Phl 349

Lecture #13

Proofs of God’s Existence: The Al-Falsafa Movement

I. Aristotle

The entire body of Aristotle’s philosophical works were translated into Latin and introduced into Western Europe during the period of 1100-1270. Christian Arabs had translated Aristotle’s works into Arabic during the period of 750-900. There were four centers of exchanges between the Muslim and Western Christian worlds: Syria (during the First Crusade), Constantinople (modern-day Istanbul, capital of the Christian Byzantine Roman empire), the Norman kingdom of Sicily, and, most important of all, Spain after its reconquest by Christians during the 11^th century.

As I mentioned last week, early medieval thinkers in Western Europe had access to two logical works of Aristotle, the Categories and On Interpretation. These gave rise to the “old logic” in which Anselm and Abelard were schooled. The “new logic”, based on Aristotle’s logical treatises, the Prior Analytics and the Posterior Analytics, developed in the mid 12^th century. It was discussed by John of Salisbury (one of Abelard’s students). Aristotle’s scientific works (in biology, physics and astronomy) reached western Europe in the late 12^th century. Along with Aristotle’s works came philosophical treatises and commentaries on Aristotle written by Moslem and Jewish philosophers in the 10^th through 12^th centuries, to which we will now turn.

These Moslem and Jewish philosophers can be divided into two groups: those who accepted Aristotle’s doctrine that the universe is eternal (the al-falsafa philosopher), and those who rejected this idea in favor of a creation event (Maimonides and the kalam philosophers). The first group included al-Farabi (d. 950), Avicenna or ibn Sina (980-1037), and Averroes or ibn Rushd (1126-1198).

When Aristotle was translated into Arabic, two neo-Platonic works were incorrectly attributed to him: the Liber de Causis (derived from some of Proclus’s work), and the “Theologica Aristoteles” (which was, in fact, books IV-VI of Plotinus’s Enneads). In addition, an influential commentary on Aristotle by a Neo-Platonist, Alexaner of Aphrodisias, was also translated at the same time. These facts encouraged Jewish and Moslem philosophers to attempt a synthesis of Plato and Aristotle into a single system.

II. Al-Farabi (d. 950, Baghdad).

Al-Farabi’s most important contribution was the formulation of a real distinction between “essence” (what a thing is, its nature) and “existence” (the fact that a thing exists in actuality). This enabled him to distinguish in a new way between contingent and necessary beings, leading to a novel argument for God’s existence. Aristotle recognized a logical or conceptual difference between essence and existence in the Posterior Analytics (92b3-18): a scientific definition can prove what is the essential nature of a thing, but it cannot prove that the thing exists. What a thing is and that it is are two different matters. It is possible to understand the essence of a thing (for example, that the essence of thunder is violent motion in the air) without knowing whether the thing actually exists (what could understand what thunder is without knowing whether thunder is ever an actual phenomenon).

However, a logical distinction does not necessarily constitute a real or ontological distinction. For example, we can distinguish logically between water (the clear, tasteless and odorless fluid found in abundance on the earth) and H2O. You could know that a glass contains water without knowing that it contains H2O, and vice versa. However, there is no real distinction between the two: as a matter of fact, water just is H2O. Similarly, one could hold that there is only a logical, and not a real, distinction between essence and existence. We can distinguish between our ideas of essence and existence, but it could be that, in the real world, they are one and the same thing. Socrates’ essence (humanity) might also be responsible for his actual existence. By organizing Socrates’ matter into a living human body, Socrates’ essence constitutes his existence.

Al-Farabi, however , argued that there was a real distinction between essence and existence. For al-Farabi, an essence, like humanity or equinity, has in itself only a potential relationship to existence. The essence of humanity means that there could possibly be humans, not that there actually are humans. For humanity to have actual instances, real human beings, something has to happen. This happening is called an “act of existence”. For beings like humans, that consist of the combination of an essence or form with a mass of suitable matter, the act of existence is what is responsible for making or that blob of matter into an actual instance of humanity.

For Aristotle, there was no need for a separate act of existence. Instead, the form itself was a kind of act or happening. The individual form of this or that human being, his individual bit of the human essence, makes a blob of matter into an actual human. The form actualizes the matter, there’s no need for something else (an act of existence) to actualize the form.

It follows from Aristotle’s way of thinking about this that it is simply inconceivable that there should be such a thing as the human essence but no actual human beings. Similarly, there just couldn’t be such a thing as the essence of dinosaurs, dinosaurity, except as the actual form of appropriate bits of matter, each of which constitutes an actual dinosaur. This didn’t pose a problem for Aristotle, since he assumed that the physical universe was infinitely old, and that it had always been in exactly the form it is now, with the very same collection of animal and plant species.

However, al-Farabi assumes that it’s conceivable that the essence of dinosaurity or humanity have no actual instances at all. In this way of thinking about essence, an essence in itself is simply a possible way for actual things to be. To produce instances of an essence, the essence must be combined with individual acts of existence. Hence, within each instance of the essence, each individual man, dinosaur or horse, we can distinguish two real components: the essence of the thing, and the existence of the thing.

Al-Farabi’s way of putting this is to say that existence is an “accident” that has been added to an essence. We’ve talked about accidents before. Medieval philosophers, following Aristotle’s Categories, assumed that the world contains individual accidents. For example, if Socrates is pale, then there is an individual accident, namely, Socrates’ individual paleness, that is in some sense “in” Socrates. Even if Plato is pale in exactly the same way, with exactly the same shade of white, Socrates and Plato have two separate individual accidents: Socrates’ paleness is in Socrates, and Plato’s paleness is in Plato. The two individual accidents can be instances of the very same universal form of paleness, but the individual accidents are particular things, not universals.

Scholastic philosophy organizes things into the following four categories:

	Particulars	Universals
Substances	Socrates	Man
Accidents	Socrates’ paleness	Paleness itself

Nominalists deny that anything really belongs to the second column (the column of universal things, like Man or Paleness), but everyone in the medieval world took for granted that there were both particular substances, like Socrates, and particular or individual accidents, like Socrates’ paleness or wisdom.

You might note that something seems to be missing from the table. On the second row, we have both Paleness (the universal) and Socrates’ paleness (a particular accident). On the first row, we have Man (the universal), but instead of Socrates’ humanity, we have Socrates himself. What happened to Socrates’ individual humanity, the humanity that’s “in” Socrates? Medieval philosophers will say that Socrates’s humanity is his essence, and a substance’s essence isn’t “in” the substance in the same way that accidents are. Socrates isn’t identical to his own paleness: his paleness has been somehow “added” to Socrates. However, Socrates’ humanity can’t have been “added” to Socrates in this same way, because it is impossible to so much as think of Socrates stripped of his very humanity. Being human is what Socrates must fundamentally is: there can be no real distinction between Socrates and his own humanity, as there can be between Socrates and his own paleness.

Now, that was long digression through the topic of accidents, but it was a digression that was going to be needed sooner or later anyway. Let’s return to al-Farabi’s statement that existence is an “accident” that has been added to essence. This is just al-Farabi’s way of making the point that there is a real distinction between an essence and the actuality of its instances. In principle, we can separate the two, and consider the essence apart from all of its actual instances. The fact that the essence has any real instances at all is something that can be added to the essence itself; hence, it is an “accident” of the essence. Consider, for example, the statements “Human beings exist.” Does this statement predicate something of humanity? Yes, al-Farabi insists. Existence is a predicate applied here to humanity.

What about Socrates’ existence? Is that an accident of Socrates? That’s a difficult question, which al-Farabi doesn’t address, and that we’ll simply put off for the time being.

Once we have the real distinction between essence and existence, there arises the possibility of two fundamentally different kinds of being: those whose essence involves or implies existence, and those whose essence does not involve existence. Or, to put it another way, al-Farabi has established that in ordinary beings, like horses or humans, there is a real distinction between essence and existence. However, this leaves open the possibility that there might be an extraordinary kind of being for which there was no such real distinction: a being whose essence was identical to its existence. Al-Farabi calls those beings whose essence does not involve existence “per se contingent” beings (beings that are contingent “in and of” themselves), and he calls those beings whose essence does involve existence “per se necessary” beings (beings that are necessary in and of themselves). We know there are per se contingent beings, but are there any per se necessary beings?

Here, al-Farabi does not do what Anselm does: he does not claim that we can prove that per se necessary beings exist by simply defining an essence (like that of a thing no greater than which can be conceived) that does involve existence, by its very definition, and then reasoning, as Anselm did, that such a being must actually exist, since to think otherwise would be to contradict the definition itself. Instead of trying to define or even to conceive of the essence of a per se necessary being, al-Farabi instead makes use of a variation on Aristotle’s First-Cause (or “cosmological”) argument to prove that there must exist at least one such being.

III. Ibn Sina

Ibn Sina made several important contributions to the development of the cosmological (first-cause) argument. First, he defined a “necessary being” as one whose non-existence would imply a contradiction. This seems to make the necessity of God’s being a matter of logical necessity, suggesting Anselm’s argument that God’s existence is somehow guaranteed by pure logic alone. However, ibn Sina doesn’t argue directly from the definition of necessary being to its actual existence, as Anselm does. Thus, the necessity of God’s being is not the necessity that follows from definitions and pure logic. Rather, the necessity of God’s being is a kind of factual necessity, one that can be recognized only by seeing that contingent beings require a necessary cause.

Second, ibn Sina was the first in the history of the cosmological argument to recognize that this proof does not depend on the assumption that an infinite regress of causes is impossible. Instead, in his book, al-Najat, ibn Sina asks us to consider the entire series of per se contingent causes, whether this series is finite or infinite. Let’s call this series S. By its very definition, S includes all of the per se contingent causes that are connected to our present experience. Now, ibn Sina asks this question: is S itself per se contingent or per se necessary? If S were per se necessary, then there would be a necessary being that is wholly composed of contingent things, which is absurd. If S were contingent, then S itself would require a cause. The series of S must either be within S or outside it. If the cause of S were inside it, then this thing would cause itself, which is impossible. So, the cause of S must be outside the series. But this means that the cause of S must be a necessary being, since S, by definition, already includes all of the contingent causes connected to our world. Thus, the world must have a necessary cause.

Third, ibn Sina makes clear that what contingent beings is not a cause for their beginning to exist, but a cause for their existing right now. Contingent beings require a continual, sustaining cause of their existence at every moment. This is how ibn Sina reconciles Aristotle’s insistence that the universe must have a first cause with his belief that the universe is eternal, without beginning or end. Ibn Sina’s God is not needed to explain the beginning of the universe (since there was no beginning) – instead, God is needed to sustain the universe of contingent beings in existence at every moment.

Ibn Sina derives a number of familiar corollaries from his argument. First, he contends, along the lines developed by Plotinus, that there can be only one necessary being. If there were two necessary beings, they would have to differ either in essence or in accidents. A necessary being cannot have any accidents, since this would make it composite and so contingent. However, as Plotinus argued, there cannot exist two distinct beings, each of which is absolutely simple in essence and lacking any accidents, since nothing would differentiate one from the other. Second, ibn Sina concludes that the first cause must be uncaused. Finally, the first cause must be absolutely perfect, since imperfection results from combining negation with being. Since the first cause is absolutely simple, it must be free from all negation, guaranteeing its perfection.

IV. Ibn Rush (Averroes)

In The Incoherence of the Incoherence, ibn Rushd gave what he took to be the correct form of the cosmological argument, a version of the argument from contingency as proposed by al-Farabi and ibn Sina. Ibn Rushd defines a “contingent” being as one that begins to exist. A necessary being is simply an eternal being. Contingent beings must be caused, and the chain of causes must ultimately terminate in a necessary (eternal) being.

Like ibn Sina, ibn Rushd believed that the universe itself was eternal, without beginning or end. The kind of contingent beings we see today have always existed, reproducing after their own kind in endless cycles. Thus, ibn Rushd believed that certain kinds of causes can form infinite series, without a first member. For example, each of us has an infinite number of human ancestors, each procreated by a preceding generation. However, ibn Rushd insisted that there are two kinds of series of causes: “essential” series and “accidental” series. A cyclical series of generations is an accidental series, and this kind of series can regress to infinity. However, each contingent thing has,not only an accidental cause, but also an essential one, and a series of essential causes must always terminate in a first cause.

This distinction between accidental and essential causes also has its roots in Aristotle. Aristotle argued that each newborn human being has two causes: his father and the sun. The father is only an accidental cause of his child, since the father is a cause of the child’s coming into existence, but the child can continue to exist even if the father passes away. The sun, however, is a cause, both of the child’s coming into existence and its continuing to exist throughout its life. Essential causation is always simultaneous causation: causation at this very moment. Ibn Rushd interprets Aristotle as requiring the first cause as the cause of the continued existence of contingent things. Only an eternal being requires no cause of its continuing to exist: contingent beings, that can be both created and destroyed, require some explanation for their existence at each moment during which they happen to persist.

However, since ibn Rushd defines necessity in terms of eternity, and not in terms of absolute simplicity, he is unable to demonstrate that the first cause of the universe is absolutely perfect and beyond our comprehension. Instead, he accepts Aristotle’s conception of God as a self-absorbed intellect who inspires eternal motion on the part of the heavenly spheres. Thus, God is limited to an astronomical, rather than a religious or metaphysical function.