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 Paris lately. Our other panelist is Thomas Aquinas, Dominican friar and student of Albertus Magnus. Our panelists have written extensively about many of the same issues. They are both familiar with the recently translated works of Aristotle and have helped to make these works better known. Brother Thomas and Master Siger, how would you describe your work?

 

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.)