Chapter 1: Farewell to Philosophical Naturalism
by Paul K. Moser and David Yandell
In their essay, Moser and Yandell argue that although the methods and resources of the empirical sciences reliably track the truth in certain domains, there is insufficient justification for extending those methods and resources to such a degree that the empirical sciences have a monopoly over all domains of inquiry. Put another way, since some knowledge comes to us by way of physical sense experience of an externally existing material world, it does not follow that all knowledge comes to us by way of physical sense experience and that all existing entities are material. Moser and Yandell write:
"A basic question is whether there is a legitimate form of philosophical procedure, often called 'first philosophy,' that has ontological authority but employs methods 'prior to' or at least not based on sense experience or the empirical sciences. In particular, can a philosopher operating without reliance on sensation or the empirical sciences legitimately engage in inquiry that posits real objects or at least yields genuine truths? Naturalists say no; antinaturalists, yes" (p.3-4).
I should note that there are different varieties of "naturalism." As Michael Rea observes in his essay in chapter 5 of this volume, "naturalism is a house divided." In order to deal with this, Moser and Yandell attempt to define the two major components of naturalism--ontological and methodological1--carefully:
"Core ontological naturalism: every real entity either consists of or is somehow grounded in the objects countenanced by the hypothetically completed empirical sciences (that is, in the objects of a natural ontology).
Core methodological naturalism: every legitimate method of acquiring knowledge consists of or is grounded in the hypothetically completed methods of the empirical sciences (that is, in natural methods)" (p.10, original italics).The locution "hypothetically completed" serves to appreciate the fact that many naturalists depend on future findings of the empirical sciences, since the present states of physics and chemistry are incomplete. Naturalist ontological and methodological commitments are not represented in full by today's understanding of physics and chemistry, but those commitments are presumably well-approximated by the empirical theories of today. Thus, Moser and Yandell seek to assess the version of naturalism that would be defined by a future, hypothetically completed version of empirical science rather than whatever incomplete versions of naturalism exist today.
Moser and Yandell go on to clearly state that these core commitments put the empirical sciences at the very center of the naturalist world view:
"...[Core ontological and methodological naturalism] acknowledge the empirical sciences as the single standard for genuine metaphysics and epistemology...For brevity, let us call the conjunction of these two positions Core Scientism" (p.10, original italics).Core Scientism, by combining both core ontological and methodological naturalism, gives the empirical sciences a monopoly in the marketplace of knowledge. Really existing entities can only be said to exist once the empirical sciences license their existence by a sort of "stamp of authenticity." Furthermore, any properties or relations really existing entities might have are only detectable by way of the methods or tools of the empirical sciences. Thus, under the thesis of Core Scientism, any entity not sanctioned by the hypothetically completed empirical sciences does not exist, and any proposition about the world not verified by the hypothetically completed empirical sciences is not known to be true. Period.
Now, Moser and Yandell go on to criticize Core Scientism in a number of technical ways, but I will here focus on what I consider to be their strongest and most obvious criticism of Core Scientism: the fact that it is self-defeating.
"The self-defeat of Core Scientism would result from its failing to be included in or approved by its own proposed single standard for methodological and ontological integrity: the (hypothetically completed) empirical sciences. By its own proffered standard...Core Scientism would suffer defeat" (p.13).The support for the charge of self-defeat is fairly easy to see. One must simply ask the question, "By virtue of which empirical methods was the statement Core Scientism is true validated?" The answer, ironically, seems to be "none." Moser and Yandell state the matter clearly:
"Core Scientism is not itself a thesis offered by any empirical science. In particular, neither its ontological component nor its methodological component is a thesis of an empirical science. Neither component is represented in the empirical scientific work of either physics, chemistry, biology, anthropology, psychology, or any other natural or social empirical science" (p.10).But, if Core Scientism is not a thesis of any empirical science, then, by Core Scientism's own standard, it cannot be not known to be true. Thus, to believe Core Scientism to be true immediately gives one reason to reject that Core Scientism is true. Whenever a proposition X is such that the very belief that X is true entails that one not believe X is true, proposition X is self-defeating. The proposition "Core Scientism is true" appears to suffer precisely from this self-defeating property. The only rationally permissible option--that is, the only way to avoid a contradiction in one's beliefs--is to reject Core Scientism.
Moser and Yandell do anticipate a popular objection to this conclusion. This objection asserts that Core Scientism derives its justification from a future, hypothetically completed empirical science. The fact that today's empirical sciences do not offer "Core Scientism is true" as an empirically tested hypothesis, so the objection goes, is no barrier to Core Scientism's coherence. Moser and Yandell have two responses to this objection.
First, they argue that the appeal to future, unknown findings of empirical science is unsupportable: "A general problem is that predictions about what the completed sciences include are notoriously risky and arguably unreliable. The revolutionary history of the sciences offers no firm basis for reasonable confidence in such predictions" (p.11). This criticism strikes me as quite decisive. If Core Scientism's justification is presently sealed behind some indeterminable time frame in the future, no one today can properly claim to "know" that the justification both exists at that future time and, by virtue of its future existence, justifies Core Scientism today. One could just as easily claim to have gazed into a crystal ball and found that future science fails to vindicate Core Scientism in the future. So long as the future evidence of empirical science remains behind the veil of time, there is no way to adjudicate whose claims over future science's findings are correct. Thus, the most charitable position to hold today is that Core Scientism is simply unsupported--it may receive empirical support at some point in the future, but until such time, it carries no authority today.
Second, Moser and Yandell go on to argue that the nature of empirical science is such that no future finding of science could plausibly be expected to vindicate Core Scientism: "[N]othing in the current empirical sciences makes it likely that the completed sciences would include Core Scientism as a thesis" (p.11). They support this claim by highlighting a key distinction between philosophical claims and scientific claims. They argue that Core Scientism aspires to monopolize all of reality and knowledge, but only philosophical claims are so monopolistic in nature:
"The problem with Core Scientism is its monopolistic posture, a posture common among philosophical claims. It makes a claim about every real entity and every legitimate method for acquiring knowledge. The empirical sciences, for better or worse, are not thus monopolistic; nor do we have any reason to think that they will become so....the empirical sciences, individually and collectively, are logically neutral on such matters as the existence of God, the reliability of certain kinds of religious experience, the objectivity of moral value, and the reality of thinking substances....We have no reason to suppose that the hypothetically completed empirical sciences differ from the actual empirical sciences in this respect" (p.11, original italics).Moser and Yandell's second reply here again strikes me as decisive. The empirical sciences appear to be in the business of investigating certain systems or domains. The variegated instruments of the sciences are always calibrated to detect certain entities and ignore others. There are no instruments of the sciences calibrated to detect everything. To modify a salient analogy from Edward Feser, the empirical sciences can be likened to a metal detector. Whereas a metal detector is an excellent tool for finding metallic objects, it is incapable of detecting anything non-metallic. Likewise, each subdiscipline of the empirical sciences is well-suited for detecting entities within its own specific domain but useless everywhere else. Each of the subdisciplines of science, therefore, is no better-suited to make claims about what does or does not exist outside of its respective domain than a metal detector is suited to make claims about what does or does not exist outside of the domain of metallic objects.
Furthermore, Core Scientism does not stand to gain from the conjunction of all the disparate domains of the individual branches of the empirical sciences. Suppose one were to grant that metal detectors do not, by themselves, provide a complete account of what exists--i.e., some objects might exist that the metal detector cannot "see." Suppose further that one added a detector for many more kinds of entities--e.g. a wood detector, a water detector, a meat detector, etc.--and claimed that the conjunction of all these detectors did exhaust all the possible kinds of entities in existence. Would the summation of all these detectors sufficiently cover all really existing entities and all legitimate modes of detection? Well, that depends. It depends on how many kinds of entities really exist and how many detectors there are.
Suppose we have 99 distinct detectors, each of which reliably detects one of 99 distinct kinds of entities. Does the summation of all 99 detected entities, by itself, tell us one way or the other whether there are only these 99 entities in existence? Surely, it does not. Perhaps there are really 100 distinct entities in existence, or 1,000, or 100,000. All the detectors alone can tell us is that the 99 entities detected exist. They do not give us any extra information about what does not exist. No matter how many individual detectors we happen to have, they are incapable of disclosing to us whether they jointly capture all of reality. This is so because these detectors simply are not in the business of making claims about all of reality; instead, they are limited to making claims within their respective domains of specialization. In order to know whether there are 99, and only 99, distinct entities in existence or not, we need some kind of tool that is, by its nature, different from the individual detectors--something that operates at the level of universals and absolutes rather than the level of particulars. In other words, in order to know if our 99 detectors summarily capture all of reality, we need to independently--by some other method--determine how many entities exist. Once we have such a finding in hand, then we can compare that number to the number of detectors we have. If the numbers are equal, then the detectors are sufficient; if the numbers are unequal, then the detectors are insufficient. What is crucial is that there is no way those detectors could, all by themselves, provide a comprehensive account of both what does and does not exist.
Insofar as the individual disciplines of empirical science can be likened to the individual detectors in the previous analogy, the empirical sciences--individually and collectively--are simply not in a position to make universal or monopolistic claims about everything that exists. As such, Moser and Yandell appear to be on target when they assert that future science, whatever it might find, will not find the empirical support necessary to vindicate Core Scientism.
Core Scientism is thus left in a rather dismal situation. On the one hand, its lack of empirical support by present-day science renders the position, by its own standard, utterly unsupported by anything known today and, therefore, self-defeating; on the other hand, its inability to siphon support from future findings of empirical science strips the position of any possible support for itself anywhere in the future.
Moser and Yandell conclude that Core Scientism--which includes ontological and methodological naturalism--is "either self-defeating or ineffectively stipulative."2 They do record, though, that their position is not to be taken as a rejection of empirical science wholesale. Just like a metal detector is extremely useful for finding metallic objects even though it is not equipped to find all objects in existence, so the empirical sciences are extremely useful in their own domains even though they are not equipped to deal with everything in existence. Thus, one appears to be best served by embracing the empirical sciences as reliable within their respective domains, but refraining from granting those sciences a monopoly over all that exists and all that can be known. In short, one is best served by rejecting ontological and methodological naturalism.
1. The term "ontology" is philosophy-speak for "an account of what exists." Materialists, for example, permit only material objects into their ontology; dualists permit material objects and immaterial mental objects into their ontology; theists permit God into their ontology; etc. The term "methodology" (or "epistemology") here refers to "how we acquire knowledge." Rationalists, for example, hold that we can acquire genuine knowledge through a sort of rational intuition--by thinking carefully about concepts and their logical relations. Empiricists, by contrast, hold that we can acquire knowledge by way of sensory experience.↩ 2. The option "ineffectively stipulative" is discussed at length in Moser and Yandell's essay, but I omitted commenting on it here for the sake of brevity. To avoid the charge of self-defeat, naturalists can make a linguistic maneuver to get Core Scientism going. That is, they can simply stipulate that the empirical sciences definitionally include Core Scientism's commitments. Moser and Yandell say "This would amount to a vindication of Core Scientism by semantical fiat" (12). They hold this maneuver is "ineffective" because anyone can redefine their terms however they see fit. For example, an opponent of Core Scientism could just as easily define empirical science to exclude Core Scientism, and this would be just as authoritative as a definition preserving Core Scientism--which is to say, not authoritative at all.↩