Shiur #11: Proofs for the Existence of God
A. Rambam's Proofs for the Existence of God
In Book I of his Guide of the Perplexed, the Rambam addresses mainly the problem of religious language. He focuses on two fundamental issues: the negation of God's corporeality and the descriptions of divine attributes. Regarding both of these subjects, he tries to solve an apparent contradiction between what the philosophical principle dictates and what the actual biblical text states. The Rambam provides very decisive responses to these issues in Book I, and he presents an exegetical approach that applies his conclusions to the study of the text.
In Book II of the Guide, the Rambam moves on to address problems of greater philosophical and theological complexity. He introduces Book II with some philosophical proofs for the existence of God, proposing two main proofs.
The first rests upon the fundamental principles of Aristotelian philosophy. At the beginning of Book II, the Rambam lists twenty-six assumptions of Aristotelian philosophy. The first is the negation of infinity, which is, in fact, the foundation of Aristotle's main proof for the existence of the "First Cause," as we discussed in the previous shiur.
Aristotle devoted much attention to causal relations in the world, emphasizing that every event has a cause. At the same time, he maintained that an infinite chain of causes is impossible in reality, since the very concept of infinity here is a paradox. The inescapable conclusion arising from these two assumptions is that there must be a First Cause, which is not caused by anything else – i.e., it is the initial, original source of all movement and change in the world. The causal chain thus has a starting point. This First Cause cannot be something physical, nor can it be connected in any way to physicality, because it is the source of eternal motion. Anything related to the physical is limited and thus cannot be eternal. This is proof of the existence of a First Cause that is a non-physical entity; it is form without substance, or – in religious language – God.
The second basic proof that the Rambam presents arises from a different philosophical tradition. The Rambam relates it to Aristotle, but in fact its source may be traced to the teachings of the Muslim philosopher Avicenna (Ibn Sina). According to his philosophy, God is a necessary existence in view of reality. As we have discussed previously, all creations in the world have "possible existence." It is possible for them to exist, and it is possible for them not to exist. People are born because their parents happened to meet and marry, and they continue to exist for a thousand other similar reasons. A sudden change in the weather, a slight tremor of the earth, a tiny mutation of DNA – and the being ceases to exist. But God is a "necessary existence" – in other words, His existence is not dependent on anything outside of Himself; it is a necessary fact, entailed by His essence.
How does Avicenna arrive at the conclusion that there is something which possesses necessary existence? The Rambam explains. For everything whose existence is merely possible, there exists some possibility that its existence will cease. Moreover, it is possible to calculate the chances that two things which both have possible existence, will cease to exist at the same time. One might likewise calculate the chances that three things possessing possible existence might cease to exist at the same time, or four things, and so on. But in an infinite stretch of time, all possibilities must come to pass, even if their probability is very low. Therefore, if the world has existed forever, as Aristotle posited, there must have been at least one time when all things with possible existence ceased to be, at the same moment. But since we see that the world continues to exist, we must conclude that there is something that has necessary existence, which cannot be terminated or disappear, and it is this entity that is responsible for the positive existence of the world.
This proof leads elegantly to the conclusion that this entity with necessary existence is a simple unity that is in no way compound or complex. How so? Anything that is compound cannot have necessary existence, for there is some cause or reason extraneous to it which brings together its two (or more) elements, and that external reason is the cause of its existence. Apple with honey does not have necessary existence, since something must join the apple and the honey; in the absence of a conscientious host, there will be no apple and honey to eat. Therefore we must conclude that the entity with necessary existence cannot be complex or compound.
B. Criticism of the Approach of Logical Proofs for God's Existence
Much discussion and criticism have surrounded the proofs that the Rambam brings for God's existence. Many scholars have attempted to refute or support them. What I wish to discuss here is not the criticism that rejects his proofs because of some logical contradiction or inconsistency, but rather one that rejects the very idea of such proofs, whatever their degree of persuasiveness.
Let us first consider the view of Rav Yehuda Ha-levy, as set forth in Sefer Ha-kuzari:
“Now I understand the difference between the names ‘Elo-him’ and ‘Y-H-V-H,’ and I see what a great distance there is between the God of Abraham and the God of Aristotle. Man yearns for God as a matter of conviction and on the basis of eye-witness evidence, while one is drawn to Elo-him on the basis of logical speculation. One who perceives God in the former manner is ready for self-sacrifice out of love of God and is willing to give up his life for it. Speculation, however, implies only that God should be venerated so long as this entails no harm and one suffers no pain on this account. (Sefer Ha-kuzari IV:16)
Rav Yehuda Ha-levy argues that recognizing God through logical proofs leads to a perception of God as a piece of information: I know that the moon exists, I know that the sun exists, and I know that God exists – after all, I can prove it! But of what value is the proof if it does not arouse any religious devotion and enthusiasm?
Rav Yehuda Ha-levy casts the difference between "the God of Avraham" and "the God of Aristotle" – between the believer and the philosopher – in even sharper terms. Many years later, his concepts were repeated by the French philosopher and scientist Blaise Pascal. On Nov. 23, 1654, Pascal experienced a vision. He wrote down what he had seen on a piece of paper, sewed the paper into his coat, and for eight years (until his death) he transferred the paper from one coat to another, never mentioning its existence to anyone. It was found only after his death, and thus the world found out about the central event in the life of this outstanding scientist and philosopher. He wrote:
In the year of our Lord 1654, on Monday, November 23rd, Saint Clיment’s Day, from approximately 10:30 in the night until approximately half an hour after midnight. Fire. The God of Abraham, the God of Isaac, the God of Jacob. Not of the philosophers and the scholars. Certainty, certainty, emotion. Joy. Peace…
The teaching of Rav Yehuda Ha-levy and the testimony of Pascal are of tremendous importance. For hundreds of years the medieval scholars tried to bridge the chasm separating Greek philosophy and revealed religion. The fruit of their labor is the religious philosophy of the Middle Ages. This philosophy – the pinnacle of which, in the Jewish world, is represented by the Rambam's thought – located the metaphysical motifs in Aristotelian philosophy and identified them with elements of revealed religion. Aristotle's "First Cause" was identified with God; the "spheres" were the angels, etc. Rav Yehuda Ha-levy sets forth here the fundamental flaw inherent to this entire way of thinking. The motivation of the philosopher is entirely different from the motivation of the believer. The philosopher wishes to know; the believer wishes to serve God. When the brilliant French scientist Laplace presented his scientific views before Napoleon, the king asked him: Where is God in this explanation of how the universe works? To this Laplace replied, "It works without that assumption." This demonstrates that even those philosophers and scientists who included God in their worldview gave Him a completely different role from that recognized by the religious world.
This applies not only to medieval philosophy. In our days, too, not everyone who believes in God is religious. Yehuda Amichai's poem, "God's Fate," expresses this idea:
Is now like the fate
Of trees and stone, sun and moon,
In whom people stopped believing
When they began to believe in Him.
But He must stay with us
At least like the trees, at least like the stones,
And the sun and the moon and the stars.
Amichai notes a simple psychological fact: just as the sun may exist in our world without us becoming sun worshippers, so God can exist in our world without us being worshippers of Him.
Rav Yehuda Ha-levy, too, tried to prove God's existence – not through cold, logical reasoning, but rather using an historical-traditional line of argument, based on the idea that perception via tradition is comparable to sensory perception. In other words, a person who arrives at a recognition of God through tradition, experiences closeness to God as though he himself had been present at the Revelation. This experience arouses within him a love for God and readiness to serve Him.
Rav Soloveitchik expressed criticism of logical proofs for God's existence along the same lines as that of Rav Yehuda Ha-levy:
We do not deny that there is a certain difference between past and present ways of thinking about seeking the infinite through finite reality. Whereas medieval and early modern philosophy expressed the search for infinity and eternity in objective terms – by formulating ostensibly decisive, logically valid proofs – the contemporary conception dares to deny the logical, objective validity of these proofs…The contemporary conception asserts that we have no right to use these categories, which result from our finite, contingent, temporal existence, to prove the truth of an infinite, absolute, eternal reality…
However, while this conception was intended to uproot and deny, it found itself implanting and affirming. It denied the possibility of using logical proofs to make indirect inferences from finitude to infinity, from temporality to eternity, and from actuality to transcendence. But instead of abolishing all these proofs, it accepted them anew as immediate experiences that are not based on logical inferences, but rather are manifested in sudden revelations and insights. These experiences have nothing in common with indirect inference or logical deduction. Just as consciousness of the world in general, and of the self in particular, do not involve logical demonstrations but constitute the spiritual essence of man, so too with the experience of the divine. It is totally aboriginal, the beginning and end of man’s reality. It is forever prior to inference or deduction. 
Rav Soloveitchik is talking about the revolution wrought in religious thought by Immanuel Kant. Kant proved that it is impossible to prove the existence (or non-existence) of God. Rav Soloveitchik argues that in so doing, Kant in no way damaged religious belief. On the contrary – he liberated it from the burden of logical proof, which had been a foreign implant in religious faith. Faith, according to Rav Soloveitchik, is based on an inner certainty, not on any sort of logical proof. The experience of the encounter with God cannot rest upon logical proof. No one among us needs logical proof that his mother exists, or that he himself exists. Likewise, there is no need for a logical proof for the existence of God. Faith does not contradict reason, but it likewise does not rest upon it.
Translated by Kaeren Fish
 These are the first and the third proofs that he lists. The second is rather questionable, and the fourth is a variation of the first.
 Cf. Camus' assertions: "I have never seen a man die for the sake of an ontological claim. Galileo, who maintained an important scientific truth, was quick to deny it the moment it placed his life in danger" (A. Camus, The Myth of Sisyphus, 1942).
And From There You Shall Seek, trans. Naomi Goldblum (NJ: 2008), pp. 11-12.