Naturalism and Indefeasibly Decisive Moral Reasons: A response to Flannagan, Craig, and Layman, and a defense of Wielenberg

Previously I had developed an argument to the effect that, because stronger prudential reasons can always clash with moral reasons, morality and prudence are relative to each other. [1] I suggested this relativity might manifest in either direction: maybe some karmic force ensures that it is always prudent to be moral, or maybe morality is fundamentally egoistic so that it is always moral to be prudent. Both horns of this dilemma seem implausible, and so I took this to be a problem for the moral realist. My intention for this argument was, in fact, to knock it down, for I think I have come up with an attractive theory of moral obligation that invalidates it. I was wanting to show that my theory was worthwhile, and that by constructing it I had answered an important and difficult metaethical problem.

I was excited, then, to come across Matthew Flannagan critiquing Erik Wielenberg's atheistic moral realism on exactly these grounds, and rallying behind other philosophers in the process. [2] Flannagan quotes William Lane Craig saying, “if God does not exist, then prudential reason and moral reason can and often do come into conflict, in which case there is no reason to act morally rather than in one’s self-interest.” [3] He also cites Layman arguing that God must exist because, if there was no God and no afterlife, then prudential reasons could on occasion override moral reasons, leaving us without decisive reason to do our moral duty. [4] To this Craig says, “I agree with Layman that on atheism, what he calls the overriding thesis (namely that moral value always trumps prudential value) is not true, for one can have extremely strong prudential reasons for not acting morally, and there seems to be no common scale in which to weigh moral against prudential considerations”. [5]

Essentially, I had been defending Flannagan’s criticism of Wielenberg: that atheism and robust moral realism do not quite fit together. It seems implausible, given atheism, that there would be any karmic force ensuring that it's always prudent to be moral. And robust moral realism does not seem compatible with egoism.

Wielenberg's responses don’t quite hit their mark, and so it seems he has been pinned down. It looks as if that atheists and naturalists cannot accommodate robust moral realism. But these first appearances are illusory. As I had mentioned, there is an error in this argument being brought against Wielenberg. True, it may always be possible to have even stronger prudential reasons that clash with ones moral reasons. But that does not, in of itself, entail that those weaker moral reasons can always be defeated. They might be helped along by further normative reasons that defeat those threatening defeaters, and this is exactly what my theory is intended to explain. In the end, I will identify moral obligations with a kind of composite normative state of affairs that amount to indefeasibly decisive moral reasons. This will then explain why we should always be moral. It falls out of the very nature of a moral obligation, on my view, that you necessarily should do whatever is morally obligatory.

The overlooked mistake is that rebutting defeaters are not the only sort of defeater. There are also undercutting defeaters, which are more commonly spoken of in the context of epistemology. Where a rebutting epistemic defeater might be a strong bit of counter-evidence, an undercutting defeater would be one that takes a piece of evidence out of the equation. You might show that an argument is invalid, or that an experiment is flawed, or that a method used is unreliable. In doing so, you are not providing an epistemic reason that clashes with the original evidence. Rather, you’re providing an epistemic reason to not be motivated by it, or to not hold any belief on the basis of it. This is exactly the sort of defeater that arguments for extreme skepticism seek to defend.

There are clear examples of undercutting defeaters for practical reasons as well. Suppose you want to eat junk food, but you also want to not want to eat junk food. You want to no longer be motivated by your desire for junk food. Again, we’re not seeing two reasons clashing. Rather, we’re seeing one reason undercut the other. Your wanting to not be motivated by that desire only gives you reason to not be motivated by that desire, and not reason to abstain from eating junk food altogether. This can be clearly seen by supposing you had a second, different reason to eat junk food. Maybe, for example, you’ve developed an anxiety disorder over your diet, and your therapist thinks it would be beneficial for you to start eating junk food every once in a while. Your wanting to not be motivated by your desire to eat junk food gives you no reason to not be motivated by your therapists wisdom or your waning mental health. Talk of higher order normative reasons may be clunky, but it’s not outside of ordinary normative discourse.

For a case in the moral domain suppose you’ve been caught doing something wrong and, wanting to avoid punishment, you decide to lie to get out of trouble. Generally, wanting to avoid punishment is not a good reason to lie. In fact it seems like a pretty bad reason, especially when you deserve that punishment. Often times when people talk about “good” or “bad” reasons they really mean “valid” or “invalid”, and it’s easy to see that the latter meaning could be intended here. But in this case the reason seems both morally bad as well as invalid. In fact, we might think it’s invalid precisely because it’s morally bad. That is, the moral badness of lying to get out of trouble gives you reason to not lie to get out of trouble. You thus have a moral reason that undercuts your prudential reason to lie.

There are many other reasons to lie that might not be all that bad: to avoid hurting someone’s feelings, to make someone believe in a benign fantasy, to preserve a surprise that will bring them happiness, to confound a wrongdoer and protect his victims, and so on. Of course each is controversial to some extent. Many people don’t think it’s right to tell children that Santa Claus exists, while others think it’s harmless fun. And Kant was infamous for saying that you should never lie, not even to protect people's lives. This controversy can easily be seen as being over whether or not these are morally good or bad reasons to lie. Those who think that lying is categorically wrong will no doubt think that there are no reasons to lie that are not morally bad reasons. So the moral value of the motivating reason factors into a good explanation of why the motivated act is wrong.

It is worth noting that when looking for an example of something that is categorically wrong, people often describe actions in such a way that encapsulates the motivating reason. To use an extreme example, it’s always wrong to kill people for the fun of it. But, uncontroversially, it’s not always wrong to kill people out of self defense. Again the difference here can be seen as a difference in the sort of defeaters potentially at play. A person's life is intrinsically valuable, and so there is always moral reason to not kill people. But, wanting to defend yourself from an attacker doesn’t seem to be a morally bad reason to kill. And so this prudential reason remains undefeated, and clashes with and defeats your moral reason to not kill. In this case, then, we do not have decisive reason to abstain from killing. On the other hand, mere entertainment is certainly a morally bad reason to kill someone. Nothing could be more obvious. And so there is moral reason that undercuts this prudential reason to kill, leaving only the original moral reason to abstain from killing. In such a case, then, we do have decisive reason to abstain from killing.

But what about higher order prudential reasons? Couldn’t someone always have a higher order desire, that would defeat higher order moral reasons? What if, for example, someone wanted to do evil for its own sake? We should keep in mind how extraordinary this is. The vast majority of people are at worst apathetic to morality. It would take a real monster to be motivated by evil itself. Because this case is so unusual, I don’t think it would be biting much of a bullet to admit of a loophole here. That being said an answer can be given anyway. Surely wanting to do evil for its own sake is itself evil. That’s a pretty bad desire to have, and a bad reason to be motivated by. Even in these sorts of unusual cases, surely there would always still be further higher order moral reasons to not be motivated in this way.

We are now seeing what I had promised: a sort of composite normative state of affairs that amounts to an indefeasibly decisive moral reason to act. For an action to be morally wrong, or morally obligatory that we not do it, is for it to be both morally bad (so that there is defeasible, indecisive reason to not do it) and motivated by a morally bad reason (so that the reason to do it has been undercut).

The property of wrongness, then, is actually a property of action and motive pairings. It’s wrong to do something for some reason. There are two questions that naturally arise. Aren’t some actions categorically wrong, regardless of what motivates them? It does seem so, and in such cases any motivating reason would be a morally bad reason. So this is something my view can easily accommodate. But what if an action has no motivating reason at all? Well, if an action is wholly unmotivated then it’s like a hiccup or a sneeze. It’s either random, or caused by some involuntary process within the person. Such actions are hardly the sort of thing that we can be held responsible for, anyway. A prerequisite for doing wrong is being in control. If someone is acting truly without motive or reason, then it’s hard to see in what sense they are in control of that action. If they are able to prevent it, like we can hold back a sneeze, then their failing to do so may be wrong. But involuntary actions themselves, however morally bad, are never morally wrong.

On a second glance this theory is not all that novel. Condition (b) could be rephrased to say that the action is unjustified. For an action to be justified, it seems, is for it to have been motivated by some reason that is morally good or, at least, not bad. Indeed, this seems to just be what people ordinarily mean by “justified” in a moral context. So really my theory can be stated as: for an action to be morally wrong is for it to be morally bad and morally unjustified. This again seems rather analytic. I expect this just is the content of our ordinary concept of moral wrongness. I am not under any illusion, then, that my theory is especially insightful from the top looking down. What is interesting is the normative consequences I have drawn out from an action being both morally bad and morally unjustified.

One might be satisfied with this, but now turn their attention to moral value. How might the atheist or naturalist then explain moral goodness and badness? This is where Wielenberg’s view shines. Moral goodness and badness may be irreducible, objective properties, that give us normative reasons to act in certain ways. If this is correct then the metaphysical explanation stops here. This, then, is a sketch of how atheists or naturalists might hold to robust moral realism.


[1] http://www.metaethical.com/2018/02/answering-why-should-i-be-moral.html
[2] http://www.mandm.org.nz/2017/03/erik-wielenberg-and-the-autonomy-thesis-part-two-standard-objections-to-the-autonomy-thesis-reasons-to-be-moral-without-god.html
[3] William Lane Craig  “Q&A 230 Is Life Absurd without God?” available at http://www.reasonablefaith.org/is-life-absurd-without-god
[4] C. Stephen Layman “God and the moral order”, Faith and Philosophy, 19: 3 (2002) 304-16.
[5] William Lane Craig “This Most Gruesome of Guests” 183

An objective sort of moral subjectivism

By moral subjectivism I mean the view that moral properties are wholly comprised of subjective properties. That is, properties such as being valued, being regretted or being something that one would regret, being believed to be right, being taboo or prohibited by society, and so on. Subjective properties are those that relate to people's attitudes.

The most obvious reason to reject moral subjectivism is that moral properties do not seem to supervene on or be determined by subjective properties. It doesn't seem that people can always make a difference to which moral properties are instantiated by simply having different attitudes. Nor does it seem that a difference in the moral properties always requires there being a difference in people's attitudes. This sort of relativistic subjectivism seems clearly false.

For the most part subjectivism and relativism go hand in hand. But, in fact, we can tease out sort of subjectivism that doesn't render morality relative to people's attitudes in the way that I have rejected above. How can this be? In short, by adopting a non-reductive subjectivism wherein moral properties are wholly comprised of subjective properties, but do not reduce to subjective properties.

To see how this might be let's first take a look at the ontology of species. We might ask, what is it to be a tiger? We cannot give a definite answer in terms of non-contingent, necessary and sufficient conditions. If we could then that would raise an evolutionary paradox. Such conditions would either apply or not apply to any animal in a tigers ancestral lineage. But we know that if you trace back the lineage of a tiger far enough, you'll eventually get an animal that is not itself a tiger. And so it follows that there must have been a first tiger, born from a non-tiger. But that's just not how speciation works. We know that new species do not come about in a single generation. The property of being a tiger, then, must be potentially vague or indefinite in its instantiation. Once upon a time there would have been populations of animals that were not tigers which, over many generations, slowly evolved into populations that were tigers. And during this transition, there would have been animals that were neither definitely tigers nor definitely not tigers.

One way to make sense of this is to identify the property of being a tiger with a cluster of properties. That is, properties that are statistically grouped together, so that the presence of some make the presence of others all the more likely. Such clusters might have outliers and anomalies, and that doesn't seem to be incompatible with their reality. And so if we identify the property of being a tiger with a property cluster, then this avoids the evolutionary paradox.

Some things are clustered only by our grouping them together and labeling them with the same name. Such distinctions are drawn simply because it's useful to individuals or society, and not because that's how nature is genuinely carved up. But if that were the case here, then whether or not something was a tiger would depend on whether or not we labelled it a tiger. If all of society singled out a particular tiger, and decided that it was no longer a member of that species, surely society would be in error. Whether or not an animal is a tiger doesn't depend on whether or not it has been labeled as such.

More plausibly, it seems, tigers are grouped together by nature itself. There are naturally occurring causal mechanisms—i.e. the psychological, physiological, and genetic processes of tiger reproduction—that are responsible for the clustering of tigeresque traits in tigers. Human society is not required for any of this, nor does it add anything to it other than giving it a name. And, since it is a naturally occurring property cluster, it's surely real and objective in any meaningful sense. It is a way in which nature is genuinely carved up, albeit one with potentially vague boundaries. And it is this naturally occurring property cluster, then, that we have named "tiger".

Of course, there may be naturally occurring property clusters that we have not yet named. For instance, what about the naturally occurring cluster of human values? There are certain things for which it is just in human nature to value, usually manifesting as pro-social attitudes. Almost everyone wants to be thought of as being kind and generous and brave, even if they don't generally behave in such a way. No one wants to think of themselves as a villain. People will do mental gymnastics to excuse their bad behavior, so they can preserve some semblance of a virtuous self-image. This illuminates what we naturally value. And it's not difficult to see why this would be. Evolutionary pressures have made our species into social animals, that flourish when we live together and can depend on each other. So there are clear causal mechanisms in place that are responsible for human values being clustered about pro-social patterns of behaviour. Let's call this naturally occurring property cluster the human value cluster.

The human value cluster is wholly comprised of human values, just as tigers are wholly comprised of their tigeresque traits. There is nothing that any particular tiger consists of over and above its tigeresque morphology and genome and so on. That is to say, the biological characteristics of any particular tiger are, alone, sufficient for being a tiger. Likewise, then, there is nothing that any particular instance of the human value cluster consists of, over and above the evaluative attitudes that make it up.

Nevertheless, the human value cluster is, in a way, independent of the actual values that make up its instances. Even if society were to change suddenly, and people started valuing the opposite of what they do now, so that it was socially acceptable to be violent and malicious, and taboo to be kind and generous, even then this would not make a difference to whether or not it's natural for humans to have these attitudes. And so if we identified moral properties, such a goodness, with the human value cluster, this would result in a form of subjectivism that is nevertheless robustly non-relativistic.

But one might think that this isn't good enough. What if human evolution had gone otherwise, and it was instead natural for humans to value what we currently condemn? Doesn't this form of subjectivism entail that, if we were to naturally value malice, then malice would be good? It does not. Let's raise a similar question about tigers. Suppose some animal drastically different from present day tigers had evolved from the tigers ancestor. Would that animal then be a tiger, and would tigers then be drastically different from what they are today? It seems clear that they would not. If evolutionary history had gone otherwise, tigers just wouldn't exist. Some different animal would exist instead. Similarly, then, if human evolution had gone quite differently, so that humans naturally valued the complete opposite of what they do now, then the human value cluster simply wouldn't have existed. Some other cluster of human values would have taken it's place. And that other cluster is not what we have named "the human value cluster". What follows, then, is that there wouldn't have been such a thing as goodness at all.

This "objective" sort of moral subjectivism renders moral properties robustly non-relativistic in their instantiation, but not in their reality. This should be seen as something of a win, for the latter sort of relativism is not nearly so deeply unintuitive as the former. That being said, I don't doubt that there are problems with this latter sort of relativity as well. But many views, if not all, face problems, and one might think that this is not significantly worse than competing theories of moral ontology. This may very well be a viable form of moral subjectivism.

Exploring the "why be moral?" question

Why should we be moral?

At face value this is a trivial question. It just is, in part, what we mean by the word "moral" that we should be moral. Our concepts of morality, good and evil, right and wrong, virtue and vice, and so on, are normative concepts. It is analytic that moral properties give us normative reason to behave in certain ways. And so this question is something like asking why all bachelors are unmarried men, or why all triangles have three sides.

And yet, this doesn't quite feel satisfying. The question may still seem to raise an important challenge for moral realists to answer. I think this is only because of commonly held, unspoken assumptions that one has in their mind when considering the question. These assumptions make it difficult to say that we should always be moral. And so, when paired with what has been said above, these assumptions form a challenge to the moral realist. They might go something like this:

1. We should do whatever we have most reason to do
2. But if someone were to want to do something enough then they would have most reason to do it
3. Therefore, if someone were want to do something enough then they should do it

The first premise seems almost analytic itself. Normative reasons weigh for or against certain responses of agents. Often times different reasons aggregate to form an even stronger reason, or clash and cancel each other out. This is most clearly seen in the case of epistemic reasons, where each piece of evidence provides a unique reason to affirm or deny a theory. Whether or not we should believe the theory depends on how these individual reasons weigh up. The word "should", I take it, just refers to this sort of aggregate normative reason that weighs decisively in favour of some response.

But the conclusion (3) is in serious tension with a robust, non-relativistic form of moral realism. The robust realist would want to say that,

4. If something is immoral, then it would still be immoral (and would still be something we should not do) no matter how much we wanted to do it

From this and (3) it follows that,

5. Therefore, nothing is immoral

This, I think, is what motivates the question at hand. That, because of (1) and (2), we are trapped between moral relativism on one hand, and moral nihilism on the other. The question might be seen as a rhetorical move to prompt this realization. That second premise, then, will be a point of controversy. Many find (2) intuitive, but at the same time find (4) and (5) to be very unintuitive. So why not respond with a Moorean shift? A better defense of (2) is needed, and I think a compelling one can be given as follows.

2.1. There is no limit to how much someone can want to do something
2.2. Therefore, there is no limit to how much prudential reason someone can have to do something
2.3. But there is a limit to how much moral reason there is to do something
2.4. Therefore, if we want to do something enough (so that there is more prudential reason to do it than there is moral reason to not do it), then we will have most reason to do it

Premise (2.1) and the inference from it to (2.2) seems plausible. That someone wants to do something no doubt gives them prudential reason to do it, and the weight of the reason would be proportional to the strength of their desire.

Some might think to reject (2.3), but I am skeptical of this move. Moral reasons supervene on biological, psychological and sociological factors, such as health and happiness, fairness, liberty, and equality. Just as the weight of prudential reasons are proportional to the strength of ones desires, the weight of moral reasons seem proportional to the extent to which these subvening natural factors are being promoted or discouraged. At the same time, moral reasons appear to contribute only finite weight for or against some response. After all, things could always be worse. Murder is worse than theft, though both are immoral. But comparisons of this sort are meaningless between infinite magnitudes. Since such comparisons are sensible, and since the subvening natural factors are finite, it seems moral reasons must contribute only finite weight.

Others may think to resist the inference from (2.2) and (2.3) to (2.4), and suggest that at least some moral reasons just cannot be defeated by prudential reasons—no matter their relative strength. But this is rather odd, and demands explanation.

A more sensible answer is to just admit that morality is relative to prudence. But that relativism needn't go in any one direction. Many believe that God will punish all wrongdoers and reward the righteous in the afterlife. Similarly, some will argue that there are certain interests all humans have, in virtue of being rational agents or social animals, that are most effectively realized by being moral. If this is true, then we have decisive prudential reason to live a moral life and abstain from immorality. One can thus explain how it is that we should life a moral life, without even mentioning moral reasons. In this way, then, one can accommodate the relativity of morality and prudence without committing to a radical and unpalatable form of moral relativism.

Many find this compelling, but I am dubious. Relativism in either direction, morality being dependent on prudence or prudence being dependent on morality, doesn't strike me as correct. There are still counterfactuals that require explanation, such as: "Even if it were imprudent to be moral, we should still be moral." There is still a sense in which morality is non-relativistic, that these sorts of answers don't seem to be able to explain or accommodate.

An Interaction Problem for Dualism of the Mind

Our minds and bodies causally interact: our beliefs and intentions cause our bodies to behave in certain ways, and the sensory organs of our bodies cause us to have qualitative experiences and to form beliefs and so on. Let's grant that we can make sense of causation between fundamentally different properties and objects.

But how do we make sense of the fact that my mental states are only ever caused by my bodily states, and vice versa? Why is it that I only ever see the world through my eyes, and only ever behave in accordance with my beliefs and intentions?

On physicalism we can say that someone's mind causally interacts with only their body because their mental states reduce to or are constituted of their brain states, and only that persons brain states can interact with their bodily states.

But on dualism there seems to be no explanation.

Therefore, physicalism bests explains the interaction between minds and bodies.

The Problems of Evil and Poor Design

I think the problem of evil can be made most forcefully when amalgamated with an argument from poor design. This is essentially the move Paul Draper makes with his Bayesian argument from evil. Draper notes that pain and pleasure serve a biological role that makes sense on a hypothesis of indifference (and is arguably a prediction of evolutionary naturalism), but is incredibly surprising under the hypothesis of a morally conscious creator.

The idea is that some features of the human design are morally significant, so that a morally concerned designer would have reason to discard or, at least, revise such design. But on naturalism, the forces of evolution are indifferent to the moral significance of the design it produces.

For another example consider how, compared to most other animals, giving birth is incredibly difficult and even dangerous for humans. On evolutionary naturalism the explanation is obvious: there were very powerful evolutionary pressures on our ancestors to have narrow hips to facilitate our bipedal mobility, and very powerful evolutionary pressures for humans to have big heads to facilitate our big brains and great intelligence. But both these traits together obviously mean a lot of trouble for birth. A morally conscious designer would see that this will cause a lot of unnecessary death and suffering and design things differently, but evolution is blind to these things as long as they don't impede reproductive fitness.

We then have two competing hypotheses: an anthropic origin by evolutionary naturalism, or by a morally conscious creator. And since each entails the negation of the other, we have strong reason to think there is no morally conscious creator.

A Moral Argument Against Theism

It's commonly thought by theists that, in the absence of God, one is faced with difficult ethical or meta-ethical problems. Within the atheistic world view, morality itself, moral knowledge, moral motivation and so on are thought to be on shaky ground. Such beliefs are the basis of moral arguments for theism. Here then is a similar argument in the reverse: the existence of God, along with three indubitable and commonly held ethical beliefs, leads to a vexing contradiction.

1. It is wrong to treat people as a means to an end, rather than as an end in of themselves.
2. God (a perfect being who can do no wrong) allows innocent children to suffer and die for some greater end.
3. Therefore, that greater end must be greater for the child: it must be in his own best interests to suffer and die.
4. We should always aim to do what is in the best interests of others, and avoid doing what isn't in others best interests.
5.  Therefore, we should not attempt to prevent the unbearable suffering or untimely death of innocent children.

But of all things, the unbearable suffering and untimely death of children seems to be something we should always aim to prevent. To deny this is absurd, so one of the premises must be rejected. Premise (1) is a statement of Kantian ethics, a very popular normative ethical theory. It seems too obviously true to reject. Premise (2) is true if God exists at all. To reject this would be to reject theism. Premise (4) seems to follow from our very a priori concept of a moral should. These are the only three premises.

What makes this argument interesting is that (1), (4) and ~(5) are almost impossible to reject. If anything could be taken as self-evident, surely these statements should be. God's existence, on the other hand, is not self-evident. Even if theism is very well evidenced, it's surely not as well supported by our intuition as these three other statements. Therefore, we must reject theism in favour of these three induibiable ethical statements.

Divine Nature Theory and the Parsimony Problem

Divine nature theorists believe that goodness is grounded in a likeness to God's essential nature. As they would say, it is good to be loving and kind and just because God is loving and kind and just. In other words, the property goodness reduces to being a member of the set of properties that God holds necessarily. But one might wonder, why do we need God at all? Wouldn't it be simpler to say that goodness reduces directly to that collection of properties, without referencing God's nature? Why shouldn't we rather say that what it is to be good is just to be loving or to be kind or to be just and so on? This revised theory would seem to have all the same explanatory power as divine nature theory, but would be a great deal more parsimonious for not requiring the existence of God.

I once suggested this to a friend, and he responded by saying that in such a case there would be nothing all good things had in common. But this seems odd: surely for there to be such a thing as goodness, there must be something all good things have in common. Intuitively, he thought, there must be something that brings all these properties together (and in the darkness binds them). At the time I was unaware of the classic counter examples: species being an obvious case of a bundle property, being made up of a collection of properties which do not necessarily all share something in common. There are no necessary and sufficient conditions for being, for example, a lion. By analogy, we might think there need not be necessary and sufficient conditions for being good.

On top of this I now think there are two even stronger objections to this line of reasoning:

First of all, divine nature theory itself suffers from the same problem my friend had with treating goodness as a bundle property. Why is this? Because being like God is a bundle property. There is nothing all of God's essential attributes have in common, other than being those attributes God necessarily instantiates. The only difference is that we've given this collection a name ("God's essential nature") and ground goodness in a likeness to it. Theists may suggest that on greatest being theology, the divine nature theorist could think that all God's essential attributes have in common their being great-making. But greatness is no less metaphysically queer and demanding of explanation than goodness, so this move would only push the need for grounding a step back without really explaining anything substantial.

Secondly, there is something all good things have in common without God after all: their normativity. If something is good, then there is reason to conduct oneself towards it certain ways. There is reason to desire good things, to perform good actions, and to praise the good behavior of others. Furthermore, most would say this follows from our very concept of goodness itself. We therefore need not talk about God's essential nature to explain what it is to be good.

Divine Nature Theory: Why goodness is not a likeness to God

Divine nature theory is what I call the common theistic meta-ethical opinion that goodness is grounded in a likeness to God's essential nature. God is essentially loving and kind and just, which is taken to explain why it is good to be loving and kind and just and so on.

But there is an obvious counter example to the theory as so far construed: God has many essential characteristics that are not morally significant. God is essentially immutable, necessarily existing and ontologically self-sufficient. But it would be absurd to say that something was good in virtue of its being immutable, necessary or having aseity.

The divine nature theorist might try to revise his view, saying instead that a thing is good just in case it bears some resemblance to God's essential behavioral qualities. Necessity, immutability and aseity have nothing to do with behavior, and so they pose no threat to this view. And yet, other counter examples can still be raised. God is essentially rational, prudential, decisive, and is essentially not impulsive or whimsical. But it seems silly to think that being irrational or imprudent would have any affect on the moral value of ones action.

The divine nature theorist might take a further step back, saying instead that a thing is good just in case it bears some resemblance to God's interpersonal behavioral qualities. Being rational doesn't have anything to do with how one treats others, but lovingness and kindness and justice does.

But now there's an even more pressing problem, in that these qualities don't seem like essential characteristics of God. God cannot be necessarily loving or just, since there are no other necessarily existing people to be loving or just towards. Some have suggested positing the trinity to solve this very problem, saying God's persons necessarily love each other. But love is just one of many morally significant properties the theist is trying to ground in divine essence. What about other morally significant behavioral qualities, like being someone who punishes the wicked, or who protects the defenseless? There are no necessarily existing wicked or defenseless people for God to stand in the appropriate interpersonal relationships with.

The divine nature theorist might try one last revision. He might suggest that goodness is grounded not in any qualities God actually has, but in counterfactuals about what God would do given the opportunity. And so protecting the defenseless is good because, given the opportunity, God would always protect the defenseless.

But now the divine nature theorist has made God entirely dispensable to his theory. Even atheists can believe that, if God were given the opportunity, then he would protect the defenseless. Divine nature theory, then, reduces to something very much like ideal observer theory, and is no longer an inherently theistic account of goodness.

Possibility of the Actually Infinite

Mathematicians define two sets as being the same size whenever there is a bijective mapping from one to the other. That is to say, whenever each member of the one set can be paired up with exactly one member of the other. At face value this makes perfect sense. If you're at a dinner party and every guest has brought a significant other of the opposite sex, then clearly there are just as many men at this party as there are women.

Why does this matter? Because, if same size is understood as mathematicians define it, then it easily follows that a set can be the same size as its proper subset. In other words, the common objection to the possibility of actual infinities simply fails by definition.

It's all the more clearer with an example. The natural numbers {1, 2, 3, ... } and the even numbers {2, 4, 6, ... } are the same size because a bijective mapping exists between them: f(x) = 2x, which pairs 1 with 2, and pairs 2 with 4, and 3 with 6 and so on. And, of course, the even numbers are a proper subset of the natural numbers.

Now you might think, this sounds super abstract. Maybe this is some weird technical idea that mathematicians throw around, but surely all this mathematical mumbo jumbo isn't anything like my understanding of what it means for two sets to be the same size. But actually, it is.

When someone wants to know how big a set is, they count the members. They point to an object and say "one", they point at another and say "two", and so on. They don't know it, but they're proving the existence of a bijective mapping between the set in question and the subset of the naturals they're vocally describing. And because the size of the set they're counting out is identical to the value of the last member, they (all by intuition and not understanding the math) infer the size of the set in question. It's odd to think that something so simple as counting has a rigorous mathematical basis that utilizes the mathematicians very technical definition of same size, but it in fact does.

Of course we needn't proceed one member at a time when counting. We could just as well point to a pair and say "two", and another pair and say "four", and so on. Or we could go by groups of ten, or hundreds or, even, the collection as a whole. It follows from this that, contrary to popular opinion, we can count an infinite set after all, we just do it all at once instead of step by step.

Here's the catch, then. People who think that actual infinities are impossible (almost always because they think it's impossible for a set to be the same size as its proper subset) owe the rest of us an explanation of what 'same size' means, if not what mathematicians mean. Since they are unable to give any answer, their objections to actual infinities (usually to the possibility of an eternal past) fall flat.

Evil as an Absence of Good?

It's very common for people to think that evil doesn't actually exist in of itself. Rather, like a hole in your shirt is just an absence of fabric, some would say evil is just an absence of good. Of course that doesn't mean there is no truth about evil, or that it wont affect your life. A large hole in your jacket, despite not being a thing in of itself, will still make you miserable on a cold, wet winters day.

But there is an obvious problem with this view, in that it would require all things (at least within the relevant domain) to be either good or evil. You can't have shirts that are neither whole nor have a hole, but you can have actions that are neither good nor evil—in fact most actions seem morally insignificant. What could be the moral value in cutting your grass, or eating a cheese burger? If you find some morally significant feature, one can always easily stipulate a scenario in which that feature isn't present.

And so defenders of this view must embrace the implausible and maintain that every action, no matter how seemingly insignificant, has moral value to some degree. This is why I favour theories of moral ontology on which good and evil are both real in a robust sense, neither being an absence of the other.

Skeptical Theism and Divine Deception 2

I have become convinced that my argument outlined in Skeptical Theism and Divine Deception is not successful.

The problem is that I failed to distinguish between having justified belief, and being able to justify ones belief. The difference is that we can have justified belief without being aware of it. On externalism, the justification for a belief can be something that the subject might not even have access to, like the causal history that produced his belief. But justifying ones belief is an action rational people perform, a sort of giving of an explanation or an account of how one is justified in holding that belief.

It follows from externalism that, for all I know, the skeptical theist might be justified in believing God always tells the truth—my premise (3) is indefensible. And yet the spirit of my argument persists. If you think about the role divine revelation plays, it's always intended to account for the justification of religious belief. Religious folk would say "God has told us these things and therefore they are true," implicitly assuming that God is not lying.

But now it's clear that the implicit assumption is not plausible so long as we're committed to skeptical theism. After all, for all the skeptical theist knows, God could have a morally sufficient reason to lie about religious matters. (See the previous post for a more in depth analysis of this).

So while the skeptical theists' religious commitments might be justified, they are not something he can justify. And, since we should exercise a healthy skepticism about beliefs we cannot ourselves justify, there is still tension between skeptical theism and religious belief. It seems, at least, the skeptical theist should be no more confident about his religious beliefs than he thinks is appropriate for gratuitous evil.

We can re-formalize this argument as follows, where P is the sort of belief we can only justify by appealing to divine revelation (namely, religious belief):

1. Without appealing to divine revelation, there is no way to justify the belief that P
2. Skeptical theists cannot appeal to divine revelation to justify their beliefs
3. Therefore, skeptical theists cannot justify their belief that P
4. Doubt should be reserved for beliefs we cannot justify
5. Therefore, skeptical theists should reserve doubt for their belief that P

Kripke's Argument for Dualism

1. It's possible for there to be mental states without brain states
2. Therefore, mental states are not identical to brain states

Since mental states (e.g. pain) and brain states (e.g. c fiber stimulation) are ridged designators—referring to the same object in every possible world—the inference from (1) to (2) is valid. Kripke thinks, and I want to agree, that at face value premise (1) seems to be true. And so the materialist, wanting to say that mental states reduce to brain states, is faced with the challenge of explaining away this intuition.

The materialist might meet Kripke's challenge by rallying behind other well established identity claims, considering them partners in crime. If we're not prepared to entertain doubts about, for example, water being identical to H2O, or lightening being identical to the discharge of electrons, or heat being identical to the excitement of molecular particles, then why should we doubt that mental states are identical to brain states? While the materialists theory isn't nearly as well evidenced as these other identity claims, it's still the best explanation of why mental states are so perfectly correlated to brain states. But surely the intuition that minds could persist in the absence of brains is no stronger than the intuition that water could exist in the absence of H2O, or that lightening could occur without a discharge of electrons.

But Kripke has an answer to this. He suggests our intuitions about the possibility of there being water without H2O are misguided. It's plausible, he thinks, that we are mistaking the one possibility with another: that there is something that is phenomenologically identical to water (that we have no way, short of a chemical analysis, to distinguish it from the stuff that fills our rivers and lakes and oceans) when there isn't any H2O. But, as Kripke argues, such an explanation misses its mark when applied to the materialists reductionist theory of mind. There cannot be anything that is phenomenologically identical to pain, and yet isn't pain. If someone thinks they're in pain, or is having an experience of being in pain, then they are in fact in pain. Pain, in other words, cannot be illusory. And so the materialist cannot use these other well established identity claims as partners in crime: the evidence incriminates him alone.

Kripke thinks he's successful in defending, at the very least, a presumption against materialism. But I think there's a further response the materialist can give. Granted, it's intuitive that unembodied minds could exist. But it's no less intuitive that the materialists theory could be correct, and that mental states could actually be identical to brain states after all. But of course, if mental states are identical to brain states then they are necessarily so, and premise (1) of Kripke's argument must be false. We thus have two equally valid but opposing intuitions. What do we do with them? I suggest they cancel each other out, and leave us without any presumption either for or against materialism.

But then we are back to where we started, with no reason to reject a materialist theory of mind and some fairly significant reason to accept it: along with ontological parsimony, the identity of mental states and brain states offers an attractive explanation of the appearance of supervenience. It seems, then, that if anything at the end of the day we are left with a strong presumption in favour of a materialistic reductionism of the mind.

Problems with Agent Causation

What is causation? As I understand it, if X causes Y then:

1. X and Y are temporally indexed propositions (or some metaphysical analog to propositions; i.e. facts)
2. X is temporally prior (or maybe simultaneous) to Y
3. X counter-factually entails Y

These three conditions seem to be built into our very concept of causation, and while maybe they are not alone sufficient, they surely seem necessary.

But this conflicts with the agent causation brand of libertarian freewill, which requires that causation is the sort of relationship that can involve—as operands—particular objects. Say the effect in question is "Sam's choosing to eat breakfast", then if it's a free choice it must be caused by Sam himself. It cannot be caused by any events containing Sam, or any sort of fact about Sam (e.g. his being hungry), but must be the object that is Sam. In this case, how can we understand causation? We must give up not only (1), but also (3) since particular objects cannot stand in counter-factual entailment relationships, and (2) since it makes no sense to talk about objects themselves being temporally indexed. Events containing objects might happen in some temporal order, and propositions about objects might be true at particular times, but it doesn't make much sense to attribute temporal attributes to persons. And even if it did, still Sam existed prior to the event, he exists while the event takes place, and hopefully he will continue to exist afterwards. So regardless, (2) must be given up.

In other words, to accept this brand of libertarian freewill, we have to reject everything we intuitively understand to be causation. Can the libertarian say; fine, maybe Sam's choosing to eat breakfast wasn't caused? Of course not: how could Sam exercise control in any meaningful way over an uncaused event? Such an event would be random, and randomness precludes freewill.

The libertarian might offer non-personal examples of 'object causation' in his defense, like a ball breaking a window. But to me this only sounds like a case of sloppy language. Everyone implicitly recognizes that when we say "the ball broke the window", what we really mean is "the ball hitting the window broke the window". Obviously if the ball had not hit the window, the window would not have broke. But then "the ball hitting the window" is an event, and not a particular thing: the cause and effect are both events. This therefore isn't actually a good example of object causation, because once we clarify what needs to be clarified, it's pretty obvious that it's really an event and not an object that's causing the window to break.

With all this said, it's very unclear how those who accept this brand of libertarian freedom can make sense of 'causation' without it ruining their view.

Conceivability of the GCB

Some argue that conceiving of something isn't as foolproof as we might typically think. This is a common response to Chalmer's philosophical zombie argument. When you're conceiving of a philosophical zombie, how do you know you're not really just thinking about a conscious person? What is different about the two conceptions? Is it that, in the one case, you're saying in your mind 'this thing is not conscious'? But surely being able to simply describe something doesn't amount to conceiving of it: even machines can do that. Indeed, we can even describe inconsistent scenarios, but it's odd to say such things can be conceived of.

It's like trying to conceive of a transparent block of iron. Close your eyes, can you do it? Once you've managed to conjure up an image, ask yourself; how do I know this isn't really just a block of glass?

Now turning to theological matters: how do you know you're thinking of the greatest conceivable being? Is it simply because you're saying in your head, "this thing is greater than anything else I could conceive"? Indeed, how do you know it's not the second or third greatest, rather than the first? It seems Anselm's God is like the transparent iron, or the philosophical zombie: even if such a thing is conceivable, we don't have good reason to believe it.

Divine Hiddenness and Hitchens Worlds

It is often argued that the absence of decisive reason to believe in God is, in of itself, reason to disbelieve. This is known as the problem of divine hiddenness and, much like the problem of evil, identifies features of the world that are unexpected under the assumption of classical theism. One might note that, if God were to exist, he would want to cultivate a personal relationship with all of his creation. But many people, despite being open to theistic belief, find themselves unable to shrug off rational doubts. Because it's impossible to have a relationship with someone you don't even believe exists, these rational doubts stand as a inculpable roadblock for people entering into this loving relationship with God. Divine hiddenness offers a very different sort of challenge than the problem of evil, and incites theists to develop novel theodicies to explain why God would permit rational disbelief.

Some have supposed that, even if God made his existence apparent to all, it would only result in greater numbers of people who would reject him. Knowing God existed, people would beg him to save them from evil. But God would not do away with those evils anymore than he does now, and this would plausibly make people bitter against him. People like the late Christopher Hitchens, not simply being atheist but being anti-theist, might become the norm. Instead of simply not believing in God, they would hate God and actively resist him. Such is a Hitchens world, one in which a large portion of creation hates their creator and actively resists a relationship with him all the while accepting his existence.

Supposedly God can work around non-belief. If one does away with any idea of a hellish afterlife for non-believers, they can reasonably think God doesn't simply give up on his creation at their death. Rather God would pursue his creation into eternity, so that eventually every person would have opportunity to love and be loved by him. But a Hitchens world would be dastardly for God's goal of bringing all of creation to himself. Plausibly, these powerful negative emotions towards God could do more damage and stand as a much bigger roadblock to a loving relationship with God than mere non-belief.

While this theodicy has an air of plausibility, there are a number of holes that would have to be filled before it could be called a success. First of all, it would be rather strange for God to give us decisive reason to believe his existence, but not his moral perfection. Indeed, on classical definitions of God, any decisive reason to believe his existence would necessitate decisive reason to believe his moral perfection. And so in a Hitchens world, everyone would be fully aware and in agreement that God is morally perfect, and that every evil he permits he does so for very good reason. But how could people then hate God? It would require them to be incredibly petty, or immature, or irrational.

God, being the creator of man, is supposedly directly responsible for human psychology. If we responded immaturely or irrationally to his justified permission of evil, then it could only be because he chose us to be that way. God could have just as easily created us to be more charitable and humble in our attitudes and judgements. It's not clear why God wouldn't simply have created us with different (and, in fact, more noble) psychological tendencies. In light of this, it's still very unexpected that he would hide his existence from creation.

Secondly, the real world is populated by a great many religious people who are wholly convinced of God's existence. And yet, hatred of God doesn't run rampant within theistic communities. In fact, if anything, it seems conviction in theistic belief has the complete opposite effect.

A Dilemma for Divine Command Theorists

I am expanding and hopefully improving on a previous argument against divine command theory, given here. According to divine command theory, the wrongness of an action is metaphysically identical to the actions being contrary to the commands of (a loving) God. My objection takes the form of a dilemma: Either God can issue commands to people knowing they will have rational doubts about its authenticity, or he cannot.

If he can, then we have a strong counter example to divine command theory. Surely having rational doubts about the authenticity of a command nullifies any obligation to obey it. For example, if you received a note from the government that lacked any official markings and appeared to be inauthentic, then you can't be expected to meet their demands. And if the government didn't even put any effort into presenting the command to you in such a way that you would recognize its authenticity, then it seems absurd to think you are under any obligation to do as they require of you. With this, it follows that it would be possible for God to issue commands without generating any obligation for the recipient to obey. And since facts about identity are non-contingent, divine command theory must be false.

If he cannot, then divine command theorists face a similar challenge that's almost as bad. For if God has issued someone a command, then as long as they are rational they will recognize that the command comes from God and not anyone else. But if a rational person is aware that God has issued them a command, then they are aware that God exists. And so, if a rational person has received a command from God (i.e. if they have a moral obligation), then they are aware that God exists. But there are many rational non-believers who do not believe and are not aware that God exists. And so there are an uncomfortably large number of people who must have never been issued any commands by God.

And so divine command theorists are impaled on either of the two horns of this dilemma: either they're confronted with a compelling counter-example to divine command theory, or they must admit there are a great many people for whom every action—no matter how monstrous—is morally permissible.

Divine Command Theory and the Obligations of Atheists

1. To issue a genuine command requires that you make an honest effort to make the recipient aware that you are the one commanding them (such that a rational person would recognize the authority and authenticity of this command).
    
2. God is omnipotent, and thus does everything he makes an honest effort to do.
    
3. Therefore, if God has issued someone a genuine command, then he must have made them aware the he is the one commanding them. [1&2]
    
4. But if a rational person is aware that God is commanding them, then they are aware that he exists.
    
5. Therefore, if a rational person is not aware that God exists, then they have not been issued any commands by God. [3&4]

And of course from (5) it follows that, on divine command theory, rational non-believers have no obligations and can do no wrong. But that's absurd: atheists have obligations just as much as anyone else, so there must be some flaw in the argument. Premise (2) and (4) seem indubitable, so it all comes down to rejecting (1) or rejecting divine command theory.

But premise (1) is very plausible. Imagine getting mailed a note from the government, written in pencil on loose leaf paper, without any official markings, and no name signed at the bottom saying, "you're summoned for jury duty, show up at the court house next Thursday morning". You would throw the paper away immediately, and it would seem rather silly to think you were the recipient of a genuine command, or that you had any obligation to obey. If the commander hasn't even tried to issue the command in such a way that a rational recipient would recognize its authenticity then, though the commanders will has been expressed, this expression doesn't seem to amount to a genuine command. But of course this is what scripture or religious tradition looks like to rational non-believers, and they will be very justified in doubting the authenticity of purportedly divine commands.

A Bayesian Response to External World Skepticism

The skeptical argument against the real world hypothesis (RWH) is this:

1. If I'm not justified in believing I'm not a brain in a vat, then I'm not justified in believing I have hands
2. I'm not justified in believing I'm not a brain in a vat
3. Therefore, I'm not justified in believing I have hands

Premise (1) follows from the undeniable closure of justification on known entailment. And so you might try objecting to premise (2) by saying you are in fact justified in rejecting the possibility of being a brain in a vat. You might say, look here I have hands! Here's one, and here's the other. I can feel them, I can touch them: is this not good enough reason to believe they are real? But, then again, if this all was an illusion and you were just a brain in a vat, what would you expect to be any different? Every experience of having hands just as well supports that you have hands, as it supports that you're a brain in a vat being tricked into thinking you have hands.

By the very construction of a skeptical hypothesis (SKH) it has the consequence that, for all possible experiences e, e is just as much expected on SKH as it is on RWH; Pr(e|SKH) = Pr(e|RWH). This is a plausibility rather than a probability judgement, in that the Pr function outputs the level of expectation or surprise we have (or should have) in the operands.

Baysians update their beliefs in accordance with Bayes theorem upon being presented with evidence. And so given that the two hypotheses are empirically equivalent, as long as the priors are also equal, it would be impossible for the Baysian to confirm RWH over SKH on evidential grounds. But now consider how the disparity between two hypotheses grows exponentially as evidence is accumulated, and how much evidence we really have (every experience of every moment of our lives). Even if two hypotheses are empirically equivalent, the same evidence could support one dramatically more than the other if the priors weren't equal. And, given that the two hypotheses are incompatible, we are then forced to reject SKH in favour of RWH. We can, then, happily say that we know SKH to be false. Notice that I am not simply Moore shifting. I am not saying I know SKH is false because I know RWH is true. In fact, even under the assumption that I don't have good enough reason to believe RWH, we still have good enough reason to reject SKH. The skeptical hypothesis is still defeated, even if the real world hypothesis cannot be established. And so, if we could justifiably say that Pr(RWH) is even a little bit greater than Pr(SKH), then we could have a solid answer to external world skepticism.

It all comes down, then, to establishing these priors. Traditionally Baysians address the priors of two competing hypotheses by simply ignoring them. They would say; set the priors to whatever you would like, and given the accumulation of enough evidence one hypothesis will eventually overwhelm the other. If we see a dramatic tendency for one hypothesis to be better evidenced than another, we can inductively infer that this pattern will continue and that future findings will continue to favour the one over the other.

But of course this strategy fails here, since the RWH and the SKH are empirically equivalent. You can gather as much evidence as you'd like, it will never favour one over the other as long as the priors are equal. The Baysian is then left with two options. On one hand he can arbitrarily set the prior probabilities to favour RWH, and in doing so give a rather unsatisfying answer to the skeptic. If all we can muster is an arbitrary rejection of skepticism, then it seems we have failed to offer a genuine response. On the other hand, the Baysian can seek out a priori principles to guide our judgement of priors. There is already one such principle at play, the principle of indifference: in the complete absence of probabilistic information, we should treat the priors as if they are equal. And it is exactly this, or at least something very much like it, that fortifies the skeptics argument.

Notice that this principle is cashed out in terms of what we should do, or what our expectations should be. But what sorts of principles could these be? It seems futile to come up with principles that track the objective probability of a hypothesis. So we should understand these principles as guiding our expectations. But then there is something inherently normative about these principles: they tell us about appropriate expectations to have. An epistemic realist (a term coined by analogy to moral realism) might say that there are simply normative facts governing how we should compare hypotheses. They might say that someone who accepts ad hoc explanations is doing something they simply shouldn't be doing. And it's not because ad hoc explanations are more likely to be false (indeed, it's unclear how such a claim might be defended), but simply that an explanations being ad hoc constitutes reason in of itself to reject it or, at least, be more suspicious of it.

Indeed there are probably many more intrinsically good or bad features for a hypothesis to have, like parsimony, explanitory fit, falsifiability, or even aesthetic appeal.

What we need are a priori principles by which we can favour one hypothesis over another. And this we have. It's naturally thought that parsimony and explanitory power are intrinsically good features for a hypothesis to have. And, being ad hoc or unnecessarily complicated are intrinsically bad features for a hypothesis to have.

God and Moral Grounding

According to the common theistic view of moral ontology, facts about moral value reduce to facts about what God is like. This is an a posteriori property identity claim, that the property x is good is literally identical to the property x is like God's essential nature. As such God is not just one good thing among many, but rather he is the very standard to which all good things measure up. He is, according to this view, what Plato called the Good. Rather than explaining evil, theists typically explain it away. The common analogy is that, just as darkness is the absence of light and cold is the absence of heat, evil is merely the absence of good; the absence of any likeness to God. Just like a hole in your shirt, evil technically doesn't exist. It's not a thing in of itself. Even yet, just as a hole in your shirt will leave you cold, evil can still negatively affect you. Having an absence of God or his likeness in your life will, as it's thought, lead you to ruin.

The motivation for this view is that it explains, or best explains, the nature of morality in such a way that preserves our common ethical opinions. Since God is necessarily loving and kind and just, we get, as a result, that it's good to be loving and kind and just. But there are other essential characteristics of God that don't seem to fit into this paradigm. For example, God is necessarily prudent in that he doesn't thwart his own goals, but rather acts efficaciously to bring about his divine will. God is necessarily rational, in that he doesn't accept or hold propositional attitudes that go against the dictates of reason. And God is necessarily immutable, in that he does not behave inconsistently or arbitrarily from one day to the other. It would be rather absurd to think someone is failing to live up to the moral standard by being irrational, or acting imprudently. There might be a sense in which someone who believes contradictions is doing something objectively wrong, but this isn't a moral wrong. Believing contradictions makes one guilty of foolishness or irrationality, but not of moral wrongdoing. So, it seems, this account of moral ontology must fail.

There are further problems with the attempted explanation of evil. If evil is merely an absence of good, then good and evil must partition all things. Something must either be good, or be in the absence of good; there isn't any third option. But of course this is absurd, the vast majority of actions we perform are neither morally good nor evil. Every choice would become a moral choice, and every action would be morally significant. So again, it seems this account of moral ontology must fail.

Defending Moral Naturalism

There's a trend among religious apologists to lament the supposed moral bankruptcy of non-theistic world views, saying that in the absence of God there is no way to account for moral ontology. And yet, these apologists seem to never actually engage with the ideas within contemporary metaethics. Indeed, they often seem entirely ignorant of what philosophers actually believe about moral reality, let alone why.

I seek to defend moral naturalism, a non-theistic account of moral ontology, against all competitors. Moral naturalists believe facts about morality, that is facts about irreducibly categorical norms, are identical to or constituted by some domain of natural facts. Most often this domain is facts about the flourishing and languishing of sentient beings. That being said, not all naturalists think a full and extensive account of moral ontology can be cashed out. We can be sure that the vast bulk of moral reality is constituted of facts about flourishing and languishing, even if there might be some problems at the fringes of moral experience. As long as the naturalist is aiming at merely identifying constitutive features of morality, and not a complete identity, counter examples lose their bite as long as they are few and far between, at the fringes of our moral experience.

The Conceptual Link

When deliberating what they should do people often forgo moral predicates altogether, and simply talk about the natural features of an action or situation. That it's perfectly natural to talk about morality without ever explicitly mentioning moral terms strongly suggests an intimate connection between moral concepts and the relevant natural concepts. Likewise, people often ask of themselves or others rhetorical questions like "what could it hurt?" That these questions are in fact rhetorical and not intended to be open ended for answering further goes to shows this strong conceptual connection. It is natural for people to speak as if, in the absence of anything that could be hurt or harmed by ones actions, there is not even conceptual possibility that those actions would be wrong. Now, I wont go as far to say that moral language can be reduced to natural language, I agree with the consensus of contemporary philosophers that G.E. Moore put analytic reductions of moral language, natural and non-natural, into the grave. Nevertheless, there is still a clear and resounding conceptual link between the two, which lends a great deal of credence to moral naturalism, and away from every other view.

The Supervenience of Morality on Nature

It's not controversial that moral facts seem to supervene on natural facts. That is to say it seems impossible for there to be a change in the moral features of some action or situation without there likewise being a change in the natural features. On any other view of moral ontology this supervenience is a highly mysterious coincidence. Why would the two be so intertwined across all possibilities as they are? Moral naturalists have an answer. Moral facts supervene on natural facts because moral facts are natural facts. Suppose that after every epic battle between Superman and some invading alien race, Clark Kent came into work the next day all cut up and bruised. After a while, you would start to suspect that Clark Kent just was Superman, that the two were the same person. Similarly, that any change in the moral facts necessitates a change in the natural facts seems to strongly suggest that moral facts are identical to or constituted by natural facts.

The Scientific Advantage

Because moral facts are identical to or constituted by natural facts, we are able to study them with the natural sciences. In fact, the moral naturalist would maintain that scientists have been studying morality for a very long time within the fields of biology, health sciences, psychology, sociology, economics and so on. We study what causes humans (and other sentient animals) to languish; what causes them to become sick, to suffer, or to die. We learn about morality when we study how different economic or government systems promote human flourishing, and which ones lead to languishing. What sorts of societies promote human flourishing. Just as the ancient Greeks studied the morning star, not realizing that their hypothesis and theories were likewise about the evening star, modern day scientists study the flourishing and languishing of humans (and other sentient animals), and thereby discover moral truth whether they realize it or not.

Evolutionary Psychology and Escaping Moral Skepticism

Evolutionary psychology offers us a compelling explanation of why we make the moral judgments we do: because these judgments drove our ancestors to act in ways that were beneficial to their survival and reproductive success. In other words, we make the judgments we do largely because these judgments were adaptive for our ancestors. This explanation carries a great deal of prima facie plausibility, is incredibly parsimonious, and is to some degree amenable to empirical confirmation and falsification. In other words, it has all the markings of a proper scientific hypothesis. On these considerations alone, the adaptive account of human moral psychology is very attractive.

But this adaptive account threatens moral knowledge. As Sharon Street argues in her paper The Darwinian Dilemma, it seems there is no connection between the truth of a moral judgement and its adaptivness. This is quite unlike judgements about physical reality that, if in error, can get you eaten by a predator, or plummeted off a cliff, or dead in a multitude of ways. Moral error doesn't seem to threaten ones chances of survival or reproductive success. And so, given the adaptive account of human moral psychology, we should expect our moral judgments to be largely (if not entirely) false.

Naturalists will be quick to point out that, on moral naturalism, moral error does in fact threaten ones chances of survival. Animals who are significantly in error about what causes and constitutes their own flourishing will not be able to maintain it, and thus die at a greater frequency. So on moral naturalism we can expect our moral judgements to be more or less aimed at truth, even in light of an evolutionary origin. At the very least, we should expect our moral judgements to be more no error prone than our physical judgements.

It seems naturalists are the only ones who can embrace the adaptive account without falling into extreme moral skepticism. And so non-naturalists of all sorts are forced into rejecting the adaptive account, most without any alternative explanation in sight. Theistic views might fair a bit better than the rest, in that they can fall back on a theistic account of human origins. They might say that God is directly responsible for human moral psychology, either by forming it ex nihilio or artificially guiding human evolution. But then they are adding a great deal more to the explanation than is necessary. And this loss of parsimony comes at the cost of an explanation that isn't even amenable to empirical confirmation or falsification. Even if theists can achieve consistency, there is nothing attractive about this alternate explanation.

But even with this, the theistic account explains too much. If God guided the evolution of human moral psychology, then it's very strange that our moral judgements are, in many respects, so error prone. There is and has always been great controversy surrounding ethical topics, and in the present it manifests in topics like abortion, euthanasia, sexuality, racial equality, gender roles, and so on. And, because of this, some significantly large portion of us must be or have been in error about these very important topics. But moral error leads to wrongdoing, something God supposedly wants us to avoid. It's very odd, then, that God would get involved with human evolution but not, as it seems, finish the job. Again naturalists will point out that, just as naturalism wards off threats of skepticism, it still leaves enough room for moral error. After all, evolution by natural selection is a messy, imperfect process. It does not care about our epistemic situation, and selects only by survival. And so on the adaptive account it's not surprising that we would have a handful of controversial topics here and there, where humans are generally not well equipped for discerning moral truth.

And so moral naturalism out competes theistic accounts of moral ontology twofold, and all other non-natural non-theistic views once over. With this, moral naturalism stands as the best account of moral ontology, since it's compatible with (without falling into deep moral skepticism) our best account of moral psychology.

The Ontological Parsimony

Moral naturalism is without the spooky metaphysical baggage of non-natural and supernatural views. It looks to the natural world, rather than to the supernatural, to explain moral ontology and, in doing so, only commits us to the existence of things everyone believes in anyway: the sorts of things a scientifically informed world view would contain. One doesn't need to believe in gods, or platonic forms, or mystical forces to believe in moral reality. One need only recognize objective facts about the flourishing and languishing of sentient beings, to find a solid ontological foundation for good and evil.