Ontological argument

The ontological argument for the existence of God (or simply ontological argument) is an a priori proof for the existence of God. The ontological argument was first proposed by the eleventh century monk Anselm of Canterbury, who defined God as the greatest possible being we can conceive. He suggested that the greatest possible being must exist in reality: a being which exists in reality is greater than one which only exists in the mind. Descartes developed the argument, suggesting that God is a "supremely perfect being" who holds all perfections. He argued that God must therefore hold the perfection of existence and, by definition, must exist. Gottfried Leibniz slightly augmented Descartes' ideas in an attempt to prove that a "supremely perfect" being is a coherent concept.

The ontological argument has been subject to numerous criticisms, initially from Anselm's contemporary, Gaunilo of Marmoutiers. Gaunilo, using the analogy of a perfect island, suggests that the ontological argument was flawed and led to impossible or incoherent conclusions. Later, Thomas Aquinas rejected the argument on the basis that humans cannot know God's nature, whilst David Hume took empirical objection to the argument, criticising its lack of evidential reasoning. He also rejects the idea that anything can exist necessarily. Immanuel Kant put forward an objection to the argument, based on what he saw as the false premise that existence is a predicate. He proposed that, as it adds nothing to the essence of a being, existence is not a predicate (or perfection) and thus a "supremely perfect" being can be conceived to not exist. Douglas Gasking presented a parody to the ontological argument, recorded and published by William Grey. Gasking uses a form of ontological argument to prove God's existence in order to demonstrate the flaws with the argument. Finally, philosophers including C. D. Broad have dismissed the coherence of a maximally great being, proposing that some attributes of greatness are incompatible with others, making a maximally great being incoherent.

In light of criticism, some philosophers have attempted to revise the ontological argument to fix the problems presented. Mulla Sadra, an Islamic philosopher, attempted to prove the existence of God through the reality of existence, concluding with God's pre-eternal necessity. Alvin Plantinga has used modal logic to propose the necessary existence of God. Alexander R. Pruss has used Sankara's dictum that if something is impossible, we can have no perception of it. Thus, if we have a conception of something, then it is possible. Finally, Paul Oppenheimer and Edward Zalta have tried using an automated theorem prover to validate Anselm's proof.

Development

Although the ontological argument may have been implicit in the works of Greek philosophers such as Plato and the Neoplatonists,^[1] the mainstream view is that the ontological argument was first clearly stated and developed by St Anselm.^{[2][3][4][5][6]} Some scholars have argued that the Islamic philosopher Avicenna (Ibn Sina) developed a special kind of ontological argument before Anselm;^[7][8] however, this position is doubted by a number of scholars.^{[9][10][11][12]}

Anselm

Anselm of Canterbury was the first to attempt an ontological argument for God's existence.

The ontological argument was first proposed by Anselm of Canterbury (1033–1109) in the second and third chapter of his Proslogion.^[13] The argument Anselm puts forward is not, however, presented in order to prove God's existence. Rather, Proslogion is more a work of meditation, in which he documents how the idea of God had become self-evident.^[14]

In Chapter 2 of the Proslogion, Aselm defines what we understand as God to be a "being than which no greater can be conceived". ^[2] Anselm suggests that we understand the concept of a "being than which no greater can be conceived" and what it brings causes to exist in the mind. The concept either must exist either only in our mind, or in our mind and in reality. If such a being exists only in our mind, then a greater being - that which exists in reality as well - can be conceived. Therefore, if we can conceive of a being that than which nothing greater can be conceived, then it must exist in reality. Therefore, a being that than which nothing greater could be conceived must exist in reality.^[15]

In Chapter 3 of the Proslogion, Anselm suggests the notion of a being which cannot be conceived not to exist (similar to the notion of a necessary being). He argues if something can be conceived not to exist, then it is not that than which nothing greater can be conceived. Consequently, that than which nothing greater can be conceived cannot be conceived not to exist. This can be read either as a gloss on the argument in Chapter 2, or as a new (and Malcolm argued superior)^[16] version of the argument, or as the first of Anselm's derivations of divine attributes from the concept of the maximally great being, in this case the attribute of necessity.^[15]

René Descartes

French thinker René Descartes composed several arguments that could be termed ontological.

René Descartes (1596–1650) composed a number of ontological arguments, which differed from Anselm's formulation. Generally speaking, it is less a formal argument than a natural intuition.

Descartes wrote in the Fifth Meditation,

But if the mere fact that I can produce from my thought the idea of something that entails everything which I clearly and distinctly perceive to belong to that thing really does belong to it, is not this a possible basis for another argument to prove the existence of God? Certainly, the idea of God, or a supremely perfect being, is one that I find within me just as surely as the idea of any shape or number. And my understanding that it belongs to his nature that he always exists is no less clear and distinct than is the case when I prove of any shape or number that some property belongs to its nature.

—Descartes,  (AT 7:65; CSM 2:45)^[17]

Descartes argues that God's existence can be deduced from his nature, just as geometric ideas can be deduced from the nature of shapes - Descartes uses the deduction of the sizes of angles in a triangle as an example. Descartes suggests that the concept of God is that of a supremely perfect being, holding all perfections fully. He proposes that existence is a perfection: it would be better to exist than not to exist. Thus, if the notion of God did not include existence, it would not be supremely perfect, as it would be lacking a perfection. Consequently, the notion of a supremely perfect God who does not exist, Descartes argues, is unintelligible. Therefore, according to his nature, God must exist.^[18]

Gottfried Leibniz

Gottfried Leibniz saw a problem with Descartes' ontological argument: that Descartes had not asserted the coherence of a "supremely perfect" being. He proposed that, unless the coherence of a supremely perfect being could be demonstrated, the ontological argument fails. Leibniz saw perfection as impossible to analyse; therefore, it would be impossible to demonstrate that all perfections are incompatible. He reasoned that all perfections can exist together in a single entity, and that Descartes' argument is still valid.^[2]

Criticisms and objections

Gaunilo

One of the earliest recorded objections to Anselm's argument was raised by one of Anselm's contemporaries, Gaunilo of Marmoutiers. He invites his reader to conceive an island "more excellent" than any other island. He suggests that, according to Anselm's proof, this island must necessarily exist, as an island which exists would be more excellent.^[19] Gaunilo's criticism does not explicitly demonstrate a flaw in Anselm's argument; rather, it argues that, if sound, so are many other argument of the same logical form which cannot be accepted.^[20]

Gaunilo offered a further criticism of Anselm's ontological argument. He suggested that the notion of God cannot, as Anselm asserted, be conceived. He argued that many theists would accept that God, by nature, cannot be fully comprehended. Therefore, if humans cannot fully conceive of God, the ontological argument cannot work.^[21]

Anselm responded to Gaunilo's criticism by suggesting that argument applied only to concepts with necessary existence. He suggested that only a being with necessary existence can fulfil the remit of "that than which nothing greater can be conceived". Furthermore, a contingent object, such as an island, could always be improved and thus could never reach a state of complete perfection. For that reason, Anselm dismissed any argument which did not relate to a being with necessary existence.^[19]

Thomas Aquinas

St. Thomas Aquinas, while proposing five proofs of God's existence in his Summa Theologica, objected to Anselm's argument. He suggested that people cannot know the nature of God and, therefore, cannot conceive of God in the way Anselm proposed.^[22] The ontological argument would only be meaningful to someone who understands the essence of God completely. Aquinas reasoned that, as only God can completely know his essence, only he can use the argument.^[23] Aquinas' rejection of the ontological argument caused some Catholic theologians to also reject the argument.^[24]

David Hume

David Hume did not believe an ontological argument was possible.

Scottish philosopher and empiricist, David Hume, argued that nothing can be proven to exist using only a priori reasoning.^[25] In his Dialogues Concerning Natural Religion, the character Cleanthes proposes this argument:

...there is an evident absurdity in pretending to demonstrate a matter of fact, or to prove it by any arguments a priori. Nothing is demonstrable, unless the contrary implies a contradiction. Nothing, that is distinctly conceivable, implies a contradiction. Whatever we conceive as existent, we can also conceive as non-existent. There is no being, therefore, whose non-existence implies a contradiction. Consequently there is no being, whose existence is demonstrable.^[26]

Hume also suggested that, as we have no abstract idea of existence (apart from as part of our ideas of other objects), we cannot claim that the idea of God implies his existence. He suggests that any conception of God we may have, we can conceive either of existing or of not existing. Existence is not a quality (or perfection), so the concept of a completely perfect being need not actually exist. Thus, he claims that it is not a contradiction to deny God's existence.^[25] Although this criticism is directed against a cosmological argument, similar to that of Samuel Clarke in his first Boyle Lecture, it can be applied to ontological arguments as well.^[27]

Immanuel Kant

Immanuel Kant

Immanuel Kant put forward a key refutation of the ontological argument in his Critique of Pure Reason (first edition, pp. 592–603; second edition, pp. 620–631).^[28] It was primarily and explicitly directed at René Descartes, but also attacked the position of Gottfried Leibniz. Kant's refutation consists of several separate but interrelated arguments, shaped by his central distinction between analytic and synthetic judgments. In an analytic judgment, the predicate expresses something that is already contained within a concept and is therefore a tautology; in a synthetic judgment, the predicate, or claim, links the concept to something outside it that is not already logically implied by it. New knowledge consists of synthetic judgments.^[29]

Kant first questions the intelligibility of the concept of a necessary being. He considers examples of necessary proposition, such as "a triangle has three angles", and rejects the transfer of this logic to the existence of God. Firstly, he argues that such necessary propositions are only necessarily true if such a being exists: if a triangle exists, it must have three angles. The necessary proposition, he argues, does not make the existence of a triangle necessary. Thus, he argued that if the proposition "X exists" is posited, it would follow that, if X exists, it exists necessarily; this does not mean that X does exist in reality.^[30] Secondly, he argues that contradictions arise only when the subject and predicate are maintained and, therefore, a judgement of non-existence cannot be a contradiction, as it denies the predicate.^[28]

Kant then proposes that the statement "God exists" must be either analytic or synthetic - the predicate must be either inside or outside of the subject, respectively. If the proposition is analytic, as the ontological argument takes it to be, then the statement would be true only because of the meaning given to the words. Kants argues that this is merely a tautology and cannot say anything about reality. Conversely, if the statement is synthetic, the ontological argument does not work, as the existence of God is not contained within the definition of God (and, as such, evidence for God would need to be found).^[31]

Kant goes on to argue that "'being' is obviously not a real predicate" ^[28] and cannot be part of the concept of something. He proposes that existence is not a predicate, or quality. This is because existence does not add to the essence of a being, merely indicating its occurrence in reality. He suggests that if he takes the subject of God with all it's predicate and then asserts that God exists, "I add no new predicate to the conception of God". He argues that the ontological argument only works if existence is a predicate; if this is not so, then it is conceivable for a completely perfect being to not exist, thus defeating the ontological argument.^[15]

In addition, Kant argues that the concept of God is not of one a particular sense; rather, it is an "object of pure thought".^[28] He presents the view that God exists outside the realm of experience and nature. Because we cannot experience God through experience, Kant argues that it is impossible to know how we would verify God's existence. This is in contrast to material concepts, which can be verified by means of the senses.^[32]

Douglas Gasking

In criticism of the ontological argument, Melbourne philosopher Douglas Gasking (1911-1994) developed his own version of the ontological argument to prove God's non-existence. The argument is not intended to be a serious attempt to prove God's non-existence; its purpose is to illustrate the problems Gasking saw with the argument.^[33] The argument was published by William Grey at the University of Queensland.^[34]

1. The creation of the world is the most marvelous achievement imaginable.
2. The merit of an achievement is the product of (a) its intrinsic quality, and (b) the ability of its creator.
3. The greater the disability (or handicap) of the creator, the more impressive the achievement.
4. The most formidable handicap for a creator would be non-existence.
5. Therefore if we suppose that the universe is the product of an existent creator we can conceive a greater being — namely, one who created everything while not existing.
6. An existing God therefore would not be a being greater than which a greater cannot be conceived because an even more formidable and incredible creator would be a God which did not exist.
7. Therefore, God does not exist.

Gasking's proposal of premise 4 is a response to Anselm's assumption that existence is a predicate and perfection. Gasking uses this logic to assume that non-existence must therefore be a disability. It is this use of Anselm's logic which allows the conclusion that God must not exist.^[33]

Graham Oppy, a philosopher of religion, has criticised the argument in the Stanford Encyclopedia of Philosophy. He suggests that, though it may be accepted that it would be a greater achievement for a non-existent creator to create something than a creator who exists, there is no reason assume that a non-existent creator would be a greater being. He continues his criticism by arguing that there is no reason to view the creation of the world as "the most marvellous achievement imaginable". Finally, he suggests that it may be inconceivable for a non-existent being to create anything at all. Thus, Oppy views Gasking's criticism as a weak parody of the ontological argument.^[2]

Coherence of a maximally great being

In his development of the ontological argument, Leibniz attempted to demonstrate the coherence of a supremely perfect being.^[2] This problem has, however, been criticised. C. D. Broad suggested that if there are two characteristics necessary for God's perfection which, are incompatible with a third, the notion of a supremely perfect being becomes incoherent. The ontological argument assumes the definition of God purported by classical theism: that God is omnipotent, omniscient and morally perfect. There exist arguments which suggest that the combination of these characteristics is logically incoherent. For example, a morally perfect being must be perfectly merciful and perfectly just. Perfect justice requires punishing every person exactly according to what they deserve; perfect mercy requires punishing some people less than they deserve. This would make moral perfection inconsistent. Furthermore, the concepts of omniscience and omnipotence could be incompatible. The problem of divine foreknowledge is that, if omniscience includes the ability to know exactly what will happen at any given moment, and free will means the ability to make free choices at any given moment, then God cannot logically know what a being with free will shall choose to do. If he does, then the being does not have free will. However, if God is omnipotent (with the ability to do anything), then he should have the ability to create being with free will. This would suggest that omniscience and omnipotence are incompatible. If any properties of a supremely perfect being are incompatible, the idea of a supremely perfect being becomes incoherent. If this is true, the ontological argument does not work.^[15]

Other criticisms

Bertrand Russell criticised the argument, asserting that "the argument does not, to a modern mind, seem very convincing, but it is easier to feel convinced that it must be fallacious than it is to find out precisely where the fallacy lies."^[35] Conversely, during his early Hegelian phase, Russell is also known to have said: "Great God in Boots! -- the ontological argument is sound!"^[36] Richard Dawkins has also rejected the argument as "infantile" and “dialectical prestidigitation”.^[37]

Revisionists

Mulla Sadra

See also: Transcendent theosophy

Mulla Sadra (c. 1571–1640) was an Islamic philosopher, influenced by Avicenna's philosophy. Sadra discussed Avicenna's arguments for the existence of God, claiming that is was not an a priori argument and rejecting the argument on the basis that existence precedes essence.^[38]

Sadra put forward a new argument, known as Argument of the Righteous (Arabic: البرهان الصديقين‎ — Al-Burhan al-Siddiqin). The argument attempts to prove the existence of God through the reality of existence, and to conclude with God's pre-eternal necessity. In this argument, a thing is demonstrated through itself, and a path is identical with the goal. In other arguments, the truth is attained from somewhere other than itself, for example from the possible to the necessary, from the originated to the eternal origin, or from motion to the unmoved mover. But in the argument of the righteous, there is no middle term other than the truth.^[39] His version of the ontological argument can be summarised as follows:^[40]

1. There is existence
2. Existence is a perfection above which no perfection may be conceived
3. God is perfection and perfection in existence
4. Existence is a singular and simple reality; there is no metaphysical pluralism
5. That singular reality is graded in intensity in a scale of perfection (that is, a denial of a pure monism).
6. That scale must have a limit point, a point of greatest intensity and of greatest existence.
7. Hence God exists.

Mulla Sadra describes this argument in Asfar as follows:^[41]

Existence is a single, objective and simple reality, and there is no difference between its parts, unless in terms of perfection and imperfection, strength and weakness… And the culmination of its perfection, where there is nothing more perfect, is its independence from any other thing. Nothing more perfect should be conceivable, as every imperfect thing belongs to another thing and needs to become perfect. And, as it has already been explicated, perfection is prior to imperfection, actuality to potency, and existence to non-existence. Also, it has been explained that the perfection of a thing is the thing itself, and not a thing in addition to it. Thus, either existence is independent of others, or it is in need of others. The former is the Necessary, which is pure existence. Nothing is more perfect than Him. And in Him there is no room for non-existence or imperfection. The latter is other than Him, and is regarded as His acts and effects, and for other than Him there is no subsistence, unless through Him. For there is no imperfection in the reality of existence, and imperfection is added to existence only because of the quality of being caused, as it is impossible for an effect to be identical with its cause in terms of existence.

Plantinga's modal form

Alvin Plantinga has presented another version of the argument. The conclusion he provides logically follows from the premises, assuming axiom S5 of modal logic - if possibly p, then necessarily possible p and if possibly necessarily p, then necessarily p. A version of his argument is as follows^[42]:

1. A being has maximal excellence in a given possible world W if and only if it is omnipotent, omniscient and wholly good in W; and
2. A being has maximal greatness if it has maximal excellence in every possible world.
3. It is possible that there is a being that has maximal greatness. (Premise)
4. Therefore, possibly it is necessarily true that an omniscient, omnipotent and perfectly good being exists.
5. Therefore (by axiom S5) it is necessarily true that an omniscient, omnipotent and perfectly good being exists.
6. Therefore, an omniscient, omnipotent and perfectly good being exists.

This argument has two controversial premises: the axiom S5 and the "possibility premise" - that a maximally great being is possible. S5 is widely accepted, though not universally so. Paul Almond criticised the argument due to the "incoherence, incorrectness and triviality" of axiom S5.^[43]

The more controversial premise is the "possibility premise". Richard M. Gale, professor emeritus of philosophy at University of Pittsburgh, argues that the "possibility premise" begs the question, because one only has the epistemic right to accept it if one understands the nested modal operators, and if one understands them within the system S5 (without which the argument fails) then one understands that "possibly necessarily" is basically the same as "necessarily".^[44]

Sankara's dictum

An approach to supporting the possibility premise in Plantinga's version of the arfument has been attempted by Alexander R. Pruss, currently of Baylor University. He starts with the 8th–9th century AD Indian philosopher Sankara's dictum that if something is impossible, we cannot have a perception (even a non-veridical one) that it is the case. It follows that if we have a perception that p, then even though it might not be the case that p, it is at least the case that possibly p. If mystics in fact perceive the existence of a maximally great being, it follows that the existence of a maximally great being is at least possible.^[45]

Automated reasoning and the Ontological Argument

In a paper published in the Australasian Journal of Philosophy, Paul Oppenheimer and Edward Zalta describe how they used an automated theorem prover called Prover9 to validate Anselm's ontological thesis. The Prover9 reasoning engine subsequently discovered a simpler formally valid (if not necessarily sound) ontological argument from a single non-logical premise.^[46]

See also

• Gödel's ontological proof for the existence of God

Notes

1. ^ "Rethinking the ontological argument: a neoclassical theistic response", by Daniel A. Dombrowski, p.7
2. ^ ^{a b c d e} Oppy, Graham (8 February, 1996; substantive revision 15 July, 2011). "Ontological Arguments". Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/ontological-arguments. 
3. ^ "Christian Theology:an introduction",by Alister E. Macgrath,p.34
4. ^ "The God Delusion",by Richard Dawkins,p.80
5. ^ "Philosophy of Religion & Religious Ethics: Study",by Robert A. Bowie,p.17
6. ^ "The Oxford handbook of philosophy of religion", by William J. Wainwright,p.80
7. ^ Steve A. Johnson (1984), "Ibn Sina's Fourth Ontological Argument for God's Existence", The Muslim World 74 (3-4), 161–171.
8. ^ Ibn Sina (Avicenna) and Malcolm and the Ontological Argument",by P.Morewedge,p234-249
9. ^ "Avicenna", by Lenn Evan Goodman, p.76
10. ^ "Avicenna and his heritage", by Jules L. Janssens, Daniel De Smet, p.254
11. ^ Philosophy of religion: an historical introduction, by Linda Trinkaus Zagzebski, p.48
12. ^ "Islamic philosophical theology: Avicenna´s proof of the existence of God as a necessarily existent being",by H.A Davidson,p.180
13. ^ Anselm of Canterbury; trans by Jonathan Barnes. "Anselm's Proslogium or Discourse on the Existence of God, Chapter 2". David Banach's homepage at Saint Anselm College. http://www.anselm.edu/homepage/dbanach/anselm.htm. Retrieved December 27, 2006. 
14. ^ McGrath, Alister E. (1999). Science & religion: an introduction. Wiley-Blackwell. pp. 89-91. ISBN 9780631208426. http://books.google.com/books?id=Ah6M7xt0FsoC&lpg=PA89&dq=ontological%20argument%20anselm&pg=PA89#v=onepage&q=ontological%20argument%20anselm&f=false. 
15. ^ ^{a b c d} Himma, Kenneth Einar (27 April 2005). "Ontological Argument". Internet Encyclopedia of Philosophy. http://www.iep.utm.edu/ont-arg. Retrieved October 12, 2011. 
16. ^ Malcolm, N. "Anselm's Ontological Arguments", Philosophical Review, 69 (1960) 41–62.
17. ^ Descartes, René. "Meditation V: On the Essence of Material Objects and More on God's Existence". Meditations on First Philosophy. http://www.classicallibrary.org/descartes/meditations/8.htm. 
18. ^ Skirry, Justin (13 September 2008). "René Descartes (1596—1650): Overview". Internet Encyclopedia of Philosophy. http://www.iep.utm.edu/descarte/#SH5b. Retrieved October 12, 2011. 
19. ^ ^{a b} Cornman, James W.; Lehrer, Keith; Sotiros Pappas, Geogre (1992). Philosophical problems and arguments: an introduction. Hackett Publishing. pp. 254-256. ISBN 9780872201248. http://books.google.com/books?id=cRHegYZgyfUC&lpg=PA254&dq=gaunilo&pg=PA254#v=onepage&q=gaunilo&f=false. 
20. ^ Cottingham, John (1986). Descartes. Blackwell Publishing. pp. 62. ISBN 0631150463. 
21. ^ Davis, Stephen T. (1997). God, reason and theistic proofs. Edinburgh University Press. pp. 27-28. ISBN 9780748607990. http://books.google.com/books?id=n4zqh10IXXsC&lpg=PA26&dq=gaunilo&pg=PA28#v=onepage&q=gaunilo&f=false. 
22. ^ Oppy, Graham (2007). Ontological Arguments and Belief in God. Cambridge University Press. pp. 122-123. ISBN 9780521039000. http://books.google.com/books?id=qg0spmMuC98C&lpg=PA122&dq=ontological%20argument%20thomas%20aquinas&pg=PA122#v=onepage&q=ontological%20argument%20thomas%20aquinas&f=false. 
23. ^ Summa Theologica Ia.Q2.A1 http://www.newadvent.org/summa/1002.htm
24. ^ Toner, P.J.. "The Existence of God". The Catholic Encyclopedia. http://www.newadvent.org/cathen/06608b.htm#IBf. Retrieved 2007-01-19. 
25. ^ ^{a b} Russell, Paul (4 October 2005). "Hume on Religion". Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/hume-religion/. Retrieved October 16, 2011. 
26. ^ Hume, David (1776).  Dialogues Concerning Natural Religion/Part 9. Wikisource. 
27. ^ Holt, Tim. "The Ontological Argument: Hume on a priori Existential Proofs". http://www.philosophyofreligion.info/humeonaprioriproofs.html. 
28. ^ ^{a b c d} Kant, Immanuel (1958) [1787]. Critique of Pure Reason. Norman Kemp Smith (2d. ed.). London: Macmillan @ Co. Ltd.. pp. 500–507. 
29. ^ McCormick, Matt (April 17, 2001). "Immanuel Kant: Metaphysics". Internet Encyclopedia of Philosophy. http://www.iep.utm.edu/kantmeta/. Retrieved October 30, 2011. 
30. ^ Grier, Michelle (February 29, 2004; substantive revision 28 February, 2007). "Kant's Critique of Metaphysics". Stanford Encyclopedia of Philosophy. http://plato.stanford.edu/entries/kant-metaphysics. Retrieved October 30, 2011. 
31. ^ Allen, Diogenes; Springsted, Eric O. (2007). Philosophy for Understanding Theology. Westminster John Knox Press. pp. 165. ISBN 9780664231804. http://books.google.co.uk/books?id=Mc5wweqfm-gC&lpg=PA165&dq=kant%20%22ontological%20argument%22%20tautology&pg=PA165#v=onepage&q=kant%20%22ontological%20argument%22%20tautology&f=false. 
32. ^ Grier, Michelle (2001). Kant's doctrine of transcendental illusion. Cambridge University Press. pp. 258. ISBN 9780521663243. http://books.google.co.uk/books?id=jjiIyXvOPAwC&lpg=PA258&ots=TtYsfctWbr&dq=kant%20ontological%20argument%20%22object%20of%20pure%20thought%22&pg=PA258#v=onepage&q=kant%20ontological%20argument%20%22object%20of%20pure%20thought%22&f=false. 
33. ^ ^{a b} Grey, William (2000). "Gasking's Proof" (PDF). Analysis 60 (4): 368–70. doi:10.1111/1467-8284.00257. http://www.uq.edu.au/~pdwgrey/pubs/gasking.pdf. 
34. ^ Dawkins, Richard (2006). The God Delusion. Houghton Mifflin Harcourt. pp. 107-108. ISBN 9780618680009. http://books.google.co.uk/books?id=yq1xDpicghkC&lpg=PA107&dq=Douglas%20Gasking%20ontological%20argument&pg=PA107#v=onepage&q=Douglas%20Gasking%20ontological%20argument&f=false. 
35. ^ Russell, Bertrand (1972). History of Western Philosophy. Touchstone. p. 536. ISBN 0-671-20158-1.  (Book 3, Part 1, Section 11)
36. ^ Autobiography of Bertrand Russell, vol. 1, 1967.
37. ^ Holt, Jim (22 October, 2006). "Beyond Belief". New York Times. http://www.nytimes.com/2006/10/22/books/review/Holt.t.html?. Retrieved November 07, 2011. 
38. ^ براهین‌اثبات‌باری
39. ^ Mulla Sadra’s Argument of the Righteous and a Critical Study of Kant and Hume’s Views on the Proofs of God’s Existence By Hamid Reza Ayatullahi
40. ^ Rizvi, Sajjad (9 June, 2009). "Mulla Sadra". Stanford Encyclopedia of Philsophy. http://plato.stanford.edu/entries/mulla-sadra/. Retrieved November 07, 2011. 
41. ^ Asfar, Vol. 6, pp. 14–16
42. ^ Plantinga, Alvin (1998). God, arguments for the existence of. In E. Craig (Ed.), Routledge Encyclopedia of Philosophy. London: Routledge. Retrieved March 03, 2007, from [1] he attributes this to Charles Hartshorne
43. ^ Almond, Paul. "A Refutation of Plantinga's Modal Ontological Argument - and why it even suggests a disproof of God" [2]
44. ^ Gale, Richard (1993). On the Nature and Existence of God. Cambridge University Press. pp. 227. ISBN 0521457238. 
45. ^ Pruss, Alexander R. (2001). "Samkara’s Principle and Two Ontomystical Arguments". International Journal for Philosophy of Religion 49: 111–120. doi:10.1023/A:1017582721225. http://bearspace.baylor.edu/Alexander_Pruss/www/papers/Samkara.html. 
46. ^ "A Computationally-Discovered Simplification of the Ontological Argument". Australasian Journal of Philosophy 89 (2): 333–349. 2011. 

References

• Hartshorne, Charles, The Logic of Perfection (LaSalle, IL: Open Court, 1962)
• Jori, Alberto, 'Die Paradoxien des menschlichen Selbstbewusstseins und die notwendige Existenz Gottes — Zu 'Cogitatio' und 'Intellectus' im Streit zwischen Anselm und Gaunilo', in: C. Viola and J. Kormos (ed.), Rationality from Saint Augustine to Saint Anselm. Proceedings of the International Anselm Conference — Piliscsaba (Hungary) 20–23 June 2002 (Piliscsaba 2005), pp. 197–210.
• Leaman, Oliver; Peter S. Groff (2007). Islamic Philosophy A-Z. Edinburgh University Press. ISBN 0748620893. 
• Logan, Ian (2009). Reading Anselm's Proslogion: The History of Anselm's Argument and its Significance Today. Ashgate. ISBN 9780754661238. 
• Gracia, Jorge J. E.; Gregory M. Reichberg and Bernard N. Schumacher (2003). The Classics of Western Philosophy: A Reader's Guide. Blackwell Publishing. ISBN 0631236112. 
• Malcolm, Norman, "Anselm's Ontological Arguments" Philosophical Review, vol. 69, no. 1 (1960), 41–62 {reprinted in: "The Existence of God (Problems of Philosophy)" edited John Hick published Macmillan 1964 ISBN 0020854501 and also in : Knowledge and Certainty: Essays and Lectures by Norman Malcolm published Cornell University Press (Dec 1975) ISBN 0801491541.}
• Plantinga, Alvin, The Ontological Argument from St. Anselm to Contemporary Philosophers (Garden City, NY: Doubleday, 1965)
• Plantinga, Alvin. God, Freedom and Evil. (Grand Rapids, Michigan: Eerdmans, 1977) pp. 85–112
• Freddoso, Alfred J. "The Existence and Nature of God". The Ontological Argument. Univ of Notre Dame Pr, 1983.

External links

• Descartes' Ontological argument entry by Lawrence Nolan in the Stanford Encyclopedia of Philosophy
• History of the ontological argument with an annotated bibliography
• Medieval Sourcebook: Gaunilo: In Behalf of the Fool, and Anselm's Reply
• Medieval Sourcebook: Philosophers' Criticisms of Anselm's Ontological Argument for the Being of God
• Paul E. Oppenheimer & Edward N. Zalta, "On the Logic of the Ontological Argument" from James Tomberlin ed., Philosophical Perspectives 5: The Philosophy of Religion (Atascadero: Ridgeview, 1991) pp. 509–529
• Gregory S. Neal, "Anselm's Ontological Argument For the Existence of God" from Grace Incarnate (1990)
• Maciej Nowicki, "Anselm and Russell" Logic and Logical Philosophy (2006) 15:355-368.
• Mulla Sadra’s Argument of the Righteous and a Critical Study of Kant and Hume’s Views on the Proofs of God’s Existence by Hamid Reza Ayatullahi.
• Brown, Paterson. "Professor Malcolm on Anselm's Ontological Arguments", Analysis, 1961.