Whether the Heavenly Bodies Are the Cause of Human Actions?
Objection 1: It would seem that the heavenly bodies are the cause of
human actions. For since the heavenly bodies are moved by spiritual
substances, as stated above (Q. 110, A. 3), they act by virtue
thereof as their instruments. But those spiritual substances are
superior to our souls. Therefore it seems that they can cause
impressions on our souls, and thereby cause human actions.
Obj. 2: Further, every multiform is reducible to a uniform principle.
But human actions are various and multiform. Therefore it seems that
they are reducible to the uniform movements of heavenly bodies, as to
their principles.
Obj. 3: Further, astrologers often foretell the truth concerning the
outcome of wars, and other human actions, of which the intellect and
will are the principles. But they could not do this by means of the
heavenly bodies, unless these were the cause of human actions.
Therefore the heavenly bodies are the cause of human actions.
_On the contrary,_ Damascene says (De Fide Orth. ii, 7) that "the
heavenly bodies are by no means the cause of human actions."
_I answer that,_ The heavenly bodies can directly and of themselves
act on bodies, as stated above (A. 3). They can act directly indeed
on those powers of the soul which are the acts of corporeal organs,
but accidentally: because the acts of such powers must needs be
hindered by obstacles in the organs; thus an eye when disturbed cannot
see well. Wherefore if the intellect and will were powers affixed to
corporeal organs, as some maintained, holding that intellect does not
differ from sense; it would follow of necessity that the heavenly
bodies are the cause of human choice and action. It would also follow
that man is led by natural instinct to his actions, just as other
animals, in which there are powers other than those which are affixed
to corporeal organs: for whatever is done here below in virtue of the
action of heavenly bodies, is done naturally. It would therefore
follow that man has no free-will, and that he would have determinate
actions, like other natural things. All of which is manifestly false,
and contrary to human habit. It must be observed, however, that
indirectly and accidentally, the impressions of heavenly bodies can
reach the intellect and will, forasmuch, namely, as both intellect and
will receive something from the inferior powers which are affixed to
corporeal organs. But in this the intellect and will are differently
situated. For the intellect, of necessity, receives from the inferior
apprehensive powers: wherefore if the imaginative, cogitative, or
memorative powers be disturbed, the action of the intellect is, of
necessity, disturbed also. The will, on the contrary, does not, of
necessity, follow the inclination of the inferior appetite; for
although the passions in the irascible and concupiscible have a
certain force in inclining the will; nevertheless the will retains
the power of following the passions or repressing them. Therefore the
impressions of the heavenly bodies, by virtue of which the inferior
powers can be changed, has less influence on the will, which is the
proximate cause of human actions, than on the intellect.
To maintain therefore that heavenly bodies are the cause of human
actions is proper to those who hold that intellect does not differ
from sense. Wherefore some of these said that "such is the will of
men, as is the day which the father of men and of gods brings on"
(Odyssey xviii 135). Since, therefore, it is manifest that intellect
and will are not acts of corporeal organs, it is impossible that
heavenly bodies be the cause of human actions.
Reply Obj. 1: The spiritual substances, that move the heavenly
bodies, do indeed act on corporeal things by means of the heavenly
bodies; but they act immediately on the human intellect by
enlightening it. On the other hand, they cannot compel the will,
as stated above (Q. 111, A. 2).
Reply Obj. 2: Just as the multiformity of corporeal movements is
reducible to the uniformity of the heavenly movement as to its cause:
so the multiformity of actions proceeding from the intellect and the
will is reduced to a uniform principle which is the Divine intellect
and will.
Reply Obj. 3: The majority of men follow their passions, which are
movements of the sensitive appetite, in which movements of the
heavenly bodies can cooperate: but few are wise enough to resist
these passions. Consequently astrologers are able to foretell the
truth in the majority of cases, especially in a general way. But not
in particular cases; for nothing prevents man resisting his passions
by his free-will. Wherefore the astrologers themselves are wont to
say that "the wise man is stronger than the stars" [*Ptolemy,
Centiloquium, prop. 5], forasmuch as, to wit, he conquers his passions.
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