Siger and Thomas Discuss Their Differences
(Contact:
jan.garrett@wku.edu. This fictional conversation was created in November 2006,
for introductory teaching purposes, as part of a survey course in the history
of philosophy.)
Moderator
This is Radio Parisiensis
broadcasting from 13th Century France. I’m brother Moderatus, your moderator
for this afternoon’s discussion Ubi est veritas? (which, for our English
peasant listeners, means Where is the Truth)?
We are fortunate to have on
our panel today the leading Latin-speaking follower of Averroes of Cordova,
Siger of Brabant, whose philosophical arguments have caused quite a stir among students
in
Thomas
I am a theologian. I try to
make rational sense out of our Christian faith. Aristotle’s philosophy can help
us do that. Where our faith, in its essential matters, differs from Aristotle,
faith must be right. But there are many matters that we take on faith that are
not as clear to our intellects as they might be. Aristotle and philosophy more
generally can assist us in understanding the propositions of our faith as well
as the evidence of the senses, which tells us a great deal about the Creation.
From the perspective of theology, philosophy is a handmaiden for the faith. It
helps faith perform her proper function, which is more exalted than that of
philosophy. As a theologian, I try to keep the work of philosophy in
perspective.
Siger
I am a teacher of philosophy.
My calling is to understand what the philosophers have taught and explain those
teachings. Like anyone else who would be permitted to speak in a Christian
university today, I am also a Christian, but I do not bring the propositions of
my Christian faith into my investigations of philosophy.
Mod
Let’s go directly to the
ideas. What is your view of the relation of the Creator to Creation, Master
Siger?
Siger
As a philosopher, I learn from
The Philosopher (Aristotle) and The Commentator (Averroes), I say that God, understood as the Prime
Mover, has one immediate effect, that is, upon the first celestial
intelligence, the intellectual substance that moves the sphere of fixed stars.
The first intelligence emanates from God eternally and with necessity. This
causality proceeds downward through the other intelligences and celestial
spheres to the intelligence associated with the lunar sphere. This intelligence
is identical to the agent intellect that is present in human lives.
Moderator
And
does the Prime Mover have any other effects?
Siger
No
other direct effects. Of course, he has
many indirect effects, even in the sublunary realm.
Thomas
Like Master Siger, I affirm that
there must be a first mover, who is indeed divine. And I accept that there are
a series of intelligences that are associated with the celestial spheres and
the sphere of the Moon. But I most sharply disagree with other things Master
Siger teaches in the name of philosophy. For theology, the Prime Mover is God
the Creator who is the direct author of intelligences, the celestial spheres,
and the species of humans, animals and plants.
Siger
Philosophy teaches that the
cosmos, the celestial spheres and the intelligences, and even the species of animals
and plants here below are eternal. As I wrote in my treatise On the Eternity of
the Universe (de Aet. Mundi, ed. Bazan, Louvain/Paris, 1972).
The
human species went into being . . . by the generation of one individual before
another individual to infinity, not in some individual alone at a time when it
previously did not exist at all. (119.38-47)
There was no first man or
tree, but man begets man begets man, and tree generates tree generates tree.
Thomas
Aristotle and his followers
have at most proven that the eternity of the universe and the species of living
beings on earth is rationally possible. What is rationally possible is not an unavoidable
conclusion of reason. It is therefore not unreasonable to take on faith what
Scripture teaches, namely, that there is a beginning of Creation in time.
Moreover, although reason
cannot establish a temporal beginning of Creation, that is, that there was,
say, a day before which there was no earlier day, reason can prove that the
present existence of contingent beings like you and me derives from a first
cause, an uncaused cause.
Mod
I
understand, Master Thomas, that you defend a distinction between existence and
essence.
Thomas
Aristotle teaches that
visible beings are composed of form and matter, with form, or the soul or
essence, being actuality and matter, or the body, a potentiality to receive
form. I go one step further and insist that besides essence or form and matter,
there is also, in created beings, the act of being itself, existence or esse.
That comes directly from God.
Mod
And how about God, does He
have esse? How is that related to his divine essence?
Thomas
The essence of God includes
his esse. He is the only being for whom that is the case. Even the
intelligences, which are popularly called angels, must receive their existence
from the will of God.
Siger
This distinction between esse
and essentia is not philosophy. Aristotle does not say anything of the sort. As
I said, the divine prime mover is the direct cause of the first celestial
intelligence. He is the indirect cause of everything else. Essence and
existence are not really separable. A living being comes into existence when
its species form enters into a quantity of matter that had not been previous
informed by such a form, a body prepared to receive form by natural biological
processes.
God is utterly simple, not a
composite of esse and essentia. Creatures, and that includes the intelligences,
are compounded from matter and form, substance and accidents. God is pure act.
Creatures are not pure act, but have varying degrees of potentiality. The
farther removed from God, the more potentiality they have.
Thomas
It is true that the farther
removed from God a being is, the more potentiality and the less actuality it
has. Nevertheless, there must be an act more important than the form of a
living being. That act is the act of existence. This act directly comes from
God and is a participation of the creature in God. In other words, we owe our
very being to God. The philosophy of Master Siger fails to do justice to this
awesome fact.
Siger
As
a transmitter of philosophy, I cannot go where it does not permit me.
Mod
Tell
me about the sublunary world.
Siger
Everything that happens from
the Prime Mover on down to the lunary sphere occurs with eternal necessity. Below
this level, potentiality plays a bigger role. The consequence is that here generation
and corruption, coming to be and passing away, are unavoidable. In the
sublunary world, there is not necessity but contingency: things come to be in
certain ways, but they could have come to be otherwise.
Mod
So
there is free will?
Siger
Humans do have free will, because
what we will is not necessitated as the movements of the celestial bodies are.
But the human will is not an unmotivated power. Humans are influenced by events
in their human and physical environment, including what happens to their
bodies.
Mod
And
what of the human soul?
Siger
Man’s soul is the substantial
form of his body. There is an intellectual soul separated from the body, though
united to it. It is unified with the body as a mover is to the object it moves.
This intellectual soul is the last of the intelligences to emanate from the
Prime Mover, that is, it is an indirect—not a direct—effect of the divine
mover. It is eternal and immortal. It is common to all human beings. Each human
being bears his own special relation to this intellectual soul. If I understand
something and brother Thomas does not, then to that extent the agent intellect
is illuminating my passive intellect and not his.
Thomas
Theology does not endorse
this teaching of Master Siger.
Mod
Let
me ask one or two more questions of him first and then we shall hear your view,
Brother Thomas. Is there anything individual and immortal in the human being,
Master Siger?
Siger
It is our nature to be
associated, while alive, with the immortal intellectual soul associated with
the celestial intelligence nearest to us. But philosophy recognizes nothing
immortal about individual human beings.
Mod
If there is no afterlife for
individuals, do we have nothing to fear from our wrongdoing?
Siger
There are moral sanctions in
this life. As Aristotle teaches, a wicked person, even if he is not caught and
punished in this life, suffers from internal turmoil, since he is at odds with
his own mind, which naturally discovers for him reminders of his essence as a
social and rational being.
Mod
Thomas
Aquinas?
Thomas
The human soul is an
intellectual substance and the form of the body, both at once.
Mod
I understand that you think
of the angels as intellectual substances too.
Thomas
Yes, but their substance is
not the form of a body.
Mod
Why, if the human soul is an
intellectual substance like the angels, does it need a body?
Thomas
The human soul must have a
body because, unlike the angelic soul, the human intellectual soul is so
ordered that it can only gain knowledge when it has mental notions about which
it can reason and pass judgment. The intellect cannot reason unless it has
acquired universal notions. That means it cannot do without the prior work of the
senses, like sight, hearing, smell, and touch. But these senses in turn cannot
operate without physical organs, which enable them to acquire the sensible
forms of things. The mind generates universal notions, that is, the intelligible
forms, by abstracting them from the sensible forms stored in memory. The
celestial intelligences, on the other hand, receive their universal notions
directly from God.
Mod
And
do you agree with Siger, that the intellectual soul of all humans is one thing?
Thomas
Most assuredly not. The human
soul is unlike the souls of other living things. The souls of beasts and plants
are material forms tied up with matter. The human soul is a unique type of
soul. It is neither a material form nor an independent intellectual substance.
Moreover, with humans, the intellectual soul is individuated. There is one
soul, and that means one intellect, for each human being.
Mod
And
that makes it possible for God to hold individuals accountable in the
afterlife?
Thomas
It would certainly seem so.
Christians take individual immortality on faith. Reason can only show that it
is possible. Our faith in immortality is not unreasonable.
Mod
And
what do you gentlemen think about the agent intellect? I gather you disagree.
Siger
The agent intellect is just
another name for the common intellectual soul of humanity. It is, according to
The Commentator, identical to the last celestial intelligence.
Thomas
Not on my view. Each human
being has his own agent intellect, “the intellectual light created by God in
our soul as a likeness of the uncreated light” (Maurer, 183-84).
Mod
And you have also something
to say about the passage in Aristotle where he speaks about the possible
intellect?
Thomas
The possible intellect, to
which Aristotle refers when he says that the intellect is in a sense all
things, has two functions. First it has the function of apprehending the
essences of things and the formation of universal concepts. Secondly, it has
the function of judging that things corresponding to a particular concept
exist. Judgment affirms existence. While the first function grasps the essence
of, say, humanity, the second function enables us to judge, for instance, that
a human being exists.
Mod
Is
God aware of the future?
Siger
From a philosophical
perspective, the view is this: Because the sublunary world is the location of
so much potentiality and contingency, nobody can know future events, insofar as
they are contingent rather than necessary. Not even the Prime Mover has knowledge
of future contingent events. He does know, however, that he is the indirect
cause even of them.
Thomas
God is omniscient. He knows,
among other things, what is future to us, but, as Boethius taught, He knows
them from the perspective of eternity, which regards as present what is future
for temporal creatures.
Mod
Does
time move toward some sort of goal?
Thomas
It is a matter of our
Christian faith that history moves toward the Last Judgment and the Second
Coming of Christ. No true philosophy will contradict that.
Siger
Philosophy understands time
as cyclical. The evidence of the senses and the pronouncements of reason upon
that evidence tell us that there is no target date, as it were, at which the
nature of things aims. (See also De Aeternitate Mundi, 131.77-132.85 Bazan.)