bookmark_borderThe Evidential Argument from Moral Agency (AMA) Revisited

I want to revisit Paul Draper’s very interesting argument from moral agency against metaphysical naturalism.[1]

Informal Statement of the Argument

We know that moral agents exist. If we ignore for a moment the evidence for moral agents–i.e., independent of the evidence for moral agents–we have much more reason on theism than on naturalism to expect the existence of moral agents.

Let us start by considering metaphysical naturalism. If naturalism is true, then it is extremely improbable that there exist such things as unembodied minds like souls, spirits, ghosts, etc. Thus, in a naturalistic world, the existence of moral agency virtually requires the existence of living beings. Therefore, on the assumption that naturalism is true, we would expect that any world without (physical) life would also be a world without any moral agents.

Now consider theism. On the assumption that theism is true, we have several reasons to expect moral agency, reasons we do not have on the assumption that naturalism is true. First, moral agents, by definition, have moral value. That fact is irrelevant to the probability of their existence on naturalism, but it is relevant to the probability of moral agents on theism, which posits a personal God who is, among other things, perfectly morally good.

Second, moral agency requires moral responsibility, which in n turn requires libertarian free will. We have much reason to expect libertarian free will on the assumption that theism is true than on the assumption that naturalism is true.

Third, thanks to recent discoveries in physical cosmology, we now know that our universe is incredibly well “fine-tuned” for life. By itself, the fine-tuning data shows that the prior probability of life given naturalism is extremely low. But when we combine the fine-tuning data with the facts of moral agency, the argument becomes much stronger: embodied moral agency is extremely improbable on the assumption that naturalism is true.

Formal Statement of the Argument

Abbreviations:

>!: much greater than
E: there exist embodied moral agents
T: theism: the hypothesis that there exists an omnipotent, omniscient, and morally perfect person (God) who created the universe.
N: metaphysical naturalism: the hypothesis that the universe is a closed system, which means that nothing that is not part of the natural world affects it.

Argument Formulated:

(1) E is known to be true.
(2) Pr(E | T) >! Pr(E | N).
(3) N is not intrinsically much more probable than T.
(4) Other evidence held equal, Pr(T) > Pr(N).

Objects to the Argument from Moral Agency (AMA)

I’m  going to consider various objections to AMA’s premises, in a roundabout order.



Objections to (2)

Objection: Theism is not needed to explain the data about moral agency, including fine-tuning. This is because the hypothesis that there exist multiple or even infinite universes explains the data as good or better than theism. Since the physical laws in each of these universes are random, there is bound to be at least one, if not many, life-permitting universe. We just happen to live in (one of the very few) life-permitting universes.

Reply:  At first glance, the multiverse hypothesis (M) seems irrelevant to the argument from moral agency, since (2) compares the antecedent probability of E on T to the antecedent probability of E on N, not N conjoined with an auxiliary hypothesis about the multiverse. So how could M be relevant to (2)?

Those of you who have read my other recent postings can probably predict what I’m going to write next. Using the probability calculus, we can measure the effect that an auxiliary hypothesis like M has on Pr(E/N). In order to assess the evidential significance of an auxiliary hypothesis like M, we would simply need to consider a weighted average, as follows:

Pr(E/N) = Pr(M/N) x Pr(E/M&N;) + Pr(~M/N) x Pr(E/~M&N;)

This formula is an average because Pr(M/N) + Pr(~M/N) = 1. It is not a simple straight average, however, since those two values may not equal 1/2.

The weighted average formula above gives us some insight into what would need to be the case in order for M to be a good defeater for the argument from moral agency. I assume we all agree that the second half of the right-hand side of that equation, Pr(~M/N) x Pr(E/~M&N;), is not going to be useful for deriving a high value for Pr(E/N). (Otherwise, there would be no need to introduce M in the first place!)

So we’re stuck with the first half of the right-hand side: Pr(M/N) x Pr(E/M&N;). In order for M to be a good defeater of the FTA, then, Pr(M/N) x Pr(E/M&N;) needs to be high, the higher the better. The problem, however, is that we have little or no reason to believe that Pr(M/N) is high, i.e., we have little or no reason on naturalism (alone) to expect multiple universes. If Pr(M/N) is not high, then there is no reason to believe that Pr(E/N), as a weighted average of Pr(M/N) and Pr(~M/N), is high. So, unless there is independent evidence for M–i.e., evidence that is independent of the evidence for E–it appears that using M as a defeater against the argument from moral agency fails.

Furthermore, not only can we calculate the impact of M on Pr(E/N) as a weighted average, we can also calculate the impact of M on Pr(E/T) also as a weighted average.

Pr(E/T) = Pr(M/T) x Pr(E/M&T;) + Pr(~M/T) x Pr(E/~M&T;)

In order to have a true “apples-to-apples” comparison, we would need to compare both Pr(E/N) and Pr(E/T) as weighted averages. On the assumption that theism is true, it is far from obvious that God would create only this universe.[1] This is significant because the higher the value of Pr(M/T), the closer the value Pr(E/T) will be to Pr(E/M&T;). Since we are ultimately interested in the ratio of Pr(E/T) to Pr(E/N), it seems far from obvious that M significantly decreases that ratio. (In fact, I wouldn’t be surprised if the “apples-to-apples” comparison ultimately strengthened the argument by increasing the ratio of Pr(E/T) to Pr(E/N), but I don’t need to show that in order to refute the objection based on M.)

Objections to (3)

Objection: (3) is false. N is intrinsically much more probable than T. N only asserts that supernatural beings do not exist, while T asserts that a very specific kind of supernatural being exists. Thus, N asserts much less than the proposition that nothing at all exists, while T says much more than the proposition that something exists. Thus, N is intrinsically much more probable than the proposition that nothing exists, while T is intrinsically much less probable than the proposition that something exists.[1]

Reply: I find this objection very persuasive. I am tempted to conclude that this objection is also decisive, but theories of intrinsic probability are extremely controversial. On the other hand, theories of intrinsic probability are extremely controversial. And I know of no non-question-begging reason to believe that (3) is true. Even without a decisive or conclusive argument for the conclusion that N is intrinsically much more probable than T, this objection does constitute a solid reason for doubting (3).

Objections to (1)

Objection: This argument depends upon the assumption that we have libertarian free will, which is dubious. Only 16% of professional philosoph
ers believe we have libertarian free will; the rest are either compatibilists or determinists.

Reply: I have called the argument from moral agency the “best argument for theism” without calling it a “good argument.” Part of the reason why is that I am undecided between libertarianism and compatibilism. If libertarianism is false, then so be it. But what interests me about the argument from moral agency is how it directly solves one of the major defects of what I call ‘standard’ fine-tuning arguments.

Standard fine-tuning arguments just assume that God would want to create embodied moral agents, but fail to provide a reason why we should believe that. In contrast, the argument from moral agency directly deals with that problem. It provides a plausible explanation for why, if theism is true, we should expect moral agents. This does not show that the existence of embodied moral agents is more probable than not on the assumption that theism is true. What it does show, however, is this. Given that moral agents of any kind (i.e., embodied or otherwise) is antecedently much more probable on theism than on naturalism, the fact that there are embodied moral agents is much more probable on theism than on naturalism. (Again, please review what I wrote earlier about the ratio of Pr(E/T) to Pr(E/N).) That is the inference that I find particularly interesting (and persuasive).

Back to the objection: I think the objection correctly points out that the argument from moral agency seems to have the concept of libertarian free will built into the definition of “moral agent.” If that is so, then we can’t use our knowledge of our own existence, by itself, as evidence for (1). We also need evidence that we possess libertarian free will. In my opinion, this is probably the strongest objection to the argument. (This assessment could obviously change in response to a robust defense of libertarian freedom.)

Objections to (4)

Objection: The fact that embodied moral agents exist hardly exhausts what we know about moral agents. We also know facts about the variety and frequency of conditions that severely limit our freedom, facts which are antecedently more probable on N than on T.[2] Thus, one can’t conclude that T is true, solely on the basis of moral agency, without committing the fallacy of understated evidence.


Reply: AMA, by itself, doesn’t commit the fallacy of understated evidence, since its conclusion is merely that moral agency provides prima facie evidence favoring T over N, not ultima facie evidence. I consider it an open whether the fully stated evidence regarding moral agency–in other words, whether the general fact of moral agency combined with the more specific facts about the variety and frequency of conditions that severely limit our freedom–favors T or N.

Conclusions and Prospects

If I were to rank the objections from strongest to weakest, I would rank the objection to (1) as the strongest objection, followed by the objections to (3), (2), and (4), respectively. Suppose, however, someone presented a robust, even overwhelming, defense of libertarian freedom and hence of (1). Where would that leave this argument?

I strongly suspect that, once there is some reasonably well-accepted theory of intrinsic probability, it will support the claim that naturalism is antecedently much more probable than theism. Assume, for the sake of argument, that prediction is correct and premise (3) is false. While the argument from moral agency, as it stands, would be unsound, we would still be left with the argument’s premise (2), which, in my opinion, is powerful. How then could a philosopher build an explanatory argument for theism, based upon moral agency, that is also inductively correct? In my opinion, the most promising option would be to construct a cumulative case utilizing multiple, independent lines of evidence, since the cumulative effect of multiple, independent lines of evidences can be enough to overcome even an extremely low prior probability.

Notes

[1] Paul Draper, “Terrestrial Suffering and Cosmic Fine-Tuning: Parallel Problems for Theism and Naturalism.”  American Philosophical Quarterly 41 (2004): 311-321.


[2] Paul Draper, “Cumulative Cases,” in Charles Talioferro, Paul Draper, Philip L. Quinn, Blackwell Companion to the Philosophy of Religion (John Wiley and Sons: 2010), 414-24 at 421.

bookmark_borderIndex: The Evidential Argument from the History of Science (AHS)

Informal Statement of the Argument
If there is a single theme unifying the history of science, it is that naturalistic (i.e., non-supernatural) explanations work. The history of science contains numerous examples of naturalistic explanations replacing supernatural ones and no examples of supernatural explanations replacing naturalistic ones. Indeed, naturalistic explanations have been so successful that even most scientific theists concede that supernatural explanations are, in general, implausible, even on the assumption that theism is true. Such explanatory success is antecedently more likely on naturalism–which entails that all supernaturalistic explanations are false–than it is on theism. Thus the history of science is some evidence for metaphysical naturalism and against theism. Since metaphysical naturalism entails that no supernatural beings exist, including God, the history of science is some evidence for atheism.
Series Index
Part 1“: a summary and defense of Paul Draper’s explanatory version of AHS, plus some responses to objections
Part 2: Detailed Reply to Randal Rauser“: a refutation of Rauser’s argument that an auxiliary hypothesis to theism known as “transcendent agent” models of divine action refute AHS.
Part 3: Reply to Rauser on Defining Metaphysical Naturalism“: a refutation of Rauser’s claim that metaphysical naturalism is compatible with the existence of an interventionist God
Part 4: Reply to cl“: a point-by-point rebuttal to cl’s reply to AHS.
Part 5: Reply to RD Miksa: a rebuttal to Miksa’s reply to AHS.

bookmark_borderThe Evidential Argument from the History of Science, Part 3: Reply to Rauser on Defining Metaphysical Naturalism

Randal Rauser really doesn’t like the argument from the history of science (AHS). After I refuted his initial objections to AHS, he seems to have abandoned those objections. Instead, he now takes issue with the definition of metaphysical naturalism itself, a point he makes over the course of no less than three separate, additional replies. (See here, here, and here.) According to Rauser, metaphysical naturalism “is a vacuous cipher that is consistent with belief in the existence of an interventionist God.”

At first glance, his new approach seems like a stroke of genius. If metaphysical naturalism is consistent with theism, then it’s impossible for literally anything to be evidence favoring naturalism over theism. And therefore one doesn’t have to get bogged down in messy, contingent issues about which hypothesis (i.e., naturalism or theism) best explains the data; indeed, one doesn’t even have to deal with tricky issues about what counts as evidence! Instead, one can play the sort of semantic games which give philosophy a bad name, in which empirical evidence isn’t important. One might ask, “But what about all those high-falutin’ philosophers, from both sides of the aisle, like Plantinga, Swinburne, Moreland, Draper, Schellenberg, and Smith (to name just a few) who think that metaphysical naturalism is a serious alternative to theism?” I guess Rauser would say that he knows better than they do; they simply (and quite literally) do not know what they are talking about.

This is, of course, absurd. Just as it is misguided for noncognitivists to try to deny that theism is an explanatory hypothesis (by denying that “God exists” expresses a proposition), it is equally a mistake to try to deny that metaphysical naturalism is an explanatory hypothesis (by claiming that metaphysical naturalism is consistent with theism). But I’m getting ahead of myself. Lest I be accused of offering an inductively incorrect argument from authority, I want to consider his arguments.

Since Rauser pins so much of his latest batch of replies on my definition of metaphysical naturalism, let us begin by reviewing the definitions I’ve used throughout our exchange. Following Paul Draper, I’ve offered the following definitions.

physical entity: the kind of entity studied by physicists or chemists. Examples of physical entities include atoms, molecules, gravitational fields, electromagnetic fields, etc.[1]
causally reducible: X is causally reducible to Y just in case X’s causal powers are entirely explainable in terms of the causal powers of Y.[1]
ontologically reducible: X is ontologically reducible to Y just in case X is nothing but a collection of Ys organized in a certain way.[1]
natural entity: an entity which is either a physical entity or an entity that is ontologically or causally reducible to a physical entity.[1]
nature: the spatio-temporal universe of natural entities.[1]
supernatural person: a person that is not part of nature but can affect nature. Examples of supernatural persons include God, angels, Satan, demons, ghosts, etc.[1]
metaphysical naturalism (hereafter, “N”): the hypothesis that the universe is a closed system, which means that nothing that is not part of the natural world affects it.
theism (hereafter, “T”): the hypothesis that there exists an omnipotent, omniscient, and morally perfect person (God) who created the universe.

It is trivial to show, by substitution of synonyms for synonyms, that N contradicts T. According to T, God created the universe. Since God created the universe, God is not part of the universe. Furthermore, God’s act of creation of the universe is an act which, by definition, affects the universe. Therefore, T entails that a being (God) which is outside of the universe affected (created) the universe. Thus, T contradicts N, which denies the existence of any being that is not part of the natural world but somehow affects it.

Semantics

I’m going to start with Randall’s article, “Not Even Wrong: The Many Problems with Naturalism.”

1. Rauser begins by complaining that I failed to provide a definition of N: “Unfortunately, in his definitive list of definitions Lowder doesn’t provide a definition for metaphysical naturalism.” Rauser seems to have confused “definitive list of definitions” with “exhaustive list of definitions.” I provided the definition of N just a little bit farther down in the article, under the heading “Rival Explanatory Hypotheses.” I give there the same definition of N which I provide above. To his credit, however, Rauser attempts to reconstruct my definition of naturalism from the other terms. He arrives at a definition which, while not identical to my actual definition, isn’t horrible. (I will briefly address why I don’t care for his reconstruction at the end of this post.)

2. Next, he writes, “nature is defined in such a way that it encompasses whatever science describes in the future as either natural or in relationship with the natural.” As we have just seen from my actual definitions, however, this is an oversimplification. The phrase, “in relationship with the natural,” is ambiguous: it could include ontological reduction, causal reduction, or–here’s the important part–some other unspecified type of “relationship.” The definition of “natural entity” does not allow for any other type of relationship. But let’s put that aside. What, precisely, is the problem?

According to Rauser, “Lowder’s naturalism is consistent with science establishing the existence of a non-physical substance that interacts causally with the realm of nature.” And why is that a problem? Rauser writes that one such reason is that

it is possible that a future neuroscience may have reason to affirm the existence of a non-physical substance that interacts with the brain. In the same way that the existence of subatomic particles can be inferred from their effects, so it is conceivable that a soul could be inferred from its effects.

An entity is logically compatible with N if and only if either (a) it is a physical entity, or (b) it is ontologically or causally reducible to a physical entity. How, precisely, would a ‘soul’ be logically compatible with N? Rauser’s scientific ‘soul’ (hereafter, ‘shmoul’) cannot be ontologically reducible to one or more physical entities, since he says it is (or is made out of?) a “non-physical substance.” Thus, if a shmo
ul is compatible with N, that is because a shmoul is causally reducible to a physical entity. Is it? Is it an unembodied mind? For that matter, what are the causal powers of a shmoul? Can shmouls which are not somehow associated with a physical brain (i.e., ghosts) somehow affect physical entities? Can shmouls exist without a physical universe? Rauser says nothing about this. In ordinary English, however, a “soul” is not causally reducible to physical entities, i.e., a soul’s causal powers are not entirely explainable in terms of the causal powers of physical entities. So it’s hard to see how the existence of a “soul,” at least as that word is defined in ordinary English, could be consistent with N.

I want to emphasize that I don’t rule out the possibility of a future scientific discovery which could provide evidence for souls (or shmouls). If such evidence is discovered that would be evidence for T and against N. But then it follows from the probability calculus that the non-existence of souls is evidence for N and against T.

3.This same problem refutes Rauser’s argument that N is consistent with the existence of God.

So now we’ve identified that Lowder’s naturalism is consistent with the existence of an indefinite range of non-physical substances interacting in nature. Whether or not we can identify one of those substances as God from within scientific discourse is quite irrelevant. The point remains that Lowder’s naturalism is consistent with God interacting in the physical world.

Again, Rauser seems to have forgotten the role of “natural entity” in the list of definitions I provided earlier. Yes, N is consistent with the existence of natural entities which are not physical entities. Such entities, however, must be either ontologically or causally reducible to physical entities. The theistic God, however, is neither ontologically nor causally reducible to physical entities.

4. Similarly, this same problem refutes Rauser’s claim to have discovered a contradiction.

On the one hand, Lowder’s naturalism is open to the existence of non-physical substances causally interacting in the physical world. On the other hand, it categorically denies this. So which is it?

Again, Rauser seems to have forgotten the role of “natural entity.”

What About Abstract Objects?

Let’s move onto Randall’s article, “Prejudice Against Supernatural Persons.” He asks why metaphysical naturalists (in my sense of metaphysical naturalism) believe there are no supernatural beings, while being open to abstract objects? Draper answers this question well: “[W]hile our knowledge of nature may provide reason to believe that nothing is supernatural, it provides little basis for the further conclusion that nature is all there is.”[2] This is also why I don’t care for Rauser’s attempt at reconstructing my definition of metaphysical naturalism.

Addendum: Open-Ended Metaphysical Naturalism?

I want to revisit Rauser’s complaint that N, as I have defined it, is open-ended. Again, he writes, “Thus, nature is defined in such a way that it encompasses whatever science describes in the future as either natural or in relationship with the natural.” The worry seems to be that if physicists or chemists in the future were to suddenly start appealing to God or other supernatural persons in their theories, then, God or other supernatural persons would suddenly become physical entities, just by virtue of the fact that physicists or chemists have appealed to them.

I have two comments, one very minor and one substantive. The minor comment is that physicists and chemists do not today appeal to supernatural agents in their theories, so God and other supernatural persons are clearly not physical entities today. (Okay, I said that was a minor point.) The more substantive comment is this. One can easily revise and expand the definition of N as follows:

physical entity: an entity which is either (1) the kind of entity studied by physicists or chemists today; or (2) the kind of entity studied by physicists or chemists in the future, which has some sort of nomological or historical connection to the kinds of entities studied by physicists or chemists today.[3]

Thus, even if physicists or chemists of the future appeal to God in their theories, God would not be a physical entity because He “is not subject to laws relating him to atoms, fields, and the like, nor would he share any common origin with such entities.”[4]

Notes

[1] Paul Draper,  God, Science, and NaturalismOxford Handbook of Philosophy of Religion (ed. William Wainwright, Oxford: Oxford University Press, 2004), 272-303.
[2] Draper 2004, 279-280.
[3] Draper 2004.
[4] Draper 2004.