gence, assist a brother or
a benefactor), he must consider these separate relations, with all the
circumstances and situations of the persons, in order to determine the
superior duty and obligation; and in order to determine the proportion
of lines in any triangle, it is necessary to examine the nature of that
figure, and the relation which its several parts bear to each other. But
notwithstanding this appearing similarity in the two cases, there is,
at bottom, an extreme difference between them. A speculative reasoner
concerning triangles or circles considers the several known and given
relations of the parts of these figures; and thence infers some unknown
relation, which is dependent on the former. But in moral deliberations
we must be acquainted beforehand with all the objects, and all their
relations to each other; and from a comparison of the whole, fix our
choice or approbation. No new fact to be ascertained; no new relation to
be discovered. All the circumstances of the case are supposed to be laid
before us, ere we can fix any sentence of blame or approbation. If any
material circumstance be yet unknown or doubtful, we must first employ
our inquiry or intellectual faculties to assure us of it; and must
suspend for a time all moral decision or sentiment. While we are
ignorant whether a man were aggressor or not, how can we determine
whether the person who killed him be criminal or innocent? But after
every circumstance, every relation is known, the understanding has no
further room to operate, nor any object on which it could employ itself.
The approbation or blame which then ensues, cannot be the work of the
judgement, but of the heart; and is not a speculative proposition or
affirmation, but an active feeling or sentiment. In the disquisitions of
the understanding, from known circumstances and relations, we infer some
new and unknown. In moral decisions, all the circumstances and relations
must be previously known; and the mind, from the contemplation of the
whole, feels some new impression of affection or disgust, esteem or
contempt, approbation or blame.

Hence the great difference between a mistake of FACT and one of RIGHT;
and hence the reason why the one is commonly criminal and not the other.
When Oedipus killed Laius, he was ignorant of the relation, and from
circumstances, innocent and involuntary, formed erroneous opinions
concerning the action which he committed. But when Nero killed
Agrippina, all t