Jonathan Schaffer has recently argued that the traditional debate concerning monism was a debate concerning whether the first of the following theses is true rather than a debate over whether the second is true:
Priority Monism (PM): The world is fundamental (i.e., is a substance in the traditional sense--it does no depend on anything else for its existence), while every proper part of the world depends on the world for its existence.
Existence Monism (EM): The world has no proper parts.*
Now I think that (PM) and (EM) are both false (or at least have serious doubts about their truth), largely because I am inclined to think that "the world" is a non-denoting definite description; that is, I am inclined to say that there is no such thing as the world. Schaffer's paper is still quite interesting, however. Furthermore, my most recent reading of it made me think about whether there are any connections between Schaffer's discussion and the doctrine of divine simplicity.
The doctrine of divine simplicity is usually formulated as follows:
The Doctrine of Divine Simplicity (DDS): God has no proper parts and each of God's properties is identical to God.
(DDS) is, I think, a pretty bad view (and not just because the view that there is such a thing as God is a pretty bad view). Assuming that God exists, it does not seem implausible that God has proper parts. (One heterodox interpretation of the doctrine of the Trinity is that God has the three persons of the Trinity as proper parts, which contradicts (DDS).) Worse, if (DDS) is true, then:
-God is a property,
-God instantiates himself, and
-I instantiate God. (After all, both God has the property of being self-identical. So, if (DDS) is true, then God is identical to the property of being self-identical. But I instantiate the property of being self-identical. Therefore, if (DDS) is true, then I instantiate God.)
Now what Schaffer's paper got me wondering about is this. Consider the following thesis:
The Doctrine of Divine Simplicity* (DDS*): Every proper part of God and every property of God depends on God for its existence.
While (DDS) is the analogue of (EM), (DDS*) is the analogue of (PM). So if the traditional debate concerning monism was a debate concerning the truth of (PM) rather than the truth of (EM), then perhaps the traditional debate over the divine simplicity was a debate concerning the truth of (DDS*) rather than the truth of (DDS). Furthermore, even if the traditional debate over divine simplicity was
not a debate about the truth of (DDS*) but was rather a debate about the truth of (DDS), (DDS*) is a more plausible thesis than (DDS). For one thing, suffers from none of the problems for (DDS) noted above. For another, it is strongly suggested by other, not terribly implausible, traditional views.
Take the claim that every proper part of God depends on God for its existence. As Schaffer argues, Aristotle--and presumably Aquinas as well--held that each of a living thing's proper parts is dependent upon that living thing for its existence. Thus, given the claim that God is alive, which I take to be a traditional view, it follows that every proper part of God depends on God for its existence.
Next, take the claim that every property of God depends on God for its existence. According to one traditional view, properties depend upon the schmubstances that instantiate them for their existence. (A schmubstance is a substance in Aristotle's second sense; that is, it is something that has properties (or stands in relations) but is not itself a property (or a relation).) Thus, according to this view, the property of being green depends upon the green schmubstances for its existence; this is a dependence relation that obtains between a property and a plurality. Now take any property P of God. According to this view, P depends for its existence on the schmubstances that instantiate it, bbs, and God is one of bbs. Now this doesn't quite get us to the view that P depends on God for its existence. Rather, it gets us to the view that P depends on bbs for its existence, and although God is one of bbs, another schmubstance may also be one of bbs. However, another traditional view is the view that every other schmubstance depends upon God for its existence. And the following is a plausible principle: for any x, y, and zzs, if x depends on zzs for its existence and each thing that is one of zzs is either identical to y or depends on y for its existence, then x depends on y for its existence. It follows from this principle, the claim that properties depend on the schmubstances that instantiate them for their existence, and the claim that every other schmubstance depends on God for its existence that P depends upon God for its existence. But P was an arbitrarily chosen property of God. So it follows from that principle and those two traditional (and not terribly implausible) views that every property of God depends upon God for its existence.
Putting the conclusions of the last two paragraphs together, both the claim that every proper part of God depends on God for its existence and the claim that every property of God depends on God for its existence follow from traditional, and not terribly implausible, views (plus a very plausible principle concerning pluralities and dependence). But these two claims together entail (DDS*). So (DDS*) follows from traditional, and not terribly implausible, views.
*See "Monism", available on Schaffer's website, for his argument. My formulation of existence monism differs from the formulation Schaffer gives. Schaffer's formulates existence monism as follows: For all x, x is identical to the world. My formulation is superior to Schaffer's because, at least as I interpret him, Schaffer does not take the world to be the mereological fusion of absolutely everything. Rather, he takes it to be the mereological fusion of absolutely every concrete entity. Given this, the debate concerning existence monism is, it seems to me, a debate over whether the fusion of absolutely every concrete entity has any proper parts, and thus evidence in favor of the existence of abstract entities is irrelevant to the debate. However, given Schaffer's formulation, evidence in favor of the existence of abstract entities
is relevant to the debate. An alternative formulation of (EM), given that the world is the mereological fusion of absolutely every concrete entity, is: For all concrete entities x, x is identical to the world.