In this article, I will briefly argue for the following theses: (a) it is not clear that Anselm’s ontological argument in Chapter Two of Proslogium presupposes that existence is a property, and (b) Anselm’s argument presupposes that objectivity and subjectivity are properties.
It is commonly held that, in Chapter Two of Proslogium, Anselm assumed that existence is a property (hereafter, the Property Assumption or PA) and that, since the PA is false, his ontological argument as articulated in Chapter Two is unsound. Kant posed this sort of objection (hereafter, the Kantian-style Objection or KO) in his Critique of Pure Reason. It has become common for philosophers to follow Kant on this point. But is KO correct? Can Anselm’s argument be dismissed so easily?
To begin, let us consider AOA from Chapter 2:
“And indeed, we believe that you are a being than which nothing greater can be conceived. Or is there no such nature, since the fool has said in his heart, there is no God? (Psalms xiv. 1). But, at any rate, this very fool, when he hears of this being of which I speak — a being than which nothing greater can be conceived — understands what he hears, and what he understands is in his understanding; although he does not understand it to exist.
For, it is one thing for an object to be in the understanding, and another to understand that the object exists. When a painter first conceives of what he will afterwards perform, he has it in his understanding, but he does not yet understand it to be, because he has not yet performed it. But after he has made the painting, he both has it in his understanding, and he understands that it exists, because he has made it.
Hence, even the fool is convinced that something exists in the understanding, at least, than which nothing greater can be conceived. For, when he hears of this, he understands it. And whatever is understood, exists in the understanding. And assuredly that, than which nothing greater can be conceived, cannot exist in the understanding alone. For, suppose it exists in the understanding alone: then it can be conceived to exist in reality; which is greater.
Therefore, if that, than which nothing greater can be conceived, exists in the understanding alone, the very being, than which nothing greater can be conceived, is one, than which a greater can be conceived. But obviously this is impossible. Hence, there is no doubt that there exists a being, than which nothing greater can be conceived, and it exists both in the understanding and in reality.”
Notice that Anselm does not explicitly state the PA. There is no lucid statement in the text from Chapter 2 which indicates that the argument rests on the PA. So, if AOA includes the PA, then it does so implicitly or otherwise tacitly. However, it is not clear that the PA is involved in the argument. It is not evident that the argument implies the PA, nor is it clear that Anselm tacitly assumed the proposition. To examine the matter in further detail, consider the following formal representation of AOA, expressed as a reductio ad absurdum (RAA).
I will employ the following as working definitions for the argument. These terms are defined according to common usage among practicing philosophers:
Definition 1: God is the being than which nothing greater can be conceived. (Aliquid quo nihil maius cogitari possit.) I.e., God is the greatest conceivable being.
Definition 2: A property is an abstract object and, more precisely, a universal which can be exemplified by many things at once. For example, blueness and tallness and friendliness are properties. Synonyms of ‘property’ include ‘attribute,’ ‘characteristic,’ and ‘feature.’
Definition 3: Objectivity is the property of being mind-independent (i.e., an exemplification of an essence or nature in such a way that does not depend on being a mental content). For example, my neighbor’s dog and the table on which I am writing possess the property of objectivity.
Definition 4: Subjectivity is the property of being a mental content (and thus mind-dependent, epistemic, conceptual, or ideational) that is about a nature which can be exemplified, or at least seems possibly instantiated. For example, one’s thought about the Sun or desire to visit a friend have the property of subjectivity.
I will employ the following as working assumptions for the argument:
Assumption 1: The concept of God exists subjectively in the human mind; according to Anselm, even the mind of the “fool” contains the concept, since he has some understanding of it, despite denying its objective existence. It is important to note that my definition of ‘subjectivity’ (see Definition 4) entails that the mental content is about something that is at least logically possible. Applied to God, this means that AOA involves the so-called Possibility Premise, namely, that the existence of God is logically possible. If AOA involves the Possibility Premise, then AOA is modally-significant.
Assumption 2: Objectivity and subjectivity are properties and, moreover, objectivity is a great-making property.
Assumption 3: There is a difference between objectivity and subjectivity and, moreover, objectivity and subjectivity are axiologically comparable (i.e., they can be compared in terms of greatness).
Assumption 4: It is greater for a thing to possess objectivity and subjectivity than for it to possess subjectively alone.
Assumption 5: Objectivity is not identical to existence as such.
Having stated these definitions and assumptions, here is the argument:
- If God is subjectively and not objectively real, then a being can be conceived which is greater than God – namely, a greatest conceivable being which is objectively and subjectively real. (From Assumption 4)
- God is subjectively and not objectively real. (Suppose for RAA)
- Thus, a being can be conceived which is greater than God – namely, a greatest conceivable being which is objectively and subjectively real. (1, 2 MP)
- If (3), then a being can be conceived which is greater than the greatest conceivable being.
- Thus, a being can be conceived which is greater than the greatest conceivable being. (3, 4 MP)
- If (5), then the greatest conceivable being is not the greatest conceivable being.
- Thus, the greatest conceivable being is not the greatest conceivable being. (5, 6 MP)
- Thus, it is not the case that God is subjectively and not objectively real. (2-7, RAA)
- Thus, either God is not subjectively real or God is objectively real. (8, DM)
- Thus, if God is subjectively real, then God is objectively real. (9, IMP)
- God is subjectively real. (Assumption 1)
- Thus, God is objectively real. (10, 11 MP)
- If (12), then an objectively real God exists.
- Thus, an objectively real God exists. (12, 13 MP)
Again, it is not evident that AOA implies or tacitly presupposes the PA. Did Anselm himself have the PA in mind when writing the argument ca. 1077 A.D.? This is a question about Anselm’s state of consciousness when drafting the argument nearly one thousand years ago. Since we cannot be certain of the specific thoughts and beliefs he held while developing the argument, we cannot answer this question with confidence. However, regardless of what Anselm himself assumed, it seems that AOA does not require the PA.
As noted above, although AOA does not require the PA, AOA does seem to presuppose that objectivity and subjectivity are properties. If it is the case that (i) objectivity and subjectivity are genuine properties that differ from existence as such, (ii) AOA presupposes that objectivity and subjectivity are genuine properties, and (iii) AOA does not presuppose the PA, then it is plausible to hold that the KO fails. And if it fails, then a popular and long-standing concern with AOA is unwarranted. Hence, in this case, AOA is not defeated by the KO. The KO is not a knock-out punch after all; it seems to have missed the target.
In this article, I have contended that AOA does not presuppose or imply that existence as such is a property, and that AOA presupposes that objectivity and subjectivity are properties. As such, there are reasons to suspect that the KO fails, and therefore that AOA should be evaluated based on the assumption that objectivity and subjectivity are properties rather than based on the assumption that existence is a property. Given limits of space, I will not raise and respond to objections here.
 Arguably, Anselm was the first to develop an ontological argument, although not the first to write about God as a perfect being. Perfect being theology dates at least to Plato. Anselm articulated two different versions of the ontological argument. The first is found in Chapter Two of Proslogium and the second in Chapter Three. I will call the former “Anselm’s Ontological Argument” (AOA). Although I will not discuss the latter in this paper, one might call it “Anselm’s Modal Ontological Argument” (AMOA). It is not my intention to defend fully either of these arguments here. My goal is to provide reasons for holding that AOA does not presuppose that existence is a property.
 Even if it is correct that Anselm made this assumption, it is not obvious that the assumption is false. For example, see Barry Miller’s The Fullness of Being. Miller argues that existence is a property. But it is not my purpose to pursue this point here.
 See https://sourcebooks.fordham.edu/basis/anselm-proslogium.asp for the entire text of Proslogium.
 Prima facie, this argument does not imply or presuppose that existence as such is a property. However, the reader might suspect that the argument commits the fallacy of equivocation. For example, in (2), “God” is merely a subjective concept. But in (12), “God” is a concrete personal being, not a concept. Other parts of the argument shift back and forth between the two senses of “God.” I will not pursue this point here, since it is tangential to my argument.
 This would not be sufficient to prove that AOA is sound. There might be some other objection to AOA which is successful.
 I do not argue for (i) in this paper, although it seems to me that one can develop such an argument. I have provided some reasons to hold that (ii) and (iii) are true. But given limits of space, I can say no more here.