AVICENNA'S COSMOLOGICAL ARGUMENT FOR GOD'S EXISTENCE

(a) exists necessarily

or

(b) exists contingently.

(2) Everything that exists contingently has a reason or cause outside of itself that is responsible for its coming into being.

(This is the definition of "to exist contingently.")

(3) If the reason for something that exists contingently is also contingent, then either

(a) there is a further reason that is contingent, in a chain extending to infinity

or

(b) the chain culminates in a necessary being.

(4) If there were a chain of contingent beings extending to infinity, nothing would exist.

(Nothing that is contingent comes into existence except because of a reason.)

(5) There is something that exists contingently.

(Anything composite and material will do, such as a piece of paper.)

(6) Therefore, there is a necessary being.

(Question: From what premises above does this follow? Why does Avicenna see himself as entitled to the "Therefore"?)

(7) The necessary being is God.

(But is any necessary being necessarily God?)

THE UNICITY OF GOD

(1) If there are two distinct necessary beings, A and B: their distinctness would be either

(a) an essential attribute

or

(b) an accidental attribute.

(2) All accidental attributes have reasons or causes.

(3) If A (or B) has the distinctness as a matter of an accidental attribute, then it would not be a necessary being--an absurdity

(A would be both necessary and not necessary--which is absurd).

(4) If A (or B) has the distinctness as a matter of an essential attribute, then it is a compound being (with a division in its essence).

(5) All compound beings are contingent (depending on a reason or cause for the compounding).

(6) Neither A nor B can be a necessary being and compounded.

(7) Therefore there are no two distinct necessary beings.

(Distinctness can be neither an accidental nor essential attribute of a necessary being.)

(8) Therefore God, the necessary being, is one alone.