Here’s an argument for the soul from the presumption of the possibility of rational thought. If one is a physical determinist along with a materialist with respect to the human mind, then one is admitting to cognitive fatalism. Every thought, and every belief, if it is determined, cannot aspire to being a rational belief in the sense that it represents a fair reflection on some proposition, and then a free choice with respect to whether to believe it or not. Instead, every belief, no matter how certain it seems to the cognizer, is simply a matter of physical disposition itself determined not by anything rational, but rather by the brute force of material order. Nobody can in any sense be responsible for any one of their beliefs – since, of course, no belief would be chosen in any sense. Curiously no belief could be justified either, since epistemic justification would fall into vicious circularity if it admitted of itself that it was determined by something other than the metaphysical truth.
Alternatively, is one is a materialist without being a determinist, then somebody might think that our beliefs being randomely generated would allow our beliefs or our overall belief set to be ‘rational’. However, here, again, even a coherentist will fall prey to the accusation that her perceived coherence is itself a belief resulting from physical disposition.
Thus, the only way in which we can have beliefs which are ‘rational’, by which I mean reflexively considered and freely believed by an act of the intellect, is if we have some faculty which is at once rational and also free in the Libertarian sense. However, this is what people who believe in the soul mean by “the soul” (at least minimally).
- The only way in which we can have beliefs which are ‘rational’ is if the soul exists.
- We do have beliefs which are rational.
- Therefore, the soul exists.
However, if the soul exists, then materialism is wrong. Therefore we might extend this argument to the following, this time tailored for epistemologists:
- The only way in which we can have justified beliefs is if we can have rational beliefs.
- rational beliefs are possible only if the soul exists.
- Therefore, the only way we can have justified beliefs is if the soul exists.
- We can have justified beliefs.
- If the soul exists then materialism is wrong.
- The soul does exist (from 3&4 conditional elimination).
- Therefore, Materialism is wrong (from 5&6 conditional elimination).