(I continue from Part 1 last month into Aquinas’ response to the argument.)
Almost two hundred years later, St. Thomas Aquinas (1224-1274) rejected the ontological argument; he believed that God’s existence was self-evident in itself, but not to us. Aquinas asserted that we cannot know God’s essence directly, but only through his effects, thus all valid arguments for his existence will be a posteriori, not a priori. This critique centered upon Aquinas’ charge that not everyone shared the same concept of God and consequently the argument will only convince those with a similar notion. He further claimed that even if one could share the same concept of God, one would have no idea what this sequence of words really means.[i] However, the success of the ontological argument does not depend on fully understanding the concept of a “being than which none greater can be conceived.” One does not need to possess a complete understanding of a “natural number than which none larger can be imagined” to understand that there does not exist such a number. Providing the concept is coherent, even a minimal understanding is sufficient for Anselm’s argument to stand.[ii]
Several hundred years later, Immanuel Kant (1724-1804) articulated what has become the traditional argument against the ontological argument in Critique of Pure Reason. Recall premises three and four in the restructured Anselmian argument:
- Therefore, God possesses all possible great-making properties.
- Existence is a great-making property.
Kant rejected premise four on the grounds that existence does not function as a predicate. In Kant’s words:
“Being is evidently not a real predicate, that is, a conception of something which is added to the conception of some other thing. It is merely the positing of a thing, or of certain determinations in it. Logically, it is merely the copula of a judgment. The proposition, God is omnipotent, contains two conceptions, which have a certain object or content; the word is, is no additional predicate – it merely indicates the relation of the predicate to the subject. Now if I take the subject (God) with all its predicates (omnipotence being one), and say God is, or There is a God, I add no new predicate to the conception of God, I merely posit or affirm the existence of the subject with all its predicates – I posit the object in relation to my conception.”[iii]
In other words, Kant rejected the argument because existence is not a perfection. Having described a concept and stipulating that the concept exists does not add a property to the concept. When one stipulates that x instantiates a property p (such as redness in an apple), one presupposes that x exists. Kant’s criticism is a valid metaphysical point, as existence is not a great-making property because it is not a property at all; it is rather a necessary condition for the instantiation of any properties. If Kant’s criticism holds, then Anselm’s argument fails.
Anselm, however, stipulated two versions of the ontological argument in the Prosologium. The second version (one chapter later) avoids the claim that existence is a property. Anselm stated the following:
“God is that, than which nothing greater can be conceived … And [God] assuredly exists so truly, that [God] cannot be conceived not to exist. For, it is possible to conceive of a being which cannot be conceived not to exist; and this is greater than one which can be conceived not to exist. Hence, if that, than which nothing greater can be conceived, can be conceived not to exist, it is not that, than which nothing greater can be conceived. But this is an irreconcilable contradiction. There is, then, so truly a being than which nothing greater can be conceived to exist, that it cannot even be conceived not to exist; and this being thou art, O Lord, our God.[iv]
The second form of the argument is in this logical form:
- The greatest possible being possesses all possible great-making properties.
- God is the greatest possible being.
- Therefore, God possesses all possible great-making properties.
- Necessary existence is a great-making property.
- Therefore, God possess the property of necessary existence (i.e. God necessarily exists).[v]
This version of the argument seems to avoid Kant’s criticism because necessary existence as opposed to existence appears to be a valid property. This may not be clear until one realizes the claim “x necessarily exists” entails a number of claims that give properties to x. The existence of x does not depend on the existence of any other being (unlike contingent human beings) and this requires that x has the basis for its existence in its own nature.[vi] In Anselm’s first form of the argument, God possessing the property of “existence” (compared to necessary existence) does not imply that God possesses any particular properties and Kant’s argument would hold, but not against this second form.
This distinction necessary existence may not be readily apparent to the reader and warrants discussion of different forms of existence. Richard Taylor in The Ontological Argument illuminates this important aspect to the argument. There are two senses of existence: in intellectu and in re. To say that something exists in intellectu indicates that something exists in the understanding. Examples such as Pegasus, Santa Claus together with dogs, the sun and the moon exist in intellectu (whether they exist in reality or not). A concept such as a square circle can also exist in intellectu. Having a clear concept of a square circle is different than having an image of one.
The second kind of existence referred to by St. Anselm is existence in re; meaning really existing as opposed to imaginary existence. Thus examples such as dogs, the moon and the sun exist in reality (in re), while Pegasus does not. Taylor explains how this clarification can help understand Anselm’s argument as God clearly exists in intellectu. Can one stipulate in re existence from the conception of an in intellectu concept? This question is often dismissed out of hand, but Taylor states, “Yet as a matter of fact all men are perfectly accustomed to making this transition when it comes to denying the existence in re of certain things.”[vii] Going back to our example of a square circle, which can be clearly understood in intellectu as a plane four-sided figure with all of its points equidistant from the center, one can be certain no such thing exists in re. Taylor continues, “It is simply a case of showing, solely from the description of a thing, that the thing in question is impossible, and properly concluding from this that it does not, therefore, exist.”[viii]
This conclusion of non-existence of a square circle is stronger than just denying it exists, but establishes that its non-existence is necessary (in all possible worlds). This distinction is important for Anselm’s argument in understanding contingent existence, impossible existence and necessary existence. Taylor explains, “A thing exists contingently if it exists, but is such that there is no logical absurdity in affirming that it does not.”[ix] Something can also contingently non-exist assuming there is no logical incoherency in affirming that it does (e.g. Pegasus or a second moon around the earth). Impossible existence (or necessary non-existence) would apply to our square circle concept. Although a square circle exists in intellectu and can be understood from a clear definition of its nature, one can clearly ascertain that no such thing exists in re. Taylor continues, “It seemed to St. Anselm that the idea of impossible non-existence, or better, necessary existence, is also perfectly comprehensible … One can form a clear conception of God, conceived as the supreme being, or a being of such greatness that none greater can either be or be conceived. St. Anselm had no doubt that such a being exists in intellectu, for anyone but a fool can understand a clear description of God, though of course no one can comprehend such a being any more than he can comprehend the idea of a square circle. And from one’s understanding of it one can, it was clear to St. Anselm, be certain that such a being exists in re”[x] God is not defined into existence just as square circles are not defined out of existence using the same logic. God’s existence is clearly evident to one who understands what is being described.
(Next month I will continue with modal versions of the argument)
[i] St. Thomas Aquinas, Summa Theologica, (1a Q2).
[ii] This example was acquired from “Internet Encyclopedia of Philosophy” available from www.iep.utm.edu/o/ont-arg.htm; accessed Feb 11, 2005.
[iii] Immanuel Kant, Critique of Pure Reason.
[iv] St. Anselm, Proslogion Chapter III.
[v] Outline of argument taken from lecture notes from Garry DeWeese for theistic arguments in summer 2005, Biola University.
[vi] This argument was acquired from “Internet Encyclopedia of Philosophy” available from www.iep.utm.edu/o/ont-arg.htm; accessed Feb 11, 2005.
[vii] Richard Taylor in “Introduction” in The Ontological Argument (Garden City, New York: Anchor Books, 1965), xv.
[ix] Ibid., xvi.
[x] Ibid., xvii.