(1) The best explanation is the explanation with the overall greatest balance of intrinsic probability and accuracy.
(2) Naturalism is an intrinsically more probable explanation than theism.
(3) Naturalism is a more accurate explanation than theism.
In my previous post, I evaluated Lowder’s defence of (1), and in this post I will evaluate his defence of (2) and (3).
Is naturalism intrinsically more probable than theism?
With regards to (2), Lowder tries to show that naturalism is more linguistically modest than theism. Our discussion in the previous post revealed that this means very little, for it is ontological modesty that counts. Lowder, however, gives us no reason to think that naturalism is more ontological modest than theism. Indeed, it seems to me that theism wins here. Since naturalism is the view that physical reality is all that exists, most versions of naturalism affirm that physical reality is eternal in that either (i) there exists one universe that has existed for an infinite number of events, or (ii) there exists a multiverse that comprises an infinite number of universes. Either way, this version of naturalism asserts the existence of an infinite number of events or universes. However, the hypothesis that “God created the universe” (let’s call this hypothesis “theism”) asserts the existence of God and a finite number of events only. Thus, theism is more ontologically modest than the most prominent forms of naturalism, since the former postulates the existence of a finite number of entities, whereas the latter postulates the existence of an infinite number of entities. Nevertheless, the salient point is that Lowder has not shown that naturalism is a simpler hypothesis than theism.
Is naturalism a better explanation than theism?
Next, Lowder attempts to show that naturalism explains seven facts better than theism explains. Recall that Lowder wishes to use Bayes’ Theorem to do this (which is the incorrect way to use Bayes’ Theorem with Inference to the Best Explanation (IBE), but we will ignore this problem here). Let’s now discuss the seven facts.
The first fact is that the universe (i.e. physical reality) exists. Why does naturalism explain the existence of the universe better than theism does? According to Lowder,
If naturalism is true, then physical reality must exist. That’s just part of what naturalism means. … If theism is true, however, … God could have chosen to create nothing at all. … So because the physical has to exist on naturalism but does not have to exist on theism, it follows that the existence of physical reality is evidence favoring naturalism over theism.
There are several problems with this argument. First, most (if not all) theists understand theism to be the view that (T) “there exists a transcendent Creator of the universe”. But (T) entails that the universe exists; (T) cannot be true if there is no universe. Hence, as with naturalism, theism entails the existence of the universe and, consequently, naturalism and theism “explain” the universe equally well.
Second, Lowder confuses P(E|H) with P(H|E) (or with P(H|E & B)). We are not asking whether H (e.g. naturalism) entails E (e.g. that the universe exists) but, rather, whether H is more probable given E (and our background knowledge). Since Lowder is concerned exclusively with P(E|H), he does not use Bayes’ Theorem at all but, rather, he simply appeals to one clause on the right hand side of Bayes’ Theorem (let’s call this the “Entailment Fallacy”). Hence, since Lowder commits the Entailment Fallacy, he has not shown that the existence of the universe increases the probability of naturalism.
Third, Lowder does not explain how naturalism explains the existence of the universe. In fact, there is no explanation whatsoever for the existence of the universe in the phrase “naturalism is true”. On the other hand, the phrase “there exists a transcendent Creator of the universe” actually offers and explanation, namely, that God (the transcendent being) created the universe. Therefore, contra Lowder, theism is a better explanation of the existence of the universe than naturalism.
Finally, Lowder ignores our background knowledge about the universe. However, since we are using Bayes’ Theorem, we wish to know P(H|E & B), where “B” is our background knowledge. Now, most scholars agree that the universe is contingent, fine-tuned, and appears to have a beginning. But this forms part of our background knowledge. And if we include this knowledge in our assessment, then theism is a better explanation than naturalism because, unlike the latter, the former explains the contingency, fine-tuning, and appearance of a beginning. Therefore, Lowder’s first piece of evidence for naturalism turns out to actually support theism.
The second fact that Lowder appeals to is (F2) “that science has been so successful without the supernatural”. According to Lowder, since the vast majority of successful scientific theories do not postulate the existence of supernatural entities, the success of science is best explained by naturalism. The reason for this, says Lowder, is because “such explanatory success is just what we would expect on naturalism”. This argument, however, has three problems.
First, Lowder again commits the Entailment Fallacy. He thinks that, if naturalism entails (F2), then naturalism is more probable given (F2). But this reasoning is not Bayes’ Theorem and it ignores the rest of the clauses in the theorem. Consequently, Lowder has not really addressed the issue about whether (F2) renders naturalism more probable than theism.
Second, the development of modern science is largely due to theism, especially Christian theism. The ancients viewed the cosmos as an organism; however, Christian thinkers challenged this view by asserting that, since God created an orderly cosmos, the cosmos is more like a machine that can be understood best through empirical investigation. This theistic understanding of the cosmos propelled the birth of modern science. As Del Ratzsch remarks,
It is worth keeping firmly in mind that given the path which human history has actually taken, had there been no Christian intellectual context, there might well have been no modern science (Ratzsch 2010:66).
Thus, theism, especially Christianity, entails that the vast majority of scientific theories will postulate the existence of physical things and/or natural events only (since this is how God designed the universe). In other words, (F2) is just what we would expect on theism.
Finally, Lowder fails to mention that the scientific method presupposes methodological naturalism, which is the view that scientists should proceed as if no supernatural realm exists. As Victor J. Stenger (2012:26) notes,
The scientific community in general goes along with the notion that science has nothing to say about the supernatural because the methods of science as they are currently practiced exclude supernatural causes.
But if science is practised as if every event has a natural cause, then obviously we should expect (F2), even if theism is true. But how, then, can science support naturalism if the scientific method presupposes naturalism?
The third fact is “that complex life evolved from simple life”. Naturalism is supposed to be more probable than theism given this fact. But why think this? According to Lowder, “If naturalism is true and life exists, evolution pretty much has to be true. But if theism is true, God didn’t have to use evolution.” Here, again, Lowder commits the Entailment Fallacy, that is, Lowder is not trying to show that naturalism is more probable given evolution but, rather, that naturalism entails evolution. However, even his argument for this inconsequential premise fails, since the truth of naturalism does not entail the occurrence of evolution. It is possible that both naturalism is true and evolution is false. Hence, Lowder has not yet shown that naturalism is the best explanation of evolution.
Nonetheless, Lowder continues,
Furthermore, since theism says that at least one mind existed before any physical matter, it gives a reason to expect that any other minds are fundamentally nonphysical. But that, in turn, leads us to predict conscious life was created independently of nonconscious life, contrary to what evolution claims. So theism predicts that evolution is false.
This is a strange claim because that “other minds are fundamentally non-physical” does not imply that “conscious life was created independently of nonconscious life”. This is a non sequitur. Moreover, it is no secret that the conscious problem (i.e. the problem of how consciousness commences in an unguided evolution process) is unsolved (see Smith 2010) and, thus, evolution does not require that consciousness was produced in a specific way. Hence, theism does not predict that evolution is false (some theists are quite open to evolutionary theory).
Fact number four concerns “the biological role (and moral randomness) of pain and pleasure”. The idea here is that pain and pleasure are the product of evolution because they aid in survival and they sometimes occur for no usefulness whatsoever (such as when an animal burns in a forest fire). This fact, says Lowder, is entailed by naturalism but not by theism and, therefore, it increases the probability of naturalism. In response, we should point out, first, that Lowder once again commits the Entailment Fallacy by confusing P(E|H) with P(H|E &B). Second, naturalism does not entail the biological role of pain and pleasure, since such an evolutionary process would not necessarily occur if naturalism were true. Finally, the theist who believes that God guided the evolutionary process will say that the biological role of pain and pleasure is exactly what we should expect on (their understanding of) theism. Consequently, some forms of theism do entail the fourth fact.
Lowder’s fifth point is that “naturalism is the best explanation for the fact that human minds are dependent upon the physical brain”. There is a direct correlation between consciousness (i.e. human minds) and the brain. A stressed mind, for example, affects the brain’s state. The problem, according to Lowder, then, is that this “is much more probable on physicalism, which says that the mind is made only of physical matter, than it is on dualism, which says says that the mind is made of two substances (the physical and the mental)”. This is a weak argument. First, naturalism does not entail physicalism because naturalism can be true even if no minds and/or brains exist. Second, many theists are physicalists with respect to the mind/brain relation; theism simply does not entail dualism.
Finally, Lowder does not show that naturalism explains this fifth fact. That “naturalism is true” is no explanation whatsoever of mind/brain dependency. Indeed, how can naturalism explain consciousness? We know that elementary particles, such as photons, are not conscious. We also know that when a group of such particles come together they do not become conscious. An atom, the Eiffel Tower, or the entire universe, for example, are not conscious. We also know that the matter that our brains are made out of is completely replaced with new matter every few years, and yet we remain the same person. How does naturalism explain this? If Lowder’s argument is to succeed, he must at least show us how naturalism explains the emergence of consciousness from an arrangement of particles, why only brains and not other complex arrangements (such as the entire universe) are conscious, and how human minds are not destroyed when the matter in the correlating brain changes.
Furthermore, since Lowder does not show that naturalism explains mind/brain dependency, and since theism offers such an explanation (God created human persons such that there is a correlation between their minds and their brains), theism is clearly the best (and only) explanation of mind/brain dependency.
“Naturalism is the best explanation for the neurological basis of empathy and apathy, including some moral handicaps”, is Lowder’s sixth point. In other words, naturalism best explains the fact that some people are morally handicapped due to certain brain abnormalities. However, here again Lowder commits the Entailment Fallacy. He says, “the fact that at least some moral handicaps can be explained neurologically is much more probable on naturalism than on theism”. He has got it the wrong way round: the question we are interested in is whether naturalism is much more probable given moral handicaps. Moreover, it should be noted that Christian theism teaches that suffering exists because the world is in a fallen, imperfect state. Hence, brain abnormalities is just what we would expect if Christian theism is true.
Finally, Lowder argues that “naturalism is the best explanation for nonresistant nonbelief in God”. He explains,
At least some of the people who deny God’s existence are nonresistant nonbelievers. … Such nonbelievers are open to having a relationship with God—in fact, they may even want it—but are unable to have such a relationship. … On naturalism, blind nature doesn’t care whether anyone believes in God and so the fact of nonresistant nonbelievers is hardly surprising. On theism, however, … we would expect a perfectly loving God to always make a meaningful relationship available to those He loves.
In response, we should note that Christian theism teaches (and thus implies) that most people will not believe in God (or that the path to righteousness is narrow). Such people do not necessarily deliberately resist God but, rather, they may have overriding desires (fame, fortune, success, etc.). And those who are sincerely seeking a relationship with God will eventually find it. Unfortunately, Lowder does not cite any reliable study that shows that some of those who sincerely and constantly seek God never end up believing in God. Nevertheless, even if this were the case, it is plausible that such nonresistant nonbelievers never enter into a relationship with God because God knows that, if they were to enter into a relationship with Him, they would eventually hate it and rebel against God anyway.
Moreover, unlike theism, naturalism does not explain why the vast majority of people have an inner intuition that a supernatural realm exists, and why some people are nonresistant nonbelievers. As Lowder notes, “blind nature doesn’t care whether anyone believes in God” because evolution is concerned with survival. Thus, if naturalism and evolution are true, then it remains inexplicable as to why evolution produced such religious beliefs and tendencies.
In conclusion, I do not think that Lowder has offered a convincing (or powerful, or substantive, or coherent) defence of naturalism. His use of Inference to the Best Explanation and Bayes’ Theorem is suspect, and his pieces of evidence for naturalism are extremely weak.
Ratzsch, D., 2010. The religious roots of science. In: Stewart, M.Y. (Ed.), Science and Religion in Dialogue. Wiley-Blackwell, Malden, Massachusetts, pp. 54–68.
Smith, C.U.M., 2010. Darwin’s unsolved problem: The place of consciousness in an evolutionary world. Journal of the History of the Neurosciences 19, 105–120.
Stenger, V.J., 2012. God and the folly of faith: The incompatibility of science and religion. Prometheus Books, Amherst, New York.