May 2, 2017


The Soul: Not Dead Yet (Patrick Lee and Robert P. George, May 2nd, 2017, Public Discourse)

The claim that genetics has helped "kill off" the idea of the soul usually rests on the notion that the actions of DNA molecules are sufficient to explain the events occurring in the larger-level entities of which they are parts--namely, the organisms, human beings included. The idea is that the characteristics of organisms are sufficiently explained by the properties of and the spatial relations among their microphysical components. And so (on this view) there is no need to appeal to the causal powers of the organism as a whole to account for what occurs in it. Therefore, genetics could assist in a general program to explain away higher-level properties such as nutrition, growth, perception, and thought, by reference to the properties of the microphysical components.

However, while bold promissory notes to provide such explanations have been given, actual payment--in the form of adequate explanations--has never been provided. Moreover, if such a reduction could succeed, whole animals could not then actually be single entities--"composite substances," to borrow Aristotelian language--but mere aggregates of microphysical entities. This reduction wouldn't just negate the idea of a soul but also the idea that we are both animals and persons.

Of course, many complex objects are mere aggregates. Many of the things we might view as unitary objects actually only produce effects that can be fully explained by the properties and interrelations of their constituents. For example, as Trenton Merricks points out in his Objects and Persons, what a baseball does can be fully explained by the concerted actions of its constituents. A baseball shatters a window, not in virtue of any property of the baseball as a whole, but in virtue of the properties and spatial relations of microphysical entities it contains. However, other composite objects, particularly organisms, have causal powers belonging to the complex substance as a whole. When a human being walks to the refrigerator to retrieve food for a meal, this is a behavior performed by the organism in virtue of conscious properties--properties that belong to the complex substance as a whole. She walks to the kitchen and not to the living room because of her memory and belief that that's where the food is. Such a conscious belief can scarcely be conceived of as inhering in this or that particle, or as a structural relation of the particles to each other. Rather, it inheres in the organism as a whole and guides the behavior of that organism as a whole. Thus, the unity and causal properties of the organism as a whole are irreducible to the powers and relations of the microphysical entities it contains as parts.

Nor has neuroscience helped "all but kill off" the concept of a soul. It could do so only if it showed how thought could be reduced to neuro-processes. But many have pointed out the insuperable difficulties for such a reduction. Any argument advanced to support such a feat would logically undermine itself. For the point of the reduction would be to show that one's thoughts are fully explained by the interactions of electrochemical processes operating according to physical, not necessarily logical, laws. But if one's thought--including the reductionist's argument itself--rests on such non-rational causes, it is undermined, since beliefs that are determined by non-rational causes, rather than reasons, are thereby made suspect. If my thoughts are merely the result of the electrochemical processes in my brain, then they are non-rational.

Of course, a proponent of the reduction might object that there can be more than one explanation for an event, and so the thought's explanation on one level (neurons firing) does not preclude its simultaneous explanation on another level as well (logic). And thus, he might say, thoughts are identical with or fully determined by brain processes, but these processes can be explained in both physical and logical terms. Just as the same material event can be explained both by biology and by physics, and the two explanations are compatible, so here (it might be argued), one can give both an explanation by reference to logical laws and by reference to brain processes and their wholly materially determined interactions.

The proposed reduction of thought to neurochemical processes could succeed, however, only if the actions of the neural components, operating according to physical laws, determine the reasoning processes--that is, determine which conclusions one draws in an argument. On a reductive view of mental events, the premises (or the acts of accepting the premises) have the causal powers they do only in virtue of their physical properties, and so the logical laws--the relations among contents of thought just as such--will be utterly irrelevant. Thus, if thoughts are just neuro-processes, governed by physical laws, then the laws of logic are dispensable, and the physical antecedents of a thought (such as a conclusion) determine it regardless of the contents of those antecedents. But this renders the argument by which one defends the attempted reduction unworthy of acceptance. Thus, thought cannot be adequately explained by neuroscience alone.

Posted by at May 2, 2017 6:32 AM