Sunday, November 10, 2013

A Simplicity Objection to the Moral Argument from Ontological Simplicity

Brief Recap

In part 1 of the moral argument I noted that morality appeared to exist as part of the nonphysical realm to at least some degree (e.g. moral wrongness is a nonphysical property), that morality is metaphysically necessary (e.g. kindness is a good thing in all possible worlds), and I argued that if we posited just one nonphysical thing as the foundation for objective morality and tried to find the simplest explanation for that entity grounding objective moral values and obligations, we end up with an eternal, transcendent, metaphysically necessary entity that imposes moral duties upon us with supreme and universally binding authority. This observation (and the claim that it rationally supports theism to at least some degree) is what I’ve called the argument from ontological simplicity.

The Challenge

One could challenge whether the ontological explanation I proposed (a single metaphysically necessary entity) really is the simplest explanation. But since, in an attempt to coincide with Ockham’s razor, I posited only one entity in my explanation and ascribed it only with those properties needed to simply explain the explananda, what could be simpler?

Part of simplicity, or at least Swinburnian simplicity, is positing fewer types of entities. In the explanation that I gave for the argument from ontological simplicity, I posited a metaphysically necessary entity, i.e. one that exists in all possible worlds. Yet contingent entities (those that exist in some possible worlds but not all) are what we are really familiar with. So instead of having an ontology where just contingent entities exist, my explanation adds a new type of entity: a metaphysically necessary one. So, a simpler explanation would be to just have multiple contingent entities spread about in different possible worlds grounding morality because this explanation would be positing fewer types of entities.

The Rebuttal

There are a number of problems with this objection. First, it should be noted that the argument from ontological simplicity only posits one entity—and thus only one type of entity—in explaining morality’s metaphysical necessity. The explanation contains only one type of entity: a necessary one. It doesn’t posit a mixture of contingent and necessary entities.

Still, I think that problem can be overcome to at least some degree. One of the factors in assessing the quality of an explanation is how well it fits with background knowledge, and as I pointed out before simplicity plays a role in how well a theory fits with background knowledge. Ceteris paribus we are to prefer theories that fit our background knowledge more simply in a way that provides for a simpler overall worldview. For example, when discovering a new chemical compound, it is possible that instead of electrons surrounding the atomic nuclei, those surrounding particles are different particles that behave in an empirically identical way to electrons, and then get transformed into electrons if they ever leave the compound. This would involve positing a new type of particle however, and it’s simpler to posit that the negatively charged particles surrounding the atomic nuclei are electrons, since that would yield a worldview with fewer types of entities. Similarly, our background knowledge consists of contingent entities but no metaphysically necessary entities, and so it would be simpler to posit contingent entities instead of metaphysically necessary ones.

Even this amended objection has problems. First, whether there are metaphysically necessary entities in one’s background beliefs will depend on the person. Second, how does one weigh the simplicity of having just one morality-grounding metaphysically necessary entity in explaining morality’s metaphysical necessity over multiple contingent entities explaining it? Which one is simpler might be a bit unclear. Third and I think most problematically, the multiple contingent entity hypothesis is explanatorily inadequate and ultimately less simple than single-metaphysically-necessary-entity explanation of morality’s metaphysical necessity.

Why is that true? For one thing, any contingent entity can fail to exist, so the fact (if it is so) that there is some morality-grounding contingent entity in every possible world grounding morality cries out for explanation if we’re to satisfactorily account for morality’s metaphysical necessity. So how to explain why there is some contingent entity grounding morality in every possible world? Three options present themselves:
  1. In every possible world there is some contingent entity X ensuring that some morality-grounding entity G exists. But this simply pushes the problem back a step; what ensures that there is such a contingent entity X in every possible world?
  2. There is no explanation; it just happens to be the case that there is a contingent entity G in every possible world grounding morality. But since the number of possible worlds is quite literally infinite, it seems extraordinarily improbable that there just happens to be a contingent entity G in every possible world.
  3. There is something metaphysically necessary that ensures there is a contingent entity grounding morality.
So three options are (1) explanation via some other contingent thing; (2) no explanation; (3) explanation by reference to something metaphysically necessary.

Option (1) pushes the question back a step and so is explanatorily inadequate in ultimately explaining why a contingent morality-grounding entity is present in every possible world. If there is some contingent entity X to ensure there is a morality-grounding entity G, then to really explain why morality exists in every possible world we’d need an explanation for why there is some X in every possible world. If we are to avoid a vicious infinite regress we need to stop sticking with option (1) somewhere down the line. So even if option (1) were viable in explaining morality’s metaphysical necessity, to avoid an infinite regress we’d need something like option (2) or option (3) for contingent entity X (or at least to end any series of contingent entities responsible for entity X). Yet option (2) and (3) each have trouble.

Option (2) at least gives us a stopping point, saying that ultimately there is no explanation, but given the infinite multitude of possible worlds, the likelihood of this explanation seems infinitesimally small. Moreover, there is “the argument from subtraction” that suggests there are possible worlds with no contingent entities. There are surely possible worlds with fewer contingent entities than those that exist right now. And upon reflection it seems there is a possible world where only a thousand contingent things exist, and it seems there is a possible world where only fifty contingent things exist etc. all the way down to zero contingent things existing (at least if there is nothing non-contingent to ensure that some contingent thing exist). But if there are possible worlds with zero contingent things existing, then no set of contingent things can provide an ontological explanation for morality’s metaphysical necessity.

Option (3) is the best one, positing something non-contingent to ensure there is some contingent morality-grounding thing. But Ockham’s razor suggests we prefer fewer explanatory entities ceteris paribus, and so it’s better to posit just one metaphysically necessary entity to ground morality rather than a combination of contingent and metaphysically necessary entities.


At least when amended, I think the objection raises a substantive point. Arguably, metaphysically necessary entities are so unfamiliar with what we experience that it’s simpler to posit multiple contingent entities than a single metaphysically necessary entity when the multiple contingent hypothesis is adequate.

But ultimately I do not think the multiple contingent entity hypothesis is explanatorily adequate (particularly in regards to explaining morality’s metaphysical necessity) or simpler. It’s explanatorily inadequate in part because (1) it seems like there is a possible world with no contingent entities, in which case it would be false that in every possible world there is a morality-grounding contingent entity; (2) even ignoring (1), we’d need some explanation for why there happen to be morality-grounding contingent entities in every possible world, and appeals to “there is no explanation” and “the explanation is another contingent entity” don’t quite work. The multiple contingent entity hypothesis is less simple because to ultimately make it work—if we were to ignore problem (1)—we’d need an appeal to a metaphysically necessary entity, and it’s simpler to cut out the contingent entity middlemen and just posit the metaphysically necessary grounding entity.

Part of the explananda in an ontological explanation for objective morality is morality’s metaphysical necessity, and the best explanation for this seems to be a metaphysically necessary entity grounding morality.


  1. Hello, I just formulated an ontological challenge to materialism and I would love to learn your thoughts on that.

    Until now I only had comments from materialists.

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