Ontological Arguement

  • Created by: claude
  • Created on: 26-05-13 20:55

The Ontological Argument

What you need to know (Ed-excel)

Anselm's Main argument - first and second form (+ives and -ives)

Gaunilo and the perfect island - Anselm's counter argument 

Descartes and his version of the Onto argument

Kant - Existence is not a predicate

Modern Versions

Alvin Plantinga - Possible worlds

Norman Malcolm - If God does exist, existence is necessary

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The Ontological Argument

A Priori - Not based on experience

Deductive - If premises are true = Necessarily conclusion is true 

Analytic - Truth or falsity given by definition of terms used

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The Ontological Argument: Anselm's First Form

St Anselm Of Canterbury                                

Wrote Onto. argument in 1078

"That than which nothing greater can be conceived"

The fool in Psalm 14, who denies God, at least has a concept of God present in the mind.

Premise 1: Definition of God (The Quote).

Premise 2: If God exists in the mind alone (as an idea) then a greater being could be imagined to                    exist both in the mind and in reality.

Premise 3: This being would then be greater than God.

Premise 4: Thus God cannot exist only as an idea in the mind.

Conclusion: Therefore, God exists both in the mind (as an idea) and in reality.

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The Ontological Argument: Anselm's Second Form

Premise 1: God is the greatest possible being (Quote).

Premise 2:It is greater to be a necessary being (cannot not be) than a contingent being (can                        cease to exist).

Premise 3: If God exists only as a contingent being, God can therefore be imagined not to exist,                    then a greater being could be imagined that cannot be conceived not to exist.

Premise 4: This being would then be greater than God.

Premise 5: God is therefore a necessary being.

Conclusion: Therefore God must exist in reality

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Strengths and Weaknesses of Anselm's Argument


  • Its is a deductive argument. If valid, it will provide proof for both believers and atheists
  • Its a starting point is valid for both believer and atheist. the definition of (Quote) is accepted by the atheist, as the atheist must have an understanding of God in order to be able to reject belief in God.
  • It is an intellectually stimulating argument that continues to be studied and debated. it is reasonable to assume, therefore, that there are good reasons to consider the argument in some way to be sound.


The idea of God as (Quote) is : 

  • Not coherent - How can God be omniscient? He cannot know human future choices (problem of free-will).
  • Mutually inconsistent - No being could be both omniscient and omnipotent, since an omnipotent being could make a creature who had a secret unknown to anyone but itself, while and omniscient being must know every secret.
  • Leading to a useless God - even supposing we can make sense of the great-making properties and show them to be mutually consistent, won't the concept of God arrive at be so distant from religious experience as to be useless?
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Strengths and Weaknesses of Anselm's Argument Cont

  • Assumed by Anselm to be beyond criticism - However, it cannot be assumed that this is the only logical way of defining God. For the process theologians, for example, a better definition of God is as 'the fellow sufferer who understands'. 


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Gaunilo and The Perfect Island

Premise 1: I can think of an island that then which no greater island can be thought.

Premise 2: Such an island must possess all perfections.

Premise 3: Existence is a perfection.

Premise 4: Therefore, the island exists.


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Anselm's Criticisms to Gaunilo

1) The island can always be added to, to make it more perfect. E.g. more sun, bluer ocean, more trees etc. And it is also subjective.

2) The island is contingent whereas God is necessary.

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Descartes and The Perfect Being

  • Reformulated the ontological argument, in terms of the concept of necessary existence.
  • Cogito, ergo sum (i think therefore i am)

Premise 1: I exist.

Premise 2: In my mind, i have the concept of a perfect being. 

Premise 3: As an imperfect being, i could not have conjured up the concept of a perfect                   being.

Premise 4: The concept of a perfect being must therefore have originated from the                            perfect being itself.

Premise 5: A perfect being must exist in order to be perfect.

Conclusion: Therefore, a perfect being exists.

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Kant Existence is not a Predicate

  • Fundamental to both Anselm's and Descartes' form of the ontological argument is that existence is a predicate - an attribute or quality that can be possessed or lacked.
  • However Kant observed that existence is not associated with the definition of something, since it does not add to our understanding of that thing.
  • Kant's position was that existence added nothing to the concept of a thing or being. For example £100 in the imagination was not made greater in number or nature. However, arguably £100 in reality is substantially more usefull than £100 in the mind since it has practical value.
  • In the same way, God who exists only in the mind can have no real effect on the lives of believers. God who exists in reality can intervene in people's lives and make a real difference.


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Modern Versions of The Ontological Argument

Norman Malcolm

Norman Malcolm proposed a form of the argument in support of necessary existence working on the presumption that if God could exist, he does exist, since he cannot not exist.

Premise 1: God is that than which nothing greater can be thought.

Premise 2: Necessary existence is a perfection.

Premise 3: If God possesses all perfections he must possess necessary existence.

Premise 4: A necessary being cannot not exist.

Premise 5: If God could exist then he would exist necessarily.

Premise 6: Its is contradictory to say that a necessary being does not exist.

Conclusion: God must exist

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Modern Versions of The Ontological Argument

Alvin Plantinga

If God's existence is necessary then he must exist in all worlds and have all the characteristics of God in them all. Plantinga argued, God is both Maximally great and Maximally excellent.

Premise 1: There exists a possible world in which there exists a being of maximal greatness and                    excellence.

Premise 2: If a maximally great and excellent being exists in one world the it must exist in all                          possible worlds, or else it would not be maximally great and excellent.

Premise 3: Our World is a possible world. Therefore, the maximally great and excellent being                        must exist in our world too.

Conclusion: Therefore God exists

(http://www.philreinhardt.com/downloads/SuperSqueezePages/Super%20Squeeze%20Page%20Pack/BonusMoreAnimatedArrows/More%20Animated%20Arrows/Arrow%20Down%201/Arrow%20Down%201%20Small/ArrowDownBlueGloss.gif)Counter Argument

We could think of a maximally great and evil being - must that also exist?

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