Review of The Greatest Possible Being by Jeff Speaks

October 22, 2019

Speaks, Jeff. The Greatest Possible Being. Oxford: Oxford University Press, 2018, 175pp, $45.


In The Greatest Possible Being, Jeff Speaks takes aim at critically analyzing the method of perfect being theology. Perfect being theology is a philosophical method for developing a specific doctrine of God. In particular, the method claims to guide one’s thoughts towards deriving the divine attributes. Speaks is skeptical about the ability of this method to accomplish this task. Over the course of eight chapters, Speaks offers an analysis of metaphysical, epistemological, semantic, and theological issues related to the task of perfect being theology.

Speaks starts out by offering an introduction to the general idea of perfect being theology. According to Speaks, perfect being theology involves two basic steps in order to derive a specific conception of God through reason alone. The method is meant to help one identify which attributes are divine attributes. In step 1, a perfect being theologian selects a modal principle about God’s greatness. In step 2, a perfect being theologian selects a greatness condition that fits with the preferred modal principle. In these two easy steps, one should have a recipe for identifying which attributes are God’s.

With regards to step 1, Speaks identifies three different modal principles that a perfect being theologian might use in order to derive the divine attributes. These principles are stated as follows: 1) God is the greatest conceivable being, 2) God is the greatest possible being, and 3) God is the greatest actual being. Once a modal principle has been selected, one connects this principle with a relevant greatness condition.

In step 2, a greatness condition is meant to help the theologian identify which attributes are possessed by the greatest actual, possible, or conceivable being. Speaks claims that there are two desiderata that a greatness condition must satisfy: entailment and informativeness. With regards to entailment, it should follow from the fact that some particular property F is a great-making attribute, and the relevant modal principle, that F is a property of God’s. The informativeness desiderata states that it should be possible, without relying on prior substantive claims about God, that a candidate divine property satisfies the greatness condition.

With these distinctions in hand, Speaks claims that there is an easy way to show that a particular modal principle is false. In order to show that a particular modal principle is false, one will need to show that certain implausible properties satisfy the modal principle and the greatness condition. These implausible properties are ones that are quite obviously not divine attributes. For example, the property being a well-shaken martini is quite obviously not a divine attribute. Yet, Speaks argues that this property can satisfy different modal principles and their relevant greatness conditions. Thus, implying that the modal principle is in fact false.

As a test case, imagine that one’s preferred modal principle is that “God is the greatest actual being.” Speaks says that whatever turns out to be the greatest actual being might not be that impressive. Speaks offers the comical example of Michael Jordan. Speaks argues that the modal space for the greatest actual being in our world might be much smaller than we think. It might very well turn out that the greatest actual being in our world is Michael Jordan. Surely, says Speaks, no one will think that Jordan is God. Of course, I should think that the perfect being theologian will deny that the modal space in our world is really so small that a being like Jordan turns out to be the greatest actual being. However, Speaks will say that the method of perfect being theology, by itself, does not specify how big the modal space is, and thus the method is not useful for clearly deriving the divine attributes.

What about the other modal principles? Speaks argues the conceivability modal principle is of little help to perfect being theology. Why? Because one cannot specify the relevant sense of conceivability without making the modal principle collapse into the ‘God is the greatest possible being’ modal principle. Speaks offers a helpful analysis of different conceptions of conceivability, and the problems that each view faces.

Yet, one might wonder what is wrong with the modal principle ‘God is the greatest possible being.’ Speaks offers an assortment of arguments for why this modal principle cannot be used to derive the divine attributes. However, I often found myself thinking that Speaks has ignored some obvious moves that perfect being theologians traditionally make. One worry that I have is that Speaks has not given a proper analysis of what it means to be the greatest possible being, nor of what makes a property a great-making property.

Traditionally, theologians and philosophers have said that a proper analysis of greatness entails that God has all of the perfections, or great-making properties, in an unsurpassable way. This sort of analysis can be found in Anselm, John Duns Scotus, and Leibniz, among others. This analysis has also received a rigorous defense in Yujin Nagasawa’s recent work, Maximal God: A New Defence of Perfect Being Theism. With this analysis of greatness, the perfect being theologian then gives an analysis of what makes a property a great-making property. Typically, it is said that a great-making property is a property that it is better to have than not to have. Traditionally, this has been analyzed as identifying fundamental properties that would make any being whatsoever intrinsically better. A classic example is being powerful. Any being with the property being powerful is intrinsically better than any being that lacks the property being powerful. Further, any being that has the property of being powerful in an unsurpassable way is better than any being who lacks this.

Speaks dismisses these kinds of attempts to fill out the method of perfect being theology as being impure forms of perfect being theology. Speaks claims that this analysis of God’s greatness is an impure form of perfect being theology because it does not allow one’s selected modal principle to play any role in one’s reasoning about God’s perfection.

I find this questionable. It seems obvious that a proper analysis of ‘greatest possible being’ entails having all of the great-making properties. Moreover, I find it obvious that this understanding of greatness would play a significant role in my thinking about God’s perfection. This is evidenced by the fact that many debates in philosophical theology are about which model of God includes more great-making properties, and which involve God in having those properties in an unsurpassable way. For instance, classical theists often argue that open theism provides a less than perfect model of God because open theism denies that God has certain attributes like exhaustive foreknowledge.

However, Speaks maintains that even this impure form of perfect being theology cannot be used to derive the divine attributes. In his critique of this impure method, I found that Speaks’ discussion of the candidate great-making properties continually focused on kind-relative properties like being a well-functioning cardiovascular system, instead of fundamental properties that are intrinsically great-making, all things being equal. Traditionally, perfect being theologians have tried to clarify this point by distinguishing pure perfections from impure perfections. Speaks does offer a brief discussion of the pure/impure perfections distinction, but Speaks dismisses this as trivial.

All in all, I think that Speaks’s exact analysis of perfect being theology is less obvious than it might have been; at points it is often difficult to pin down precisely where his objections lie and from where his objections come. That being said, Speaks clearly identifies a host of problems that perfect being theologians need to avoid when developing their method. More advanced theology and philosophy students will want to consider the problems that Speaks identifies, and make sure that they avoid them. Beginning students will be better off starting with a book like Thomas Morris’ Our Idea of God, or Yujin Nagasawa’s The Existence of God. Once beginning students have mastered this material, they should be in a good position to engage with Speaks’s arguments.

R. T. Mullins

University of St Andrews

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