who are affected by an action.
Benevolence aims at giving happiness or removing
pain, and usually it succeeds in its aim. A spectator
of a benevolent action feels a sympathetic pleasure
with the pleasure of the person benefited, and this gives
rise to the particular kind of pleasant feeling that
constitutes moral approval. Similarly disapproval is a
particular kind of unpleasant feeling arising from sym-
pathetic pain with the pain of those who are harmed
by actions termed vicious or morally bad. Hutcheson
had connected the moral sense with the sense of honor
by saying that the latter is a form of pleasant feeling
which results from the observation that we are ap-
proved by the moral sense of others, but he had left
the moral sense and the public sense (sympathy) as two
independent and ultimate features of human nature.
Hume connects them in the sort of way in which
Hutcheson had connected the moral sense with the
sense of honor, and in consequence there is now a chain
of causation for all three; sympathy causes approval,
and the knowledge that one is approved causes pride
(Hutcheson's sense of honor). A further advantage of
Hume's supplement to the theory of moral sense is that
the connection between approval and utility becomes
more evident. Approval is not simply a quasi-aesthetic
reaction to the beauty of benevolence; it is the result
of sympathetic pleasure with the effect of benevolence,
namely the happiness of one's neighbors, and so it can
be generalized into pleasure at the happiness of man-
kind. In Hume's view, approval is directed both at the
immediately agreeable and at the useful.
So much for the approval of “natural” virtue,
benevolence, and its usual consequences. The approval
of justice is more puzzling, for the stern countenance
of justice lacks the beauty of benevolence, and yet the
rules of justice are approved even when, in particular
instances, they oppose utility. Hume treats justice as
“artificial” virtue; approval of it does not depend on
human nature alone, as does the approval of benevo-
lence. The rules of justice are a man-made device,
necessary because a feature of human nature, selfishness
and limited generosity, is combined with a feature of
the human situation, the scarcity of goods in relation
to men's wants. The rules of justice give men protection
for their share of scarce goods. Self-interest leads each
man to support the rules, and sympathy with the gen-
eral interest adds moral approval. The feeling of
approval, which was originally directed towards the
utility of the rules, becomes attached by association
to the rules themselves and remains even in instances
where the application of the rules is not useful. Thus
a sense of duty can lose contact with sympathy, the
original natural basis of approval, and can become an
inflexible approval of rules as such.
In this way Hume takes account of a feature of
morality that had impressed rationalist or natural law
theorists. He also allows that moral and aesthetic judg-
ments are made from a general point of view. They
do not express actual feelings, which vary with varying
circumstances. As in his theory of knowledge, Hume
attributes to the imagination the generalizing activity
that others would attribute to reason. In the end,
therefore, his theory shares certain insights of the
rationalists, though undoubtedly explaining them in a
different spirit, within a different framework of ideas.
