What do we know? For the moment I’ll bracket my Christian faith and consider the state of the problem apart from any divine guidance.
1. Where should we start? Well, at a practical level, we all start with common sense. That is to say, dualism is the doctrine of common sense. Experience presents us with an apparent dichotomy between mind and matter. Mental properties seem to occupy a different domain than sensible properties.
There seems to be a subject/object distinction between mind, body, and the sensible world. It looks like our mind can act on our body, and via our body, act on the world. Likewise, it looks as though the world can act on the body and reach the mind with information from the outside.
Perhaps this is an illusion in one way or another, but that's where we must all take the first step. It may not be where we end up, but that's square one.
2. This, of itself, creates a prima facie presumption in favor of common sense. For any alternative will take common sense as its point of reference and represent a modification of common sense.
Such a presumption does not, of course, mean that common sense is indefeasible. But when, for example, you have so many writers who operate with a presumptive materialism, I, for one, rebel.
3. There are also degrees of modification. One can modify common sense in some respects without overthrowing it altogether.
4. The more radical alternatives modify common sense in the direction of simplicity, by treating dualism as illusory, and reducing it to either materialism or idealism.
5. In terms of method, how we end up depends in no small part on where we begin. If we begin with the mind, then we will likely end up with idealism or some highly refined version of dualism.
If we begin with the body and the senses, then we are more likely to end up with materialism. At the same time, it is ironic that radical empiricism is only a thin door away from idealism.
6. Speaking for myself, I think the mind should enjoy epistemic priority, simply because our knowledge of the mind is immediate, whereas, on either dualism or materialism, our knowledge of the world is mediate. Even if you think the mind is reducible to matter, your evidence for this proposition will still be filtered through the mind. When the mental subject takes the mind as its own object, the mind is the prism through which any reductive explanation must pass.
I therefore think that materialism suffers from a built-in handicap, and frankly, I don’t see how it can ever overcome the burden of proof. It's not just that the onus is on materialism. Rather, materialism can never objectify the mind, to get around it or behind the mind.
7. Simplicity is a fairly tautologous criterion. A theory of the world is only true if it is true to the world. If you knew how simple or complex the world was, then you'd know if a given theory was too simple or too complex to account for the world. But if you already knew that, then you wouldn't need the theory--and if you need the theory, then you don’t know what the world is like. And, of course, it's not just any kind of simplicity which will do, but a simplicity specific to the world--an exact match between the world and its theoretical description.
This is not to say that the law of parsimony is absolutely valueless. Some theories are needlessly complicated because the theorist has a certain ontological commitment, and he sacrifices everything else to harmonize the phenomenon with his ontological commitment.
Likewise, a theory may start out reasonably enough, but as more evidence rolls in, it may require ever more tweaking and retrofitting to keep the theory consistent with the phenomena.
According to common sense, bigger things are made of smaller things. But that raises a regressive question, how small is small? Common sense quickly conducts us, in the words of Leibniz, into the" labyrinth of the continuum." What began so simply ends in the endless labyrinth of infinite divisibility.
8. Another problem with Occam's Razor is that something may be simple or complex in more than one respect. A materialist will say that materialism is simpler than dualism because it has no need to posit abstracta or intelligibles. But an idealist will say that idealism is simpler because it has no need to posit concreta or sensibilia.
Conversely, idealism and materialism are deceptively simple inasmuch as both must account for the illusion of dualism. In addition, materialism must come up with surrogates which do the work of abstracta and intelligibles. And this substitutionary process can be quite cumbersome and indirect.
At one level, idealism collapses the hiatus between appearance and reality by collapsing the subject/object dichotomy. If the whole of what there is is mental, then the whole world is mentally transparent.
But, at another level, idealism must then explain the illusion of an external world. So it repositions the original problem. The world is not so transparent after all.
Again, materialism, at one level, simplifies the subject/object duality. Monism is simpler than dualism, and both the subject and the object of knowledge are now consubstantial.
But that reduction, even if valid, goes no distance towards resolving the underlying epistemic barrier, for the brain still has no direct access to the sensible object. If materialism is true, then whatever we know or think we know of the external world is fed into the brain by means of encrypted information. And sensory enhancements (e.g., microscopes, telescopes, &c.) must still be patched into our primary sensory processing system. So the veil of perception remains firmly in place and opaque. Our mental representation of the world is not a copy, but a sign.
9. There is, I think, an asymmetry between materialism, on the one hand, and idealism or dualism, on the other. Materialism can, I think, be proven false. Indeed, I think it has been proven false. On the other hand, I don’t think that either idealism or dualism can proven true or false--not directly, at least.
For example, Gilbert Ryle, in his classic attack on Cartesian dualism, The Concept of Mind, denied the existence of a mental process on the grounds that it had no analogy to a physical process, which has, or can have, a clear beginning an end; can be continuous or discontinuous; can accelerate or decelerate, and so on.
This does, indeed, point to a deep-seated disanalogy. However, such a disanalogy would serve to confirm the fact that mind and matter occupy different domains. Hence, his counterargument is really a supporting argument for Cartesian dualism.
Of course, materialism has labored long and hard to falsify dualism. At most, though, it only fosters a presumption against dualism. And I'm also of the opinion that dualists like John Foster and H. L. Lewis have more than held their own in this debate.
10. But there's yet another asymmetry between materialism and idealism. Given a choice, materialism is more credible, but idealism is more cogent.
That is to say, I think that, in the debate between materialism and idealism, the latter has always had the better of the argument. But almost no one takes it seriously. We have an irrepressible belief in the existence of the external world.
11. This brings up to the next point: how seriously should be take philosophy? For example, to my knowledge, no one has ever disproved some of Zeno’s paradoxes, despite centuries of sustained effort. Some writers mistakenly believe that Cantorian set theory disposes of the paradoxes, but that is misguided, for the appeal to an actual infinite, which is an abstract object, is no solution to the paradoxes of locomotion.
So what should we do when we're confronted with a logically compelling argument that nonetheless overtaxes the willing suspension of belief? Should we pretend to doubt what we do not and cannot doubt?
Perhaps there is no general answer to this question. Part of what makes an answer credible or incredible goes to our background beliefs. If locomotion is illusory, then you have a fairly radical gap between appearance and reality, and you would need some heavy-duty metaphysical machinery to generate the illusion.
If you're a materialist, the you have less space in your ontology to hide the projection room. But if you're an idealist or dualist, then the illusion is easier to credit because your ontology is already affords a more elastic (idealism) or complex (dualism) space in which to tuck away the equipment.
There's something to be said for Swinburne’s principle of credulity--to have a healthy scepticism of unhealthy scepticism. To suspect that there must be something wrong with Zeno’s paradoxes, even if we can't put our finger on the problem.
Yet secularism is an open invitation to scepticism. From a secular standpoint, the human observeris really, in Berkeley's arresting image, like a scientific oyster, trying to extrapolate to the world at large from the contents of his hard-shelled existence.
In addition, it is scientific realism which particularly posits a veil of perception between the real world of invisible, intangible, infinitesimal fields and particles (or strings) and the common sense view of the sensible world.
12. Another common problem in this debate is the misuse of consequentialist arguments. Indirect realism is criticized on the grounds that if we don’t enjoy direct knowledge of the sensible, but only a direct knowledge of our mental representation, then we may know next to nothing about the sensible inasmuch as our mental representation might bear no resemblance to the sensible, and we can't compare the two. Indirect realism is also criticized on the grounds that it entails some form of dualism.
Likewise, phenomenalism is attacked on the grounds that it conduces to solipsism, while rationalism (a la Plato, Descartes) is criticized on the grounds that introspection affords too slight a database to elaborate a worldview.
Now, the problem with all these criticisms is not that they are inaccurate, but that they confuse a description with a disproof. To show that certain limitations flow from certain positions is not to show that such limitations do not, in fact, exist in the real world. Maybe the truth of the matter is that we do not know nearly as much about the world as we would like.
In fairness, the same argument works in reverse. Locke distinguished between primary and sensory properties. Berkeley took this a step further. Given that our only point of entry to primary properties is via secondary properties, then why not collapse the primary properties into the secondary?
And, indeed, this is logical and economical. But it is hardly a disproof of primary properties. The fact that such a move is possible and elegant doesn't make it true. Perhaps there is more to metaphysics than aesthetics!
Indeed, it's just as logical, just as simple, in its own way, to say that we are subject to sensory impressions because there are sensible objects which project themselves onto our sensory organs. True, color may be subjective. Perhaps the sensible object is colorless. Yet it’s also reasonable to infer that there are some chemical properties in the sensible object which, in turn, stimulate and simulate color in the percipient. In fact, I think that's a more plausible explanation than shearing off the external world entirely, a la Berkeley.
But however persuasive, this is hardly a knockdown argument. As W. T. Stace, in his article, "Science and the Physical World: A Defense of Phenomenalism," has said, we have not got, and never could have, one jot of evidence for believing that the law of causation can be applied outside the realm of perception the law of causation has never been observed to operate outside the series of perceptions, and he can have, therefore, no evidence that it does so. One can only postulate that physical objects cause our perceptions, because one can only perceive the causal laws in our minds and experiences, never in any independent reality unless those same causal laws are presupposed. So our conviction is broader than our foundation--especially on a secular outlook.
Consequentialist objections only disprove the operating premise when the consequences either expose a particular point of incoherence or else undermine the truth-conditions for knowing anything at all.
But to the extent that many theories are both compatible with the evidence and underdetermined by the evidence, to draw attention to the sceptical consequences of a theory does not disprove it or even render it improbable unless the sceptical implications are of a global rather than local variety. Is this a deficiency of a given theory, or deficiency in what we really know--or don’t know?
Left to our own devices, I would affirm "that" there is an external world, but be extremely sceptical about "what" it is like. Moreover, I don’t know that I could put up much of an argument for the existence of an external world. It would be more of case of: I just do believe it, that all! Rather than, this is why you and I ought to believe it.
But, by removing the brackets around my faith, I also believe that revelation can go places where neither reason nor the senses can reach. And in that respect, I do think we have indirect proof for other minds and the sensible world, as well as certain propositions in particular about the same.
This also accounts for our irrepressible belief in other minds and a sensible world. That is owing to natural revelation, which is, in turn, flagged by special revelation.
Howdy there, Laurence.
Thanks for the provocative comments.
You said: "1) I disagree with your opening statement, that you can "bracket" your Christian faith."
I bracket my Christian faith for the sake of argument, in order to expose the consequences of a godless worldview. This is a standard thought-experiment in Christian apologetics.
This doesn't mean that Christian faith is some sort of optional accessory, like mag wheels or whatever. To the contrary, the point of the exercise is to illustrate the necessity of Christian fail by perusing the consequences of its denial to their logical conclusion.
Continuing: " By unbracketing your Christian worldview, you are left with nihilism, and hence no worldview to support your evaluations. The very categories you used to evaluate the various epistemologies have to be based on something. By the very existence of your article, you assumed that words have meaning, and words arranged in logical order produce meaning, and that meaning can be transmitted between individuals. You can never totally unbracket your axioms to evaluate your own axioms, nor anyone else's axioms."
Tsk! Tsk! Now you're allowing for yourself what you deny to me. The very point of my essay was an argument ad impossibile. And the way you try to rebut my opening statement is to mount your own argument ad impossibile!
Yes, there is a paradoxical character to per impossibile counterfactuals, but it's a standard move in logic. See the discussion by Nicky Rescher at: < http://www.utm.edu/research/iep/r/reductio.htm>
Continuing: "(2) It seems you are stuck in a battle of empirical epistemologies. I think your "serious trinitarian theology" blog would appreciate a "serious trinitarian epistemology" -- neo-synthetic foundationalism -- a triune epistemological approach of rationalism, empiricism, and historicism/experience. It seems to me that your article ignores the other two essential foundations for truth: reason and experience. (For example, you'll never be able to evaluate your own mind in a test tube, but through reason and your own experience you are more than warranted in believing that you exist and that other people exist.)"
i) It's true that my essay is one-sided inasmuch as it fails to present much of a positive alternative. However, the deconstructive task is preliminary to the reconstructive task.
ii) Actually, I've written an essay in which I offer a constructive alternative. Due, however, to copyright restrictions, I can't post it before Spring--at the earliest (so my editor informs me).
iii) When you say we're warranted in believing in other minds, is this with or without God in the equation?
iv) Appeal to reason and experience are circular criteria. How does experience warrant belief in other minds unless you can first warrant experience itself? And how do you propose to do that? How does foundationalism justify what beliefs are foundational? Yes, there's a vast literature on this subject, but it resembles a cat chasing its own tail.
v) Dorothy may still be in Kansas, but from inside the dream, isn't she well-warranted in believing that the land of Oz is the real world? Speaking of which, you might wish to read my "Alice in Slumberland."
Hope that clarifies my intentions. You have the next move.