Core Reading for Chapter 4
2. Do Philosophical Theories Give Explanations?
The first issue we need to consider is whether there is any reason to link philosophical hypotheses with the role of explanation. In addition to the considerations already canvassed, there are two reasons. One concerns the nature of philosophical problems. The other concerns the link between the problem-solving ability of philosophical theories and explanatory power.
Robert Nozick thought that philosophical problems can be presented as problems about how something is possible, given certain facts (Nozick 1981, 8–11). These problems take the following form:
Given that r, how is it possible that p rather than that q?
Here are some illustrations of how familiar philosophical problems take this form:
There is the free will problem: Given that determinism (or:
indeterminism) is true, how is it possible that we have free will (rather than lack it)?
There is the problem of our knowledge of the external world:
Given that our sensory experience is consistent with our being brains in vats, how is it possible that we know that there is an external world (rather than not know this)?
And there is the problem of identity over time: Given that a concrete thing changes, how can it be the very same thing over time (rather than fail to be the same thing over time)?
In the above schema, we want an explanation of how it is possible that p is the case rather than that q is the case. Typically, the proposition that q is simply the negation of the proposition that p. What is then wanted is an explanation of how it is possible that p is the case rather than that not-p is the case. Our explanation is constrained by having to show how this is possible despite its being the case that r. The proposition that r apparently entails that p is false. For example, the proposition that the world is deterministic apparently entails that it is false that we have free will. Our task is then to explain how it is possible that we have free will despite the world’s being deterministic. The proposition that r need not be a well-established truth. It might only be a tentative theory or merely something assumed or taken for granted. Whatever the degree of support
for r happens to be, the problem is one about mutual consistency: how could the propositions that p and that r both be true? The proposition that r is apparently incompatible with the proposition that p.
Two ways of solving a philosophical problem present themselves.
We may provide the needed explanation by showing that the proposi-tions that p and that r are compatible, or by showing that, although they are incompatible, the proposition that r is false. A philosophical debate may then consist in one party seeking to show that r entails that not-p, whereas a rival party seeks to show that p and r are compatible, and so that r does not entail that not-p. (Other views about the debate are pos-sible. For example, someone might question whether there are such prop-ositions as the proposition that p or the proposition that r, and whether the sentences that appear to express these propositions are intelligible.)
There is currently a tendency among some philosophers to talk of a philosophical problem as consisting of various sentences or propositions being in “tension” with one another. Beware: “tension” is a weasel word.
Either it means that the sentences are (apparently) mutually logically incompatible or mutually highly improbable, in which case those phi-losophers should simply say that, or it is obscure what is being meant, in which case there is no reason why we should think that a problem has been stated.
In chapter 1, §6 we discussed G.E. Moore’s so-called proof of an exter-nal world and found it unsatisfactory. Moore’s argument is apparently question-begging. Another unsatisfactory feature of his argument is that even if Moore had proved that there is an external world, and shown that he knew that there was one, he would not thereby have solved the problem of the external world. The problem does not consist only in the problem of showing that there is an external world or only in the problem of showing that someone knows that there is an external world. The prob-lem consists in showing how anyone can know that there is an external world, given that all of our sensory experiences are consistent with our not perceiving an external world (Vogel 1993, 242). In one sceptical sce-nario we have the same flow of sensory experiences as we actually have, but we are brains in vats in the control of a mad scientist. In that scenario we do not have sensory experience of an external world. Moore does nothing to solve this problem. Proving that p is true does not thereby explain how it is possible that p is true given that r is true, where p and r are apparently incompatible (Nozick 1981, 10). Take an example from science. A proof (if we could have one) that the same side of the moon always faces the Earth (p) does not explain how it is possible that the same side of the moon faces the Earth, given that (r) the moon rotates on its own axis and orbits the Earth. Likewise, a proof that there is an
external world (p) does not explain how it is possible that we know that there is an external world, given that (r) our only evidence that there is one is apparently compatible with our not knowing that there is an external world.
Let’s turn to a second reason for linking philosophical hypotheses with the notion of explanation. How do you argue for a philosophical hypothesis? According to Russell, the success of a philosophical theory in solving problems that cannot otherwise be solved counts as evidence for that theory (Russell 1905, 45). Now if a philosophical problem is something that calls for an explanation, a theory that solves that problem thereby answers that call. That is, the theory provides an explanation.
So the problem-solving ability of a philosophical hypothesis testifies to its explanatory power. Humphreys (1984, 173) explicitly contrasts philosophical explanations with philosophical puzzle solving. Yet even if puzzle solving is understood only in the sense in which conceptual analysis practises it, conceptual analysis can itself be seen as an exercise in explanation giving. An analysis of a concept would help explain why that concept has the extension that it does.
Some philosophers (chiefly Wittgensteinians and ordinary language philosophers) have denied that philosophy provides explanations.
(Wittgenstein wrote that “philosophy really is purely descriptive” [1964, 18], that “we must do away with all explanation, and description alone must take its place” [1953, §109], and that “if one tried to advance the-ses in philosophy, it would never be possible to question them, because everyone would agree to them” [1953, §128].) This comes as no surprise since those philosophers deny that there are any philosophical problems, and they think that the proper business of philosophy consists in pro-viding humdrum reminders about how words in natural languages are ordinarily used. If there are no philosophical problems, there is nothing to explain and no need to theorize. As always, the best way to evaluate such a metaphilosophical view is to examine in detail its application to particular cases. Take as an example Hume’s problem of induction: the problem of showing that our practice of inferring from the observed to the unobserved is reliable. Philosophers of the above stripe have sought to “dissolve” this problem on the ground that it is generated by a failure to understand how terms such as “evidence,” “knows,” “reasonable” and the like are used in everyday contexts. But such attempted dissolutions of the problem of induction have suffered a heavy critical drubbing (Salmon 1957; Skyrms 1966, ch. 2; and Blackburn 1973, ch. 1). To date, these criti-cisms have not been met. Unless debunking treatments of such test cases can be made good, there seems no merit in blanket scepticism about the genuineness of philosophical problems and the point of philosophical
theorizing. Perhaps some philosophical problems are pseudo-problems, but which problems these are needs to be argued for on a case-by-case basis. It cannot be established by an across-the-board dictate.
Given that philosophical hypotheses purport to offer explanations, what kind of explanations do they offer? There are two routes philoso-phers might explore. Philosophiloso-phers might devise explanations that emu-late forms of explanation found outside philosophy, and especially in science. Alternatively, they might strike out on their own and produce a form of explanation peculiar to philosophy.
Taking this second route would be understandable. If only philoso-phy can solve philosophical problems, and those problems are requests for explanations, then perhaps their solutions require a form of expla-nation peculiar to philosophy. A disadvantage with taking this route is that it leaves philosophers to their own devices in answering such ques-tions as: What would make different philosophical explanaques-tions of the same phenomena rival explanations? How should we choose between rivals? What would count as a good or a bad explanation in this sense?
Having resolved to devise a novel form of explanation, one peculiar to philosophy, philosophers cannot draw upon the criteria used in forms of explanation found outside philosophy. The status of this alleged form of explanation is left unclear. It will not be obvious that philosophical hypotheses are genuinely explanatory.
An example of this predicament is given by the “two worlds” inter-pretation of a metaphysical thesis that Kant calls “transcendental ideal-ism” (Strawson 1966). We will not take up the exegetical issue of how accurate or defensible this interpretation is. Our interest here is in its supposed explanatory content. Kant sought to explain how it is possible to have experience of a world of objects in space and time that fall under Newtonian laws of mechanics and gravitation. According to the two worlds interpretation of Kant’s metaphysics, there is a world of things-in-themselves (“noumena”) including our noumenal selves, and there is a world of things-as-appearances (“phenomena”) including our selves as they appear to us. Phenomena are objects in space and time that are acted on by Newtonian laws; noumena are not. We perceive phenomena; we do not perceive noumena. Noumena act on our noumenal selves to produce a phenomenal world. This last claim contains the crucial explanatory claim in the two worlds interpretation. But what kind of explanation does it involve? Noumena do not causally act on our noumenal selves to produce the phenomenal world. Kant is explicit that causal relations hold among only phenomenal objects. It is then utterly mysterious what these noumenal relations are, and so what kind of explanation, if any, Kant is giving.
Given the difficulties facing the ambitious route of devising a pecu-liarly philosophical form of explanation, let’s turn to the route that emu-lates forms of explanation found outside philosophy, and particularly in science or mathematics. By taking this route, we need to address (Q2):
Insofar as a philosophical theory differs from a scientific theory, how can a philosophical theory be genuinely explanatory?