Modal Ontological Argument

 

  1. Necessarily: If a perfect being exists, then it is necessary that a perfect being exists. (Premise)
  2. Itís possible that a perfect being exists. (Premise)
  3. Itís possible that it is necessary that a perfect being exists. (By 1 and 2)
  4. If it is possible that P is necessary, then P is necessary. (Premise ďS5Ē)
  5. So, it is necessary that a perfect being exists. (By 3 and 4)
  6. So, a perfect being exists.

 

 

Why 1? Because being essentially perfect and being necessarily existent are perfections.

Why 2? Hereís the rub.

Why 4? P is necsessary if and only if P is true in every possible world. What is necessary does not vary between possible worlds. So, if P is necessary in one possible world, itís necessary in all of them, and hence it is necessary in the actual world.

 

Reversed Modal Ontological Argument

1.                              If a perfect being exists, then it is necessary that a perfect being exists. (Premise)

2.                              Itís possible that no perfect being exists. (Premise)

3.                              If itís possible that no perfect being exists, then no perfect being exists. (By 1)

4.                              So, no perfect being exists. (By 2 and 3)