Ontological arguments

• Anselm's ontological argument


  P1- God is the greatest conceivable being

  P2- it is greater to exist in the understanding and in reality, than existing in the understanding alone

  C1- therefore the greatest conceivable being, God, must exist in the understanding and in reality

  C2- Therefore God exists
• Descartes' ontological argument


  P1- My idea of God is of a supremely perfect being

  P2- A supremely perfect being has all perfections

  P3- existence is a perfection

  C- therefore, God must exist
• Malcolm's ontological argument 


  P1- god is an unlimited being

  P2- god's existence is either contingent, necessary, or impossible

  P3- god's existence cannot be contingent: this would mean god would be brought into or out of existence by something else, limiting God. but god is unlimited

  P4- god's existence is not impossible: this is because the concept is not self-contradictory/incoherent

  C- therefore, god's existence is necessary- god necessarily exists