I’d like, as I often do, to connect a review of possible philosophical strategies to an understanding of the history of philosophy, here. I think one value of history in doing philosophy is that it often helps us spot and classify the strategies, and get a kind of global look at their advantages and disadvantages. This all assumes, of course that the task for which the strategies are formulated is one that we still find worth doing, but sometimes even an analysis of this sort of a problem or task long superseded helps develop one’s technique and illuminates current problems to some degree.
OK, enough of preamble. The problem addressed here is quite general, namely how to discover and verify metaphysical truths. I assume that metaphysics is a matter of working out what must be so if we are to think or know about anything at all.
(1) We are ignoring, of course, perceptual knowledge and whatever seems to follow from it in an unsystematic sort of way. That the dog is in the bedroom, there are rabbits, rabbits like to eat lettuce, and so on, all are truths about the world, not metaphysical truths. But perhaps even here we had best be careful. It might be that if I am going to find out what sort of sleeping arrangements rabbits prefer, there must be rabbits first. That sort of thing we are not going to count as metaphysical. Why not? For now I won’t worry about it, but it bears some thought.
(2) The start of metaphysical (philosophical?) investigation seems suggested by the observation that we might establish something to be true by establishing its contradictory to be inconsistent with itself. That means the contradictory must logically entail contradictory statements. The strategy seems sound without question, and at first it might have seemed to be quite fruitful (Zeno and Parmenides), but philosophers discovered fairly quickly that (a) you had to be careful that you were working with a genuine contradictory and not just a contrary of the view you set out to refute, (b) you had to be careful that you really did get contradictory conclusions from your argument, not just apparent absurdities, which someone could embrace without contradicting themselves, however silly they might appear to an audience sympathetic to our point of view. So this made logic a most important part of philosophy. (c) As everyone picked up the technique it turned out that any position at all could be made to look absurd if one attended to the audience, since the more remote consequences of a position always included things that people were not accustomed to think about that looked, at first blush, quite likely to be wrong. As a result, metaphysics became a matter of defending one’s views from the charge of absurdity, by arguing that no real contradiction was to be found in them, but only consequences that looked, to the uninitiated and thoughtless, the ignorant many, absurd, though in fact they were true. Moreover, a great deal was perceived to hang on the interpretation of basic little words and ideas, so that the analytic approach to philosophy, worrying about fine distinctions and quite fundamental and apparently obvious things, became characteristic of philosophy. This of course, inspires unseemly mirth in philosophy’s detractors. All of this had happened by the time Plato was writing. The outcome seems to be this: that the method only gets us somewhere in logic and mathematics, and while that is certainly not something to sneeze at, especially given developments in mathematics, it isn’t metaphysics. The fundamental structure of reality which makes thought and knowledge about it possible remained obscure, though all sorts of hypotheses were generated and tested out using this technique. Nonetheless, the technique continued to be used and trusted (at least in the hands of the right people), no doubt because nothing else offered itself. So, for instance, its use in Christian theology (applications of discussions of substance and essence, and their relation to individuals, to the doctrine of the Trinity and the Dual Nature of Christ, for instance) led to the preservation of the Ancient tradition of logic and epistemological/metaphysical reflection within the matrix of the theological curriculum through the Middles Ages.
(d) The natural move, faced with the apparent failure of this technique, was to try to establish a little more than non-contradiction as the universally accepted criterion from which one could begin one’s logical investigations of the world. What was needed was a set of self-evident axioms (as Aristotle observed). But what is to provide such axioms? (i) We could go with the opinions shared by everyone, but that rather quickly led to restriction of our assumptions to the things we know through perceptual knowledge, assuming that we stayed away from Skeptics, who would give us reason to be uncertain about those things, too. So we might restrict it to opinions held by the wise and knowledgeable, except that that was question-begging, of course, since we first have to decide who is wise. It might be a good idea to consider the opinions of those heretofore regarded as wise, as Aristotle notes, but that is about as far as we can go, and it is not far enough, by a long shot, to establish dialectical metaphysical argument on a sound basis.
(d)(ii) So we might reflect on how things are known, taking a look at our perceptual and common sense knowledge of such matters, and two theories quickly emerged. (Two, not one, unfortunately.) First, it might be that somehow direct perception, without any causal mechanism that might support the possibility of error, provides knowledge. That, it might seem to us, is how sense perception works. But of course, it isn’t. Upon reflection, we find that sense perception of any particular sort we wish to investigate involves a mechanism, and therefore is not really direct (we only ignore the mechanism most of the time, unless we have some clue that it really is malfunctioning in the current environment), and cannot be relied on except under the right circumstances. That spoils everything, of course, since now we have to establish the circumstances are right first, and the Skeptic about the sense has quite enough to work with at this point to throw it all into doubt. So, perhaps
(d)(iia) direct perception is something rather special, in which one knows another thing without depending on a causal mechanism. That would seem to drive us toward the notion that self-knowledge must underlie our metaphysical knowledge, but that self-knowledge is immediate at all (Hume), or that it can lead to any substantive conclusion beyond “There I am!” (critics of Descartes) is something that can only be established through metaphysical reflection, so we seem to be begging the question, again. Nonetheless, this was the standard Platonist line, making the Forms something recollected or found within the soul, and dominated Western thought for a millennium or two. All sorts of fancy moves were made to defend it, revolving around what the self is that is to be known—if my self is identical to the One, from which the Forms and Soul eventually evolves, through an internal self-recognition of some kind, then we can make it work, or if my self is reason itself, which is self-knowledge itself, knowing all things through knowledge of itself (through dialectic, a development internal to reason), then it can work. This strategy is still at play in the work of such thinkers as Thomas Nagel.
(d) (iib) The Empiricist line, which holds to a non-identity, causal theory of perception and knowledge, and tries to argue that somehow it can be made self-evident that the world must resemble our directly known perceptual images of it. This looks impossible to establish by arguing from the nature of the Reality known, without falling into strategy (iia) and Idealism, and so the Empiricist argues from the nature of the knower and the knowing, and proposes that all we ever really know or talk about or refer to in speaking of the world, is our directly known perceptual images. This, of course, leads to a different sort of Idealism, but Idealism all the same, and the strategy is absorbed into post-Kantian Idealism.
(3) So we have an impasse, or embrace idealism in some form. But we might try something else if we reject the effort to come up with an alliance here between epistemology and metaphysics, and try to do epistemology from a naturalistic point of view, just another science, not as a metaphysical discipline, and see what we get. What we get is sometimes dubbed “externalism,” which means we do not proceed simply internally, looking for a justification for our supposed knowledge that has metaphysical clout, and so involves metaphysically necessary truths that cannot be denied (not because they are logically necessary or true in virtue of word meanings), because without them all contact with the world is impossible. Rather we ask just what, empirically, in our experience, we have in the way of knowledge, and we observe, of course (and tip our hats to Kant for this), that the world contains beings like ourselves who are capable of true beliefs, and and form such beliefs reliably in the situations in which they have evolved. “Reliably” does not mean that these creatures see the underlying reasons why these things must be true, or understand and verify their own perceptual and thinking processes, but only that, as it happens, their beliefs are quite likely to be true in the circumstances in which they form them, and this contributes, of course, to their survival and reproductive capacity in those circumstances. The penalty of getting it wrong is not philosophical shame, but extinction. And it does not have to be got right all the time, only most of the time when it counts. And their beliefs do not have to involve translatability into talk about the most fundamental processes of nature, and so innate knowledge of such stuff, but only whatever is necessary to guide their behavior rationally if those beliefs are true. If we regard knowledge this way, then how does it affect the project of acquiring knowledge through metaphysical dialectic?
Well, it would seem to some that such knowledge is quite compatible with their being no metaphysical knowledge to be acquired at all. We would have to be able to work out, perhaps: (a) How or why it is that our cognitive capacities and strategies work, insofar as they do. But that requires, not metaphysics, but another level of science. We have to figure out how the eyes work, how the brain works, and so on. (b) How it is that mathematical and logical knowledge is to be understood in this framework. (c) Some more or less silly problems about whether the Skepticism developed in response to the metaphysical program of epistemology should be retained as true, or dumped overboard with Platonism, Rationalism, and Empiricism. (d) How it is that a naturalistic scientific approach might be developed to get at the phenomena of subjectivity, qualia and sense data, and the like (I’m thinking of Dennett).
What the anti-metaphysician would apparently like to embrace here would approach problem (d) most directly. She would like to say, developing Kant’s insights, that metaphysics happens because we look for metaphysical explanations of knowledge parallel to the theological explanation why there is any world in the first place. We start with comprehensible enough theories about how we know this or that, or how this or that got here, or how it is this or that comes to appear in a certain way to us, always depending on all sort of empirically given background information within which one or another causal mechanism is able to do its work, realizing a cognition-machine in nature (Functionalist explanation–a skeptic about this strategy would regard this not as realization of a the machine, but as a more or less inadequate imitation of it, and many Platonists might take it as both, of course). Then we see that we can progressively improve our picture, gaining a deeper analytical understanding what is required to constitute such a machine, and a deeper understanding how the causal processes realizing these requirements do so within the environment in which they operate. Indeed, the improvements from what just everyone can see and what the perceptual psychologist, say, understands, are immense. So we begin to imagine repeatedly making such advances, until we are done, and have hit how things really are, and there is nothing more to know. (How we would know we had gotten there, I have no idea, unless we choose to isolate a scientific account from more fundamental levels of analysis explaining why the laws of the applicable theory are obeyed (or appear to be obeyed). So we can just stop at chemistry, and view any impact from atomic physics as expressing itself in a kind of Platonic material resistance (as in the Timaeus) to perfect Formation in accord with the Forms of Chemistry.) We might then ask how we know this, if we are in fact done, and immediately we have doubts if it is just a matter of explaining as best we can all the “observed” facts. All sorts of problems here, of course, which is why skepticism is so troublesome. So we suppose this must be a place that can be got to, though we haven’t done this yet, dialectically, that somehow it is the only possible way the knowable world could be . . . But we have abandoned science and knowledge at this point, and are engaged in mere fantasizing.
How does this get at problem (d)? Well, we move from why things appear this way or that to this sort of being under those conditions to why things appear, at all, to anything, postulating a pure subject and pure object and then fussing endlessly (of course) over how they ever came to be in association with one another. The answer is that they were in association with one another from the beginning, that is, from the beginning, a naturalistic explanation of naturalistic phenomena of appearances (why Judy appears as a pretty girl to Sam, but not to Peter), which always presuppose a background within which the causal mechanism produces the result, and some facts of the case (not necessarily regarding Judy’s prettiness, but something true about Judy to which Same and Peter respond). The only way we get to consider the subjective and objective as such is by starting here at the beginning, where they are inextricably combined. (An exploration of this inextricability, which has a lot of dimensions, might be launched to support this analysis of the sources of metaphysical thought). In fact they are but “moments” of a “single entity” which is neither subjective nor objective (nor monistically neutral), the “experienced world,” let us say. The world never occurs in our experience save as experienced (there’s a good round metaphysical conclusion for you!), and experience never occurs save as the experience of some being experiencing a world (a real world? if you insist, but the specification sounds dangerously adventurous–of course it isn’t imaginary or fake or merely subjective, either). But if we undertook to speak only of those things we know something about, we wouldn’t talk about this stuff at all, or perhaps the world at all, but only about stuff found in the world. It’s not exactly that nothing at all can be said about the world, it’s just that it is all pretty trivial, and the minute it begins to sound interesting, you’ve no doubt misunderstood.