Such a system Dr. Whewell wishes to construct in the field of ethics.
His aim is to give us a view of morality in which moral propositions
are "deduced from axioms, by successive steps of reasoning, so far as
to form a connected system of moral truth." Such a "sure and connected
knowledge of the duties of man" would, he thinks, be of the greatest
importance.

In accordance with this purpose, Dr. Whewell assumes that humanity,
justice, truth, purity, order, earnestness, and moral purpose are
fundamental principles of human action; and he thinks that all who
admit as much as this will be able to go on with him in his development
of a system of moral rules to govern the life of man.

It would hardly be worth while for me to speak at length of a way of
treating ethics so little likely to be urged upon the attention of the
reader who busies himself with the books which are appearing in our own
day, were it not that we have here an admirable illustration of the
attempt to teach ethics as though it were such a science as geometry.
The shortcomings of the method become very evident to one who reads the
work attentively.

Thus, we are forced to ask ourselves, have we really a collection of
ultimate moral principles which are analogous to the axioms of
geometry? For example, to take but a single instance, Dr. Whewell
formulates the Principle of Truth as follows: "We must conform to the
universal understanding among men which the use of language
implies";[2] and he remarks later; "The rules: _Lie not_, Perform your
promise, are of universal validity; and the conceptions of _lie_ and of
_promise_ are so simple and distinct that, in general, the rules may be
directly and easily applied." [3]

Now, we are struck by the fact that this affirmation of the universal
validity of the principle of truth is made in a chapter on "Cases of
Conscience," in a chapter concerned with what seem to be conflicts
between duties; and this chapter is followed by one which treats of
"Cases of Necessity," _i.e._ cases in which a man is to be regarded as
justified in violating common rules when there seems to be urgent
reason for so doing. We are told that the moralist cannot say: Lie
not, except in great emergencies; but must say: Lie not at all. But we
are also told that he must grant that there are cases of necessity in
which transgressions of moral rules are excusable; and this looks very
much as if he said: Go on and do the thing while I clo