Mind & body

Okay, let’s wrap up our miniseries on Exbeliever’s argument against dualism. In objection to dualism, he mentioned some case-studies in which brain injuries or brain disorders resulted in personality disorders.

He then took this to be compelling evidence that mental states are reducible to brain states.

By way of reply:

i) This is hardly a new objection to dualism. We have always known that changes in the body can impact the mind. Why does the Bible warn against the dangers of intoxication?

Were Bible writers unaware of the fact that when the bodies of boys and girls undergo a certain stage of development, this is accompanied by certain psychological changes as well, viz., sexual attraction?

Were Bible writers unaware of the fact that a bonk on the head can altar one's personality?

Modern medical science, with its diagnostic techniques and superior understanding of how the body works, can chart these correlations with greater detail and specificity, but the interrelation between mind and body is a commonplace of human observation.

ii) According to the interactionist model of dualism, the mind acquires its knowledge of the sensible world through the senses. As a result, it forms many or most of its beliefs about the sensible world via the senses. And, of course, we act on what we believe.

Among other things, the brain is the central processing system for sensory processing. If, for whatever reason, brain function is impaired, whether temporarily or permanently, then that will alter our perception of the world. It will altar what we believe about the world. And that, in turn, will also affect how we feel about the world—affecting our moods or emotional life, since we are reacting to what we believe.

If I mistake a garden hose for a rattlesnake, I will behave accordingly. To the extent, then, that the soul’s awareness of reality is conditioned by the conduit of the nervous system, it is hardly surprising if a brain malfunction has an influence on what we believe and how we behave.

A man who is hallucinating under the influence of a psychedelic drug will have an altered perception of reality. And if seeing is believing, a misperception has doxastic consequences.

iii) This can have a religious dimension as well, for natural revelation is a source for our knowledge of God. But if, due to brain malfunction, we misperceive the world, we will also be a risk of misperceiving some of the evidence for God’s existence.

iv) None of this would come as a surprise to the writers of Scripture. For example, you have in Scripture a category of visionary revelation.

Phenomenalogically speaking, the mode of visionary revelation is akin to a rapture or ecstasy or out-of-body experience.

It was understood, way back then, that as long as consciousness is filtered through the senses, the percipient is insensible to the supersensible range of experience inasmuch as his attention is preoccupied with the sensible world.

In order to perceive the spiritual realm, the percipient must undergo an altered state of consciousness in which his sensory awareness is blocked.

Fasting and music were also used to enhance one’s state of spiritual receptivity.

iv) Some conscious states are dependent on the brain, not because they are constituted by the brain, but because their conceptual content is supply by external data.

Consciousness is, among other things, consciousness of something. So something must supply the object of thought, whether that comes from an external stimulus or memory or imagination or revelation.

iv) Then there’s the matter of our physiological appetites which, in turn, have a dispositive effect on temperament. Hormones are a natural example.

Because, once again, the soul perceives the world in much the same way as a man in a VR suit perceives his virtual environment, the suit is just as important as the program—hardware and software alike.

Finally, exbeliever poses this question:

“How can two consciousnesses (or "souls" for many theists) be explained within the same person? Is there a devil in one hemisphere and an angel in the other? Does the spiritual consciousness of one hemisphere go to heaven and the other to hell (assuming religious traditions believing in reward and punishment)?”

It didn’t take him long to forget that Christians believe in the phenomenon of possession. So that is certainly one way, though not necessarily the only way, we can account for multiple personalities.