Handout 4 - The Cosmological Argument

Aquinas's Second Way:

(1) The natural world includes events that occur.

(2) In the natural world, every event has a cause, and no event causes itself.

(3) In the natural world, causes must precede their effects.

(4) In the natural world, there are no infinite cause/effect chains.
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(5) Therefore, there is an entity outside of nature (a supernatural being), which causes the first event that occurs in the natural world.
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(6) Therefore, God exists.

 

Aquinas's Argument for Premise (4):

(4.1) Any infinite cause/effect chain would have no first member (no “first cause”).

(4.2) If a causal chain has no first member, then it will have no later members.

(4.3) But there exists a causal chain with later members.

(4) Therefore, there are no infinite cause/effect chains.

 

Leibniz’s Argument from Sufficient Reason

The Principle of Sufficient Reason:
For anything that exists, there is a reason why it exists and why it is as it is rather than some other way.

the universe  =df.  the aggregate consisting of every contingent thing that ever did exist, does now exist, or ever will exist.

The Argument:

(1). The universe exists.

(2). If the universe exists, then there is a reason why the universe exists.

(3). If there is a reason why the universe exists, then there is something outside the universe that the universe depends upon for its existence.

(4). If there is something outside the universe that the universe depends upon for its existence, then there is a necessarily existing, creator of the universe.
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(5). Therefore, there is a necessarily existing creator of the universe.
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(6). Therefore, God exists.