act towards the end, as material
to formal, as stated above (I-II, Q. 18, AA. 6, 7).

Now it has been said above (Q. 109, A. 1, ad 3) that the virtue of
truth--and consequently the opposite vices--regards a manifestation
made by certain signs: and this manifestation or statement is an act
of reason comparing sign with the thing signified; because every
representation consists in comparison, which is the proper act of the
reason. Wherefore though dumb animals manifest something, yet they do
not intend to manifest anything: but they do something by natural
instinct, and a manifestation is the result. But when this
manifestation or statement is a moral act, it must needs be
voluntary, and dependent on the intention of the will. Now the proper
object of a manifestation or statement is the true or the false. And
the intention of a bad will may bear on two things: one of which is
that a falsehood may be told; while the other is the proper effect of
a false statement, namely, that someone may be deceived.

Accordingly if these three things concur, namely, falsehood of what
is said, the will to tell a falsehood, and finally the intention to
deceive, then there is falsehood--materially, since what is said is
false, formally, on account of the will to tell an untruth, and
effectively, on account of the will to impart a falsehood.

However, the essential notion of a lie is taken from formal
falsehood, from the fact namely, that a person intends to say what is
false; wherefore also the word _mendacium_ (lie) is derived from its
being in opposition to the _mind._ Consequently if one says what is
false, thinking it to be true, it is false materially, but not
formally, because the falseness is beside the intention of the
speaker so that it is not a perfect lie, since what is beside the
speaker's intention is accidental for which reason it cannot be a
specific difference. If, on the other hand, one utters falsehood
formally, through having the will to deceive, even if what one says
be true, yet inasmuch as this is a voluntary and moral act, it
contains falseness essentially and truth accidentally, and attains
the specific nature of a lie.

That a person intends to cause another to have a false opinion, by
deceiving him, does not belong to the species of lying, but to
perfection thereof, even as in the physical order, a thing acquires
its species if it has its form, even though the form's effect be
lacking; for instance a heavy bo