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A Possible Interpretation of Proslogion 2

One of my struggles in trying to understand Proslogion 2 is how Anselm gets to the actual existence of God rather than what he arrives at in Proslogion 3, namely the inconceivability of God’s non-existence.  I’ve also struggled with the notion of using a two-place predicate like “greater than”, since Anselm tells us that if God exists in the mind alone, a greater could be conceived, i.e. to think of God as existing in reality.  Here, we are saying that we could conceive of one and the same concept in greater ways rather than conducting a comparison of the God concept to other items in the world.  The following interpretation approximates what Anselm seems to be arguing, and I would say that it is a sound argument for God’s existence.

D1. God is defined as that which cannot be conceived to admit of more greatness.
P1. For all x, if x exists in intelletu and not in re, then it can be conceived that x exists in intellectu and not in re.
P2. For all x, if it can be conceived that x exists in intellectu and not in re, then it can be conceived that x exists in intellectu and in re.
P3. For all x, if it can be conceived that x exists in intellectu and not in re and it can be conceived that x exists in intellectu and in re, then it is conceivable that x admits of more greatness.
P4. God exists in intellectu.
C. Therefore, God exists in re.


E!x ≝ x exists in re
Ix ≝ x exists in intellectu
Gx ≝ x admits of more greatness
©… ≝ it is conceivable that…

g ≝ (ɿx)~©Gx

1. (∀x)[(Ix ∧ ~E!x) ⊃ ©(Ix ∧~E!x)] (premise)
2. (∀x)[©(Ix ∧ ~E!x) ⊃ ©(Ix ∧ E!x)] (premise)
3. (∀x){[©(Ix ∧ ~E!x) ∧ ©(Ix ∧ E!x)] ⊃ ©Gx} (premise)
4. Ig (premise)
5. ~E!g (IP)
6. Ig ∧ ~E!g (4,5 Conj)
7. (Ig ∧ ~E!g) ⊃ ©(Ig ∧~E!g) (1 UI)
8. ©(Ig ∧~E!g) (6,7 MP)
9. ©(Ig ∧ ~E!g) ⊃ ©(Ig ∧ E!g) (2 UI)
10. ©(Ig ∧ E!g) (8,9 MP)
11. ©(Ig ∧~E!g) ∧ ©(Ig ∧ E!g) (8,10 Conj)
12. ©(Ig ∧ ~E!g) ∧ ©(Ig ∧ E!g)] ⊃ ©Gg (3 UI)
13. ©Gg (11,12 MP)
14. (∃x){{~©Gx ∧ (∀y)[~©Gy ⊃ (y = x)]} ∧ ©Gx} (13 theory of descriptions)
15. {~©Gμ ∧ (∀y)[~©Gy ⊃ (y = μ)]} ∧ ©Gμ (14 EI)
16. {(∀y)[~©Gy ⊃ (y = μ)] ∧ ~©Gμ} ∧ ©Gμ (15 Comm)
17. (∀y)[~©Gy ⊃ (y = μ)] ∧ {~©Gμ ∧ ©Gμ} (16 Assoc)
18. ~©Gμ ∧ ©Gμ (17 Simp)
19. E!g (5-18 IP)


[Edit: My friend, Matt, thinks my argument may be susceptible to parody.  Here is my response]

Generally, I think parodies fail because such supposed objects, like islands of which none greater can be conceived, do not really exist in the intellect for the very same reason round squares are not abstract objects in the mind.  The phrase is nonesense, and so does not pick out any object of the understanding.

Islands just are the sorts of things that admit of degrees of greatness, so are other objects used in parody. For example, islands are present in a specified location that is surrounded by water, but it is unclear how big an island should be when considering its greatness.  It certainly cannot be omnipresent and be an island.  How many trees, island beauties, or sandy beaches ought there to be on the island which cannot be conceivably greater?  

My argument can motivate this response by proving that the greatest conceivable island is not an object that exists in the intellect.  This is because specifying that there is an island than which none greater can be conceived leads to the conclusion that God is an island, and that seems like a good reductio of the idea such a concept can be conceived.

So, if we grant the parody, I could prove that island can be predicated of God, or a being than which a greater cannot be conceived. But since islands are essentially contingent and admit of degrees of greatness, island cannot be a predicate of God, who is the being than which none greater can be conceived. So, we must reject the assumption that a greatest conceivable island exists in intellectu and we can base it on the somewhat reasonable premise that God is not an island. I would argue as follows:


Lx ≝ x is an island

i ≝ (ɿx)(~©Gx ∧ Lx)

20. ~Lg (premise)
21. (∃x){{~©Gx ∧ (∀y)[~©Gy ⊃ (y = x)]} ∧ E!x} (19 theory of descriptions)
22. Ii (IP)
23. (∃x){{(~©Gx ∧ Lx) ∧ (∀y)[(~©Gy ∧ Ly) ⊃ (y = x)]} ∧ Ix} (22 theory of descriptions)
24. {~©Gμ ∧ (∀y)[~©Gy ⊃ (y = μ)]} ∧ E!μ (21 EI)
25. {(~©Gν ∧ Lν) ∧ (∀y)[(~©Gy ∧ Ly) ⊃ (y = ν)]} ∧ Iν (23 ΕΙ)
26. ~©Gμ ∧ (∀y)[~©Gy ⊃ (y = μ)] (24 Simp)
27. (∀y)[~©Gy ⊃ (y = μ)] (26 Simp)
28. (~©Gν ∧ Lν) ∧ (∀y)[(~©Gy ∧ Ly) ⊃ (y = ν)] (25 Simp)
29. ~©Gν ∧ Lν (28 Simp)
30. ~©Gν (29 Simp)
31. ~©Gν ⊃ (ν = μ) (27 UI)
32. ν = μ (30,31 MP)
33. ~©Gμ ∧ Lμ (29,32 ID)
34. (~©Gμ ∧ Lμ) ∧ (∀y)[~©Gy ⊃ (y = μ)] (27,33 Conj)
35. ~©Gμ ∧ {Lμ ∧ (∀y)[~©Gy ⊃ (y = μ)]} (34 Assoc)
36. ~©Gμ ∧ {(∀y)[~©Gy ⊃ (y = μ)] ∧ Lμ} (35 Comm)
37. {~©Gμ ∧ {(∀y)[~©Gy ⊃ (y = μ)]} ∧ Lμ (36 Assoc)
38. (∃x){{~©Gx ∧ {(∀y)[~©Gy ⊃ (y = x)]} ∧ Lx} (37 EG)
39. Lg (38 theory of descriptions)
40. ~Lg ∧ Lg
41. ~Ii (22-40 IP)

So as long as you can provide the premise that God is not an island, not a pizza, etc. the proof works to show that such objects really are not in the intellect.

A Remix of Anselm’s Conceptual Ontological Argument


D1. God is defined as the x such that there is not something, y, where y is conceivably greater than x.
P1. For all x, if x is conceivable, then there is something, y, such that either y is identical to x and y exists or there is something, z, such that z is identical to x, z does not exist, and y is conceivably greater than z.
P2. There is some x such that x is conceivable and it is not the case that there is some y such that y is conceivably greater than x.
P3. For all x and y, either x is conceivably greater than y or y is conceivably greater than x, or if it is not the case that either x is conceivably greater than y or that y is conceivably greater than x, there is some z such that z is the mereological sum of x and y, and either z is conceivably greater than x or z is conceivably greater than y.
C. God exists.1

E!x ≝ x exists
Cx ≝ x is conceivable
Gxy ≝ x is conceivably greater than y
σ<x,y> ≝ the mereological sum of x and y
g ≝ (ɿx)~(∃y)Gyx

1. (∀x){Cx ⊃ (∃y){[(y = x) ∧ E!y] ∨ (∃z)[(z = x) ∧ (~E!z ∧ Gyz)]}} (premise)
2. (∃x)(Cx ∧ ~(∃y)Gyx) (premise)
3. (∀x)(∀y){[Gxy ∨ Gyx] ∨ {~(Gxy ∨ Gyx) ⊃ (∃z)[(z = σ<x,y>) ∧ (Gzx ∨ Gzy)]}} (premise)
4. Cμ ∧ ~(∃y)Gyμ (2 EI)
5. ~(∃y)Gyμ (4 Simp)
6. (∃z)[~(∃z1)Gz1z ∧ ~(z = μ)] (IP)
7. ~(∃z1)Gz1ν ∧ ~(ν = μ) (6 EI)
8. (∀y){[Gνy ∨ Gyν] ∨ {~(Gνy ∨ Gyν) ⊃ (∃z)[(z = σ<ν,y>) ∧ (Gzν ∨ Gzy)]}} (3 UI)
9. [Gνμ ∨ Gμν] ∨ {~(Gνμ ∨ Gμν) ⊃ (∃z)[(z = σ<ν,μ>) ∧ (Gzν ∨ Gzμ)]} (8 UI)
10. (∀y)~Gyμ (5 QN)
11. ~Gνμ (10 UI)
12. ~(∃z1)Gz1ν (7 Simp)
13. (∀z1)~Gz1ν (12 QN)
14. ~Gμν (13 UI)
15. Gνμ ∨ [Gμν ∨ {~(Gνμ ∨ Gμν) ⊃ (∃z)[(z = σ<ν,μ>) ∧ (Gzν ∨ Gzμ)]}] (9 Assoc)
16. Gμν ∨ {~(Gνμ ∨ Gμν) ⊃ (∃z)[(z = σ<ν,μ>) ∧ (Gzν ∨ Gzμ)]} (11,15 DS)
17. ~(Gνμ ∨ Gμν) ⊃ (∃z)[(z = σ<ν,μ>) ∧ (Gzν ∨ Gzμ)] (14,16 DS)
18. ~Gνμ ∧ ~Gμν (11,14 Conj)
19. ~(Gνμ ∨ Gμν) (18 DeM)
20. (∃z)[(z = σ<ν,μ>) ∧ (Gzν ∨ Gzμ)] (17,19 MP)
21. (ζ = σ<ν,μ>) ∧ (Gζν ∨ Gζμ) (20 EI)
22. Gζν ∨ Gζμ (21 Simp)
23. ~Gζμ (10 UI)
24. Gζν (22,23 DS)
25. ~Gζν (13 UI)
26. Gζν ∧ ~Gζν (24,25 Conj)
24. ~(∃z)[~(∃z1)Gz1z ∧ ~(z = μ)] (6-23 IP)
25. (∀z)~[~(∃z1)Gz1z ∧ ~(z = μ)] (24 QN)
26. (∀z)[~~(∃z1)Gz1z ∨ ~~(z = μ)] (25 DeM)
27. (∀z)[~(∃z1)Gz1z ⊃ ~~(z = μ)] (26 Impl)
28. (∀z)[~(∃z1)Gz1z ⊃ (z = μ)] (27 DN)
29. {Cμ ∧ ~(∃y)Gyμ} ∧ (∀z)[~(∃z1)Gz1z ⊃ (z = μ)] (4,28 Conj)
30. Cμ ∧ {~(∃y)Gyμ ∧ (∀z)[~(∃z1)Gz1z ⊃ (z = μ)]} (29 Assoc)
31. {~(∃y)Gyμ ∧ (∀z)[~(∃z1)Gz1z ⊃ (z = μ)]} ∧ Cμ (30 Comm)
32. (∃x){~(∃y)Gyx ∧ (∀z)[~(∃z1)Gz1z ⊃ (z =x)]} ∧ Cx} (31 EG)
33. Cg (32 theory of descriptions)
34. Cg ⊃ (∃y){[(y = g) ∧ E!y] ∨ (∃z)[(z = g) ∧ (~E!z ∧ Gyz)]} (1 UI)
35. (∃y){[(y = g) ∧ E!y] ∨ (∃z)[(z = g) ∧ (~E!z ∧ Gyz)]} (33,34 MP)
36. [(ξ = g) ∧ E!ξ] ∨ (∃z)[(z = g) ∧ (~E!z ∧ Gξz)] (35 EI)
37. (∃z)[(z = g) ∧ (~E!z ∧ Gξz)] (IP)
38. (ν = g) ∧ (~E!ν ∧ Gξν) (37 EI)
39. ~E!ν ∧ Gξν (38 Simp)
40. Gξν (39 Simp)
41. (ν = g) (38 Simp)
42. Gξg (40,41 ID)
43. (∃x){~(∃y)Gyx ∧ (∀z)[~(∃z1)Gz1z ⊃ (z = x)]} ∧ Gξx} (42 theory of descriptions)
44. {~(∃y)Gyζ ∧ (∀z)[~(∃z1)Gz1z ⊃ (z = ζ)]} ∧ Gξζ (43 EI)
45. ~(∃y)Gyζ ∧ (∀z)[~(∃z1)Gz1z ⊃ (z = ζ)](44 Simp)
46. ~(∃y)Gyζ (45 Simp)
47. (∀y)~Gyζ (46 QN)
48. ~Gξζ (47 UI)
49. Gξζ (44 Simp)
50. Gξζ ∧ ~Gξζ (48,49 Conj)
51. ~(∃z)[(z = g) ∧ (~E!z ∧ Gξz)] (37-50 IP)
52. (ξ = g) ∧ E!ξ (36,51 DS)
53. (ξ = g) (52 Simp)
54. E!ξ (52 Simp)
55. E!g (53,54 ID)


1 Some aspects of this argument are influenced by Oppenheimer & Zalta (1991), i.e. the existential quantifier carries no existential import and is analogous to Anselm’s existence in intellectu whereas E! is a predicate that indicates existence in re. One weakness of Oppenheimer & Zalta’s argument is that it depends on a non-logical axiom regarding Gxy such that it is connected. In other words, either Gxy or Gyx or (x = y). This requires all individuals to stand in a greater than relationship. It is plausible, though, that two non-identical individuals could share equal greatness. I am able to derive the uniqueness of the being than which none greater can be conceived by appealing to the notion that the merelogical composite of two equally great individuals is at least greater than one of its proper parts, which I take to be a modest premise. The interesting thing about my formulation is the first premise, which distinguishes in intellectu from in re existence, and captures Anselm’s claim that a greater could be conceived than a being that exists in the understanding alone without begging the question that this greater thing actually exists—it is merely conceptually greater.  See P.E Oppenheimer & E.N. Zalta. (1991). “On the Logic of the Ontological Argument.” In Philosophical Perspectives. Vol. 5. 509-529.

Vexing Links (12/27/2015)

Happy Holidays, Merry Christmas, Happy New Year to Vexing Questions readers.  Here are some links of note:

  1. has released its latest video in its series on the existence of God: the Leibnizian Cosmological Argument (view the other videos in the series here)
  2. The Church of England released a beautiful ad featuring the Lord’s Prayer.  It was banned and created some controversy, but it is moving nonetheless.
  3. Dr. Lee Irons does a great job defending the Trinitarian perspective in a new book.  Here is an interview about his defense, hosted by Dale Tuggy.
  4. The SEP has some new articles and revisions of note: Thomas Williams revises an entry on St. Anselm, Olga Lizzini has a new article on Ibn Sina’s Metaphysics, and Jeffery Bower revises an entry on Medieval Theories of Relations.
  5. Some music I’ve been enjoying: Timothy Vajda’s As the Crow Flies, and Sigur Rós’s version of the Rains of Castamere.
  6. great philosophy website, with videos on logic.
  7. Brilliant physicist, George Ellis, is interviewed on Closer to Truth about What An Expanding Universe Means.
  8. Grasped in Thought blogs about Gaunilo’s failed objection to Anselm’s ontological argument.
  9. Maverick Philosopher has a beautiful Christmas reflection on the meaning of  the Incarnation and John 1:14.
  10. Dr. Alexander Pruss offers an interesting argument about physicalism and thinking about big numbers.

An Argument based on Maydole’s Interpretation of Proslogion 2

Robert Maydole uses definite descriptions and Russell’s theory of descriptions to explicate Anselm’s first ontological argument in Proslogion 2.  I like the idea of using definite descriptions in the argument, and broadly agree with Maydole that Anselm intends to treat “that than which none greater can be conceived” as a definite description.  I do have some issues with Maydole’s formulation, however.  1) I think of Anselm’s argument as a reductio, but that isn’t how Maydole formulates it, 2) there are extra premises in Maydole’s formulation that are ultimately unnecessary, in my opinion, e.g. his seventh premise below 3) there is a typological error’s in Maydole’s argument, which is a minor quibble, but this seems to be a common problem with Maydole’s arguments in the Blackwell Companion to Natural Theology. It doesn’t appear that the editors proofed his arguments very well, to be honest. This is not to say that Maydole’s arguments are not ingenuiously formulated.

Maydole’s argument is formulated as follows:

Ux ≝ x is understood
Sy ≝ the concept of y exists-in-the-understanding
Ex ≝ x exists-in-reality
Gxy ≝ x is greater than y
Fxy ≝ x refers to y
Dx ≝ x is a definite description
d ≝ the definite description “(ɿx) ~©(∃y)Gyx”
g ≝ (ɿx)~©(∃y)Gyx
P(Y) ≝ Y is a great-making property
©… ≝ it is conceivable that…

Here then is our logical reconstruction of Anselm’s ontological argument:

A1 The defi nite description “that than which it is not conceivable for something to be greater” is understood. (Premise)

A2 “That than which it is not conceivable for something to be greater” refers to that than which it is not conceivable for something to be greater. (Premise)

A3 The concept of whatever a defi nite description that is understood refers to has existence-in-the-understanding. (Premise)

A4 It is conceivable that something is greater than anything that lacks a great-making property that it conceivably has. (Premise)

A5 Existence-in-reality is a great making property. (Premise)

A6 Anything the concept of which has existence-in-the-understanding conceivably has existence-in-reality. (Premise)

A7 It is not conceivable that something is greater than that than which it is not conceivable for something to be greater. (Premise)


A8 That than which it is not conceivable for something to be greater exists-in-reality.

The following deduction proves that this argument is valid:


1. Dd & Ud pr
2. Fdg pr
3. (x)(y)((Dx & Fxy & Ux) ⊃ Sy) pr
4. (x1)(Y)[(P(Y) & ~Yx1 & ©Yx1) ⊃ ©(∃x2)Gx2x1] pr
5. P(E) pr
6. (x)(Sx ⊃ ©Ex) pr
7. ~©(∃y)Gyg pr
8. Fdg & ~©(∃y)Gyg 2, 7 Conj
9. (∃x)[~©(∃y)Gyx & (z)(~©(∃y)Gyx ⊃ z=x) & (Fdx & ~©(∃y)Gyx)] 8, theory of descriptions1
10. ~©(∃y)Gyν & (z)(~©(∃y)Gyz ⊃ z=ν) & (Fdν & ~©(∃y)Gyν) 9, EI
11. ~©(∃y)Gyν 10, Simp
12. Fdν 10, Simp
13. (P(E) & ~Eν & ©Eν) ⊃ ©(∃x2)Gx2ν 4 UI
14. (Dd & Fdν & Ud) ⊃ Sν 3 UI
15. (Dd & Fdν & Ud) 1, 12, Simp, Conj
16. Sν 14, 15 MP
17. Sν ⊃ ©Eν 6, UI
18. ©Eν 16, 17 MP
19. ~(P(E) & ~Eν & ©Eν) 13, 11 MT
20. ~((P(E) & ©Eν) & ~Eν) 19 Com, Assoc
21. ~(P(E) & ©Eν) ∨ ~~Eν) 20, DeM
22. P(E) & ©Eν 5, 18 Conj
23. Eν 21, 22, DS, DN
24. ~©(∃y)Gyν & (z)(~©(∃y)Gyx) ⊃ z=ν) 10 Simp
25. ~©(∃y)Gyν & (z)(~©(∃y)Gyx) ⊃ z=ν) & Eν 23, 24 Conj
26. (∃x)[~©(∃y)Gyx & (z)(~©(∃y)Gyx) ⊃ z=x) & Ex] 25 EG
27. Eg 26, theory of descriptions
(Maydole 2012, 555-557).

My version is adapted from Maydole and runs this way:

P1. Possibly, God, the x such that there is not some y such that y conceivably has greater capacities, exists in the understanding.

P2. For all x, if possibly x exists in the understanding, it is conceivable that x exists in reality.

P3. For all x, if it is not the case that x exists in reality, and x can exist in the understanding such that it is conceivable that x exists in reality, then there is some y such that y is the proposition “x exists in reality” and there is some z such that y refers to z, z can exist in the understanding and z conceivably has greater capacities than x.

C1. The x such that there is not some y such that y conceivably has greater capacities than x, i.e. God, exists in reality.

The formal deduction is as follows, let:

Cx ≝ it is conceivable that x exists in reality
Ix ≝ x exists in intellectu
Rx ≝ x exists in re
Fxy ≝ x refers to y
Gxy ≝ x conceivably has greater capacities than y
g ≝ (ɿx)~(∃y)Gyx

1. ♢Ig (premise)
2. (∀x)[♢Ix ⊃ Cx] (premise)
3. (∀x){[~Rx & (♢Ix &Cx)] ⊃ (∃y)[(y = ⌜Rx⌝) & (∃z)((Fyz &♢Iz) & Gzx)]} (premise)
4.♢Ig ⊃ Cg(2 UI)
5.♢Ig ⊃ (♢Ig & Cg) (4 Exp)
6.♢Ig & Cg (1,5 MP)
7. ~Rg (IP)
8. ~Rg & (♢Ig & Cg) (6,7 Conj)
9. [~Rg & (♢Ig & Cg)] ⊃ (∃y)[(y = ⌜Rg⌝) & (∃z)((Fyz & ♢Iz) & Gzg)](3 UI)
10. (∃y)[(y = ⌜Rg⌝) & (∃z)((Fyz & ♢Iz) &Gzg)] (8,9 MP)
11. (μ = ⌜Rg⌝) & (∃z)((Fμz & ♢Iz) & Gzg) (10 EI)
12. (Fμν &♢Iν) & Gνg (11 EI)
13. Gνg (12 Simp)
14. (∃y)Gyg (13 EG)
15. (∃x){[~(∃y)Gyx & (∀z)(~(∃y)Gyz ⊃ (z = x))] & (∃y)Gyx} (14 theory of descriptions)
16. [~(∃y)Gyμ & (∀z)(~(∃y)Gyz ⊃ (z =μ))] & (∃y)Gyμ (15 EI)
17. ~(∃y)Gyμ & (∀z)(~(∃y)Gyz ⊃ (z =μ)) (16 Simp)
18. ~(∃y)Gyμ (17 Simp)
19. (∃y)Gyμ (16 Simp)
20. (∃y)Gyμ & ~(∃y)Gyμ (18,19 Conj)
21. ~~Rg (7-20 IP)
22. Rg (21 DN)


1This line has an error and should be: (∃x)[~©(∃y)Gyx & (z)(~©(∃y)Gyz ⊃ z=x) & (Fdx & ~©(∃y)Gyx)

Maydole R. 2012. “The Ontological Argument”. In The Blackwell Companion to Natural Theology. Ed. W.L. Craig & J.P. Moreland. Malden, MA: Blackwell Publishing, pp. 555-557.

A Modest Formulation of the Ontological Argument

In this post, I have formulated Anselm’s argument for the necessary existence of a being than which none greater can be conceived.  However, I have noted that the argument depends upon a two-place “greater than” predicate that functions with something like the Neo-Platonic “Great Chain of Being” in mind.  Some thing, x, is conceived to be greater than y in the sense that x is understood to have more capacities or has an essence that can be actualized to a greater degree. For example, a plant is understood to contingently exists, grows, takes in nutrients, and reproduces. An animal is understood to be greater in the sense that it too contingently exists, grows, takes in nutrients, and reproduces, but it also has capacities like sentience, and can self-move, etc. So the greater something is, the more powers/more capacities it is understood to have. If God exists, then God would be that being which none more powerful could be conceived, which is just to say “none greater”. I find the metaphysics where a two-place “conceivably greater than” predicate can be objectively exemplified to be extremely plausible. There is an objective sense in which I have greater capacities and abilities than a flea.

The argument is as follows:

D1. Some x is an Anselmian God if and only if x is conceivable, it is not the case that there is something that is conceivably greater than x, and x necessarily exists.

P1. There is some x conceivable such that there is nothing conceivably greater than x.

P2. For all x, if the possibility of failing to conceive of x implies the possibility that x doesn’t exist, x is mentally dependent (premise).

P3. For all x, if x is mentally dependent, there is some y such that y is conceivably greater than x (premise).

P4. If there is some x such that necessarily there is some z and z is identical to x, and x is an Anselmian God, then necessarily there exists an Anselmian God.


C1. Necessarily, there is an Anselmian God.

That is the argument in ordinary language. To show that it is a formally valid syllogism, I offer the following formal deduction:


Cx ≝ x is conceived
Mx ≝ x is mentally dependent
Gxy ≝ x is conceived to be greater than y
Θx ≝ (∃x){[♢Cx & ~(∃y)♢Gyx]& ☐(∃z)(z=x)} (Def Θx)

1. (∃x)[♢Cx & ~(∃y)♢Gyx] (premise)
2. (∀x){[♢~Cx ⊃ ♢~(∃z)(z=x)] ⊃ Mx} (premise)
3. (∀x)[Mx ⊃ (∃y)♢Gyx] (premise)
4. (∃x)[☐(∃z)(z=x)& Θx] ⊃ ☐(∃x)Θx (premise)
5. (∀x){[♢Cx & ~(∃y)♢Gyx] ⊃ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (IP)
6. ♢Cμ & ~(∃y)♢Gyμ (1 EI)
7. [♢~Cμ ⊃ ♢~(∃z)(z=μ)] ⊃ Mμ (2 UI)
8. Mμ ⊃ (∃y)(♢Gyμ) (3 UI)
9. [♢~Cμ ⊃ ♢~(∃z)(z=μ)] ⊃ (♢Gyμ)(7,8 HS)
10. ♢Cμ & ~(∃y)♢Gyμ] ⊃ [♢~Cμ ⊃ ♢~(∃z)(z=μ)] (5 UI)
11. ♢~Cμ ⊃ ♢~(∃z)(z=μ) (6,10 MP)
12. (∃y)♢Gyμ (7,9 MP)
13. ♢Gνμ (12 EI)
14. ~(∃y)♢Gyμ (6 Simp)
15. (∀y)~(♢Gyμ) (14 QN)
16. ~♢Gνμ (15 UI)
17. ♢Gνμ & ~♢Gνμ (13,16 Conj)
18. ~(∀x){[♢Cx & ~(∃y)♢Gyx] ⊃ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (5-17 IP)
19. (∃x)~{[♢Cx & ~(∃y)♢Gyx] ⊃ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (18 QN)
20. (∃x) ~{~[♢Cx & ~(∃y)♢Gyx] ∨ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (19 Impl)
21. (∃x){~~[♢Cx & ~(∃y)♢Gyx] & ~[♢~Cx ⊃ ♢~(∃z)(z=x)]} (20 DeM)
22. (∃x){[♢Cx & ~(∃y)♢Gyx] & ~[♢~Cx ⊃ ♢~(∃z)(z=x)]} (21 DN)
23. (∃x){[♢Cx & ~(∃y)♢Gyx] & ~[~♢~Cx ∨ ♢~(∃z)(z=x)]} (22 Impl)
24. (∃x){[♢Cx & ~(∃y)♢Gyx] & ~[☐Cx ∨ ♢~(∃z)(z=x)]} (23 ME)
25. (∃x){[♢Cx & ~(∃y)♢Gyx] & [~☐Cx & ~♢~(∃z)(z=x)]} (24 DeM)
26. (∃x){[♢Cx & ~(∃y)♢Gyx] & [~☐Cx & ☐(∃z)(z=x)]} (25 ME)
27. [♢Cμ & ~(∃y)♢Gyμ] & [~☐Cμ & ☐(∃z)(z=μ)] (26 EI)
28. ~☐Cμ & ☐(∃z)(z=μ) (27 Simp)
29. ☐(∃z)(z=μ) (28 Simp)
30. [♢Cμ & ~(∃y)♢Gyμ] (27 Simp)
31. [♢Cμ & ~(∃y)♢Gyμ] & ☐(∃z)(z=μ) (29,30 Conj)
32. Θμ (31 Def “Θx”)
33. ☐(∃z)(z=μ) & Θμ (29,32 Conj)
34 (∃x)[☐(∃z)(z=x) & Θx] (33 EG)
35. ☐(∃x)Θx (4,34 MP)


Indeed, I find the above argument very persuasive. However, there may be some who are resistant to the notion that the two-place “conceivably greater-than” predicate can actually and objectively be exemplified. For such a person, I propose a more modest version of the argument. The more modest version is that, since C1, i.e. “☐(∃x)Θx”, is provable given P1-P4,one can argue that if P1-P4 are jointly possible, C1 is possible, and so an Anselmian God necessarily exists. This follows given S5 in modal logic, which says that ◊☐P entails ☐P. The argument can be formally proved as follows:

Let, also:

P1 ≝ (∃x)[♢Cx & ~(∃y)♢Gyx]
P2 ≝ (∀x){[♢~Cx ⊃ ♢~(∃z)(z=x)] ⊃ Mx}
P3 ≝ (∀x)[Mx ⊃ (∃y)♢Gyx]
P4 ≝ (∃x)[☐(∃z)(z=x) & Θx] ⊃ ☐(∃x)Θx
C1 ≝ ☐(∃x)Θx

36. ◊[(P1 & P2) & (P3 & P4)] (premise)
37. [(P1 & P2) & (P3 & P4)] ⊢ C1 (premise; proved by 1-35)
38. [◊[(P1 & P2) & (P3 & P4)]& {[(P1 & P2) & (P3 & P4)]⊢ C1}] ⊃ ◊C1 (premise)
39. ◊[(P1 & P2) & (P3 & P4)] & {[(P1 & P2) & (P3 & P4)] ⊢ C1} (36,37 Conj)
40. ◊C1 (38,39 MP)
41. ◊☐(∃x)Θx (40 Def “C1”)
42. ☐(∃x)Θx (41 by “S5”)

QED (again)

Since (37) is established, and (38) merely argues that if premises are jointly possible, and those premises prove some conclusion, then the conclusion is possible, (38) is relatively uncontroversial.  So, if one objects that P1-P4 are not actually true, but admits that they are at least broadly logically, or metaphysically compossible, then one ought to agree that, necessarily, an Anselmian God exists.

Colbert on Faith, Logic, Humor and Gratitude

In the video below, Stephen Colbert talks about faith, logic, and humor.  Even though Colbert says that the ontological argument is “logically perfect”, like Pascal, he does not think logic can lead to faith in God.  There must be a movement in the heart, which Colbert connects to gratitude, and which he lives out in his work as a comedian.  But it isn’t as though logic and emotion as opposed forces.  The feeling of gratitude makes sense within a worldview where there is a being than which none greater can be conceived.

When we reflect on our existence, the love we share, the struggles, the joys, the busy days, and the quiet nights, we feel we ought to give thanks.  This gratitude is not conditioned by the kind of life we have.  For we see that gratitude is often freely expressed by the most lowly among us, and we are irked when the richest and most powerful lack gratitude.  Such a duty to feel gratitude seems to exist for us all and it doesn’t matter who we are or the sort of life we have.

Now, if we ought to express an unconditioned gratitude, then we can do so.  But if we can express such gratitude, there must be at least possible that there is an object worthy of such gratitude.  It is, after all, impossible to express gratitude if there cannot be anyone to whom the gratitude is due.  So, we might say that our ability to express unconditioned gratitude is at least predicated on the possibility of there being someone worthy of such gratitude.  So, I think only a perfect being is worthy of unconditioned gratitude, and if is possible that there is such a being, such a being exists.  That is, for me, one way in which gratitude and logic connect to bolster faith.

Anyways, here is the Colbert video.  I love a comedian who can name drop Anselm and Aquinas!

None More Actual

1579 drawing of the Great Chain of Being from Didacus Valades, Rhetorica Christiana (Wikipedia, Great chain of being)

Whenever I discuss the ontological argument with my atheistic friends, I find that they always get hung up on the same word, “greater”. They want to infuse it with moral or aesthetic meaning, and so suspect that it is subjectively defined. They don’t think there is any objective way to determine that one thing is ontologically greater than another (a flea is no greater than a child and the fact that you would swat one and not the other is just based on speciesist opinions). Indeed, to fully explain what Anselm meant by the definition, we would have to develop the neo-platonic notion of the Great Chain of Being, which is far more central to the argument than most contemporary philosophers of religion realize. Nonetheless, that requires some metaphysical assumptions from which many atheists will shy away. I want to sidestep that whole discussion by using something other than “greater.” My proposal is to run the ontological argument on a “more actual” relation. I think you can still derive the traditional divine attributes from this term, but it doesn’t suffer from seeming subjective (what is more actual is an objective question).  Nonetheless, understanding what is meant by “actual” will require some metaphysics.  When discussing proofs for God, metaphysics is inescapable.

What do I mean by “more actual”? I am appealing to the distinction between act and potency in the Aristotelian-Thomistic sense of the word. For Thomas, God is the only being that is purely actual. This is because God’s essence is His existence. God is “I am”. The distinction between act and potency is an important one in the history of philosophy. It is that distinction, which allowed Aristotle to provide a response to the Eleatics, who denied change. The Eleatics argued that change was impossible because it would have to involve being arising from non-being. Since nothing comes from nothing, change cannot arise from non-being.  Instead, Aristotle said that change occurs when a potential is actualized. So, a seed can become a plant because it is potentially a plant. And it undergoes that change when it is acted upon by actual things like water, soil, heat, etc.  We see change happen all around us, and it is rooted in the nature of things.  For instance, I am potentially bald, a potential that I am slowly actualizing with every lost hair follicle.  So, while act and potency are metaphysical concepts, they are fairly close to our commonsense.  The log is potentially fire, smoke, and ash.  The log is actually hard and damp.

An ontological argument that exploits the notion of actuality is a bit odd and perhaps shocking for my Thomistic friends. It is commonly thought that Thomas Aquinas did not accept the soundness of such arguments, a point that I am not going to discuss here. Nonetheless, I think the premises of such an argument could be defended. The argument would run like this:

1. God is that than which none more actual can be conceived (definition).
2. If God exists only in the mind, something more actual than God can be conceived (premise).
3. If something more actual than God can be conceived, something more actual than God can be conceived (tautology).
4. If something more actual than God can be conceived, something more actual than ‘that which none more actual can be conceived’ can be conceived (from 1 and 3).
5. Nothing more actual than ‘that which none more actual can be conceived’ can be conceived (premise).
6. Therefore, it is not the case that God exists only in the mind (from 2,4,5).
7. If it isn’t the case that something exists only in the mind, then it exists in reality (premise).
8. Therefore, God exists in reality (from 6 and 7).

Now, there are a few premises and a definition. The definition, I think, is fair. Aquinas takes great pains to show that whatever is pure actuality has the divine attributes. So a being than which none more actual can be conceived would be purely actual, and so simple, a se, necessary, immutable, eternal, omnipotent, omniscient, and good.

Furthermore, I think (2) is defensible. Generally that which exists merely as a conception is less actual, in some way, than its counterpart in reality. You can’t be cut by the thought of a knife.  Also, (5) seems plausible. For if something more actual than ‘that than which none more actual can be conceived’, a contradiction arises. Lastly, all that is meant in (7) is that if something doesn’t just exist in the mind, that means it exists independently of our minds, which is to say that it exists in reality.  I suspect someone might say that it is a false dichotomy to insist that if something doesn’t just exist in the mind, then it must exist in reality, but I can’t think of any alternative.  And if an alternative could be found, I am sure the argument could be adjusted in the relevant ways.

One last note is to consider whether this argument is susceptible to parody.  I think it is less susceptible.  Consider Gaunilo’s island.  Could we define an island than which none more actual can be conceived?  Well, every island is a composite of act and potency by nature.  So no island can be maximally or purely actual.  One can admit that islands that exist in reality are more actual than islands that exist in the mind, but this does not mean that ‘an island than which none more actual can be conceived’ would necessarily exist, since there is no such thing.  There are, at best, islands that are more actual than other islands, but that doesn’t lead to parody.

The Ontological Argument Revisited

(Image from

Here is an exposition of Anselm’s ontological argument. One premise is adapted from Zalta and Oppenheimer (1991) On the Logic of the Ontological Argument

However, Zalta and Oppenheimer are more concerned with arguing for an historically accurate version of the argument. They are convinced by Barnes that it is anachronistic to import contemporary modal notions into the argument. Instead, they offer an exposition that purports to infer God’s existence from God’s being. Though their argument is more simple, it involves a Meinongian interpretation of existential claims such that the existential quantifier needn’t imply existential import. My version aims to have many of the strengths that Zalta and Oppenheimer’s version has without the drawbacks of a)relying upon a Meinongian interpretation, or b) using existence as a predicate.

Note: I believe, like Zalta and Oppenheimer’s argument, that premise (2) can be used to derive God’s uniqueness. I am not sure if I can directly derive each of God’s perfections, as Zalta and Oppenheimer can using their version. That will be a future project. Also, while I use modal operators in the argument, I don’t really make use of many modal axioms to make inferences (aside from equivalency inferences). I make use of modal operators, rather, because my argument has the extremely interesting feature of deriving the necessary existence of the Anselmian God from a couple of modest premises. So the operators are their so as to track a key divine attribute Anselm claims to be able to derive from the proof. I believe the derivation of this attribute makes my version immune to Gaunilo-style parodies. That is, it shows that the Anselmian premises entail a necessarily existing being, and since islands, pizzas, and pencils are not metaphysically necessary, no object within the argument’s domain of discourse can satisfy the premises and also be contingent. Again, since this argument does not use existence as a predicate, it is immune to any Kantian objection. Finally, the argument does not illicitly move from conceivability to possibility, nor does it depend upon the S5 axiom of modal logic.

The argument is as follows:

1. Something is an Anselmian God if and only if it is conceivable but not necessarily conceived, necessarily exists, and nothing can be conceived of which is greater (definition).
2. There is something conceivable such that nothing can be conceived of which is greater (premise).
3. If the possibility of failing to conceive of x implies the possibility that x doesn’t exist, there is something conceivable that is greater than x (premise).
4. Therefore, an Anselmian God exists.

The deduction is as follows:


Cx – x is conceived
Gxy – x is greater than y
Θx – x is an Anselmian God

1. (∀x){Θx ≡ ([♢Cx & ~(∃y)(Gyx & ♢Cy)] & [~☐Cx & ☐(∃z)(z=x)])} (definition)
2. (∃x)[♢Cx & ~(∃y)(Gyx & ♢Cy)] (premise)
3. (∀x){[♢~Cx ⊃ ♢~(∃z)(z=x)] ⊃ [(∃y)(Gyx & ♢Cy)]} (premise)
4. (∀x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] ⊃ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (IP)
5. ♢Cu & ~(∃y)(Gyu & ♢Cy) (2 EI)
6. [♢~Cu ⊃ ♢~(∃z)(z=u)] ⊃ [(∃y)(Gyu & ♢Cy)] (3 UI)
7. [♢Cu & ~(∃y)(Gyu & ♢Cy)] ⊃ [♢~Cu ⊃ ♢~(∃z)(z=u)] (4 UI)
8. ♢~Cu ⊃ ♢~(∃z)(z=u) (5,7 MP)
9. (∃y)(Gyu & ♢Cy) (6,8 MP)
10. Gvu & ♢Cv (9 EI)
11. ~(∃y)(Gyu & ♢Cy) (5 Simp)
12. (∀y)~(Gyu & ♢Cy) (11 QN)
13. ~(Gvu & ♢Cv) (12 UI)
14. (Gvu & ♢Cv) & ~(Gvu & ♢Cv) (10,13 Conj)
15. ~(∀x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] ⊃ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (4-14 IP)
16. (∃x)~{[♢Cx & ~(∃y)(Gyx & ♢Cy)] ⊃ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (15 QN)
17. (∃x) ~{~[♢Cx & ~(∃y)(Gyx & ♢Cy)] ∨ [♢~Cx ⊃ ♢~(∃z)(z=x)]} (16 Impl)​
18. (∃x){~~[♢Cx & ~(∃y)(Gyx & ♢Cy)] & ~[♢~Cx ⊃ ♢~(∃z)(z=x)]} (17 DeM)
19. (∃x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] & ~[♢~Cx ⊃ ♢~(∃z)(z=x)]} (18 DN)
20. (∃x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] & ~[~♢~Cx ∨ ♢~(∃z)(z=x)]} (19 Impl)
21. (∃x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] & ~[☐Cx ∨ ♢~(∃z)(z=x)]} (20 ME)
22. (∃x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] & [~☐Cx & ~♢~(∃z)(z=x)]} (21 DeM)
23. (∃x){[♢Cx & ~(∃y)(Gyx & ♢Cy)] & [~☐Cx & ☐(∃z)(z=x)]} (22 ME)
24. [♢Cu & ~(∃y)(Gyu & ♢Cy)] & [~☐Cu & ☐(∃z)(z=u)] (23 EI)
25. {Θu ≡ ([♢Cu & ~(∃y)(Gyu & ♢Cy)] & [~☐Cu & ☐(∃z)(z=u)])} (1 UI)
26. {Θu ⊃ ([♢Cu & ~(∃y)(Gyu & ♢Cy)] & [~☐Cu & ☐(∃z)(z=u)])} & {([♢Cu & ~(∃y)(Gyu & ♢Cy)] & [~☐Cu & ☐(∃z)(z=u)]) ⊃ Θu } (1 Equiv)
27. [♢Cu & ~(∃y)(Gyu & ♢Cy)] & [~☐Cu & ☐(∃z)(z=u)] ⊃ Θu (26 Simp)
28. Θu (24,27 MP)
29. (∃x)Θx (28 EG)

Lost and the Ontological Argument

Consider Gaunilo’s refutation of Anselm’s ontological argument:

…[I]t is said that somewhere in the ocean is an island, which, because of the difficulty, or rather the impossibility, of discovering what does not exist, is called the lost island. And they say that this island has an inestimable wealth of all manner of riches and delicacies in greater abundance than is told of the Islands of the Blest; and that having no owner or inhabitant, it is more excellent than all other countries, which are inhabited by mankind, in the abundance with which it is stored.

Now if some one should tell me that there is such an island, I should easily understand his words, in which there is no difficulty. But suppose that he went on to say, as if by a logical inference: “You can no longer doubt that this island which is more excellent than all lands exists somewhere, since you have no doubt that it is in your understanding. And since it is more excellent not to be in the understanding alone, but to exist both in the understanding and in reality, for this reason it must exist. For if it does not exist, any land which really exists will be more excellent than it; and so the island already understood by you to be more excellent will not be more excellent.”

If a man should try to prove to me by such reasoning that this island truly exists, and that its existence should no longer be doubted, either I should believe that he was jesting, or I know not which I ought to regard as the greater fool: myself, supposing that I should allow this proof; or him, if he should suppose that he had established with any certainty the existence of this island. For he ought to show first that the hypothetical excellence of this island exists as a real and indubitable fact, and in no wise as any unreal object, or one whose existence is uncertain, in my understanding” (Gaunilo of Marmoutiers, In Behalf of the Fool, 6).

To summarize, Gaunilo thinks that the ontological argument proves too much.  We should expect to be able to demonstrate the existence of a superlative within any class or species of a thing.  Not only would perfect islands exist, but perfect pineapples, perfect pencils, and perfect pizzas!

But Anselm is not without a response:

Now I promise confidently that if any man shall devise anything existing either in reality or in concept alone (except that than which a greater be conceived) to which he can adapt the sequence of my reasoning, I will discover that thing, and will give him his lost island, not to be lost again

But it now appears that this being than which a greater is inconceivable cannot be conceived not to be, because it exists on so assured a ground of truth; for otherwise it would not exist at all.

Hence, if any one says that he conceives this being not to exist, I say that at the time when he conceives of this either he conceives of a being than which a greater is inconceivable, or he does not conceive at all. If he does not conceive, he does not conceive of the non-existence of that of which he does not conceive. But if he does conceive, he certainly conceives of a being which cannot be even conceived not to exist. For if it could be conceived not to exist, it could be conceived to have a beginning and an end. But this is impossible (Anselm’s Apologetic In Reply to Gaunilo’s Answer In Behalf of the Fool, 3).

Admittedly, it is not very clear how Anselm’s response undercuts Gaunilo’s parody objection— at least at first blush.  The idea seems to be that whatever is “that than which a greater is inconceivable” cannot be thought to be contingent.  But islands, at least normal islands, are contingent.

Someone might decide to bite the bullet and insist that she has conceived of a necessary island.  Has she escaped Anselm’s criticism?  Interestingly enough, it seems that Anselm is willing to concede that if such a person truly has followed his line of reasoning, then such an “island” is no longer lost, but is never to be lost again.  Still, one might raise the question, “what kind of ‘island’ is it?”

The television show Lost offers an interesting perspective to this question.  Lost was well-known for referencing a wide variety of philosophic themes.  Many of the show’s characters are named after various philosophers, e.g. Locke, Rousseau, and Hume.  Recently, I stumbled across a snippet from Lostopedia that I thought was very interesting.  The author writes:

The underlying philosophy of the entire show is the 11th century discussion around what is called Anselm’s ontological argument for God and Gaunilo’s refutation using the “lost Island” argument…  And for television, a truly greater island would be one that moved in space, or in time, or even thought for itself. In fact this fallacious argument can be extended to prove the existence of anything, like tropical polar bears (Lostopedia, Philosophers/Theories).

Upon reflection, I think the show proffers insights into how one might respond to Gaunilo.  That is, if we start to imagine what kinds of attributes a perfect island should have,  the island begins to look less and less like an island, and more and more like God.  On the show, the island could cure John Locke and others, it had enormous power, it could travel through space and time, and seem to be self-aware and express intentionality.  Towards the end of the series the island seemed to be anything but an island at all!

Suppose we are able to imagine an even greater island, one that not only travels through space and time, but somehow manages to transcend it.  Perhaps this island would be morally perfect—the island on the TV certainly wasn’t.   Would the island be pure actuality?  Would it be omnipotent and omniscient, and omnipresent?  At some point our greatest “island” just happens to have an ill-selected pseudonym.  It would be more appropriate to consider it divine.  And as we reflect on its nature, we’re no longer wondering how many coconuts, beautiful hula-girls, palm trees, or secluded beaches the island should have.  When we reflect upon the phrase “that than which none greater can be conceived” we realize that it is a description that cannot be grafted onto just any other term.  When attached to terms referencing contingent things, we’re either uttering nonsense, as we do when we speak of round-squares, or we are no longer talking about a contingent thing at all.  If we  loosen up the concept sufficiently to accommodate the Anselmian phrase, we’ve traded our initial concept for the divine concept.  The very meaning of this phrase is that which blocks Anselm’s argument from proving too much.

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