Founded in our
nature and revealed to us by our
reason, the
moral law is known to us in the measure that
reason brings a
knowledge of it home to our understanding. The question arises: How far can
man be
ignorant of the natural law…the supreme and primary principles are necessarily known to every one having the actual use of
reason. These principles are really reducible to the primary principle which is expressed by St. Thomas in the form: “Do good and avoid
evil”. Wherever we find
man we find him with a
moral code, which is founded on the first principle that good is to be done and
evil avoided. When we pass from the universal to more particular conclusions, the case is different. Some follow immediately from the primary, and are so self-evident that they are reached without any complex course of reasoning. Such are, for example: “Do not commit
adultery”; “Honour your
parents”. No
person whose
reason and
moral nature is ever so little developed can remain in
ignorance of such
precepts except through his own fault.Another class of conclusions comprises those which are reached only by a more or less complex course of reasoning. These may remain unknown to, or be misinterpreted even by
persons whose
intellectual development is considerable. To reach these more remote
precepts, many facts and
minor conclusions must be correctly appreciated, and, in estimating their value, a
person may easily
err, and consequently, without
moral fault, come to a
false conclusion…
newadvent.org/cathen/09076a.htm