eason for this is because venial sin occurs in us, either
through the imperfection of the act, as in the case of sudden
movements, in a genus of mortal sin or through some inordinateness in
respect of things referred to the end, the due order of the end being
safeguarded. Now each of these happens on account of some defect of
order, by reason of the lower powers not being checked by the higher.
Because the sudden rising of a movement of the sensuality in us is
due to the sensuality not being perfectly subject to reason: and the
sudden rising of a movement of reason itself is due, in us, to the
fact that the execution of the act of reason is not subject to the
act of deliberation which proceeds from a higher good, as stated
above (Q. 74, A. 10); and that the human mind be out of order as
regards things directed to the end, the due order of the end being
safeguarded, is due to the fact that the things referred to the end
are not infallibly directed under the end, which holds the highest
place, being the beginning, as it were, in matters concerning the
appetite, as stated above (Q. 10, AA. 1, 2, ad 3; Q. 72, A. 5). Now,
in the state of innocence, as stated in the First Part (Q. 95, A. 1),
there was an unerring stability of order, so that the lower powers
were always subjected to the higher, so long as man remained subject
to God, as Augustine says (De Civ. Dei xiv, 13). Hence there can be
no inordinateness in man, unless first of all the highest part of man
were not subject to God, which constitutes a mortal sin. From this it
is evident that, in the state of innocence, man could not commit a
venial sin, before committing a mortal sin.

Reply Obj. 1: In the passage quoted, venial is not taken in the same
sense as we take it now; but by venial sin we mean that which is
easily forgiven.

Reply Obj. 2: This vainglory which preceded man's downfall, was his
first mortal sin, for it is stated to have preceded his downfall into
the outward act of sin. This vainglory was followed, in the man, by
the desire to make and experiment, and in the woman, by doubt, for
she gave way to vainglory, merely through hearing the serpent mention
the precept, as though she refused to be held in check by the precept.

Reply Obj. 3: Mortal sin is opposed to the integrity of the
original state in the fact of its destroying that state: this a venial
sin cannot do. And because the integrity of the primitive state is
incompatible with any inordinatene