In like manner, the sensitive appetite is incited to certain passions according to certain fixed movements of the heart and the vital spirits:  wherefore the devil can cooperate in this also.  And through certain passions being aroused in the sensitive appetite, the result is that man more easily perceives the movement or sensible image which is brought in the manner explained, before the apprehensive principle, since, as the Philosopher observes (De Somno et Virgil.:  De Insomn. iii, iv), “lovers are moved, by even a slight likeness, to an apprehension of the beloved.”  It also happens, through the rousing of a passion, that what is put before the imagination, is judged, as being something to be pursued, because, to him who is held by a passion, whatever the passion inclines him to, seems good.  In this way the devil induces man inwardly to sin.

Reply Obj. 1:  Although vital functions are always from an intrinsic principle, yet an extrinsic agent can cooperate with them, even as external heat cooperates with the functions of the vegetal soul, that food may be more easily digested.

Reply Obj. 2:  This apparition of imaginary forms is not altogether outside the order of nature, nor is it due to a command alone, but according to local movement, as explained above.

Consequently the Reply to the Third Objection is clear, because these forms are received originally from the senses. ________________________

THIRD ARTICLE [I-II, Q, 80, Art. 3]

Whether the Devil Can Induce Man to Sin of Necessity?

Objection 1:  It would seem that the devil can induce man to sin of necessity.  Because the greater can compel the lesser.  Now it is said of the devil (Job 41:24) that “there is no power on earth that can compare with him.”  Therefore he can compel man to sin, while he dwells on the earth.

Obj. 2:  Further, man’s reason cannot be moved except in respect of things that are offered outwardly to the senses, or are represented to the imagination:  because “all our knowledge arises from the senses, and we cannot understand without a phantasm” (De Anima iii, text. 30. 39).  Now the devil can move man’s imagination, as stated above (A. 2); and also the external senses, for Augustine says (Qq. lxxxiii, qu. 12) that “this evil,” of which, to wit, the devil is the cause, “extends gradually through all the approaches to the senses, it adapts itself to shapes, blends with colors, mingles with sounds, seasons every flavor.”  Therefore it can incline man’s reason to sin of necessity.

Obj. 3:  Further, Augustine says (De Civ.  Dei xix, 4) that “there is some sin when the flesh lusteth against the spirit.”  Now the devil can cause concupiscence of the flesh, even as other passions, in the way explained above (A. 2).  Therefore he can induce man to sin of necessity.

On the contrary, It is written (1 Pet. 5:8):  “Your adversary the devil, as a roaring lion, goeth about seeking whom he may devour.”  Now it would be useless to admonish thus, if it were true that man were under the necessity of succumbing to the devil.  Therefore he cannot induce man to sin of necessity.