In a recent post we linked to a paper by William Lycan that argues that both dualist and materialist mind-body philosophies are equally unsupported by evidence. As I mentioned, this is surely heartening to Cartesians, who must weary of having their views dismissed as so much nonsense. But is it right to conclude from Lycan’s paper — as his dualist readers are likely to do — that one might as well plump for dualism as materialism? Not so fast. Lycan doesn’t think so, and neither do I.
Lycan rehearses some of the sentiments that incline materialists toward their view. He begins by quoting J.T. Smart:
[S]ensations, states of consciousness,…seem to be the one sort of thing left outside the physicalist picture, and for various reasons I just cannot believe that this can be so…. That everything should be explicable in terms of physics…except the occurrence of sensations seems to me frankly unbelievable….
The above is largely a confession of faith….
Lycan agrees with Smart. But he acknowledges along with Smart that this does not constitute an argument, but rather, “in David Lewis’ famous phrase, an incredulous stare.”
Nevertheless, one would be inclined by parsimony to avoid positing immaterial entities if one can, in particular entities that carry no explanatory water. After all, it certainly appears that brain events are tightly correlated with mental ones.
It is reasonable to think that every mental state or event at least has a corresponding type of brain state or event. The best, because most parsimonious, explanation of those correlations is that the mental states/events just are the “corresponding” brain states/events. (In general: When Xs are invariably accompanied by Ys and you can find nothing to distinguish Xs from Ys, the best explanation is that Xs just are Ys.)
I firmly agree that parsimony or simplicity is a reason for preferring one hypothesis to another. But it is a very posterior reason. That is, not only does it always carry the qualification “other things being equal,” but many, nearly all, other things must be equal before parsimony is called in to break the tie. And no party to the mind-body dispute will deny that dualists have found plenty of features that seem to distinguish mental states/events from neurophysiological ones—even if, as materialists contend, all those differences are ultimately specious. To anyone uncontaminated by neuroscience or materialist philosophizing, the mental does not seem physical in any way at all, much less neurophysiological. The parsimony argument does not even come in the door until it is agreed that we can find nothing to distinguish mental states from neurophysiological ones. And the latter will not be agreed any time soon.
I think Lycan is giving up a little too much territory here; in order to level the field he suggests that one need be “uncontaminated” by neuroscience. I for one, hardly see the extraordinary progress in this area as “contamination”, but rather as a promising march toward the truth — and if dualists must fend off science with a boathook in order to keep their own vessel from springing a leak, that speaks rather poorly of its seaworthiness.
Lycan then questions the strength of the correlation between neural events and mental ones:
More decisively, Smart’s alleged correlations have never materialized. Notice that he must have meant type-correlations; unless one were already presuming token identity, it would have made little sense to say that for every mental token, there is a “corresponding” neurophysiological token. There may be a few type-correlations holding within particular species, but if so they are very few. Whatever is in common as between all human beings who believe that a Frenchman has been assassinated in Trafalgar Square (to take an old example of Dennett’s), that feature could not possibly be characterized in neuroscientific terms; there are no “Frenchman” neurons, nor “assassination” areas of the cerebral cortex; at best the feature would be a complicated set of external psychosemantic relations to Frenchmen, to assassinations, and to Trafalgar Square. (And good luck to the psychosemanticist.)
This is an open, empirical question. Lycan assumes here that even if each brain betokens every semantic entity with some particular syntactical representation (which seems almost certain, to materialists), there is still no general rule of correspondence establishing any particular syntactical representation. But is this necessarily so? While it may well be that each brain, having “wired itself up” in fetal and postnatal development, is syntactically unique, the difference may be analogous to that between languages, in which the details of the tokening-system are not the point. It may well be that all brains obey the same guidelines for bootstrapping a syntactical arrangement into place, and that despite the self-referential uniqueness of each brain’s particular instantiation, the system is still amenable to analysis according to principles of organization that are common to all brains. We may find that, once sufficient technical resources are in hand, all that is needed to “read” a particular brain is to establish a point of entry such as observing a standard set of concepts as they are processed, and work in a well-determined way from there.
The paper continues in this vein. Lycan finds, with varying degrees of plausibility, a loophole for the dualist in every materialist objection (although one he does not consider is that “split” brains, in which the corpus callosum has been severed, appear to host two consciousnesses). But having done so, is he now on the fence? Is he now tempted to abandon materialism? Not at all. The paper is sprinkled with disclaimers like the following (given just after allowing that the immaterial mind may still depend on the material brain, not just for sensory and volitional input/output, but for all its cognitive work):
Here again, the picture is implausible, but only because dualism and Cartesian interaction are implausible in the first place. Subtract those two implausibilities, and the rest of the picture is not bad at all.
Indeed. It does appear that the more we learn, the less and less there is for the immaterial mind to do. It’s kind of a Mind of the Gaps. By the end of Lycan’s paper, we are pretty much down to “providing subjectivity” as the only job the brain itself can’t take care of on its own.
So why isn’t Lycan ready to jump ship, if there is a dualist answer to every materialist objection? I imagine it’s because, although each objection can be met with some intellectual contortion — by casting doubt on the reliability of ordinary causality, or pleading for causal overdetermination of volitional acts — the fact that in order to defend dualism such hoops must be jumped through, again and again, at every turning, makes the whole position seem terribly unlikely. And here is where we can at last invoke the principle that Lycan set aside at the beginning:
I firmly agree that parsimony or simplicity is a reason for preferring one hypothesis to another. But it is a very posterior reason. That is, not only does it always carry the qualification “other things being equal,” but many, nearly all, other things must be equal before parsimony is called in to break the tie.
By the end of this paper Lycan has done everything in his power to see to it that neither side has any evidential advantage; he has meticulously leveled the field. Well then! Ceteris paribus it is. If everything really is equal, we are allowed, at last, to invoke parsimony in order to choose sides.
And from there, only civility prevents me from saying it’s a no-brainer.