The soul, the immaterial “breath of life”, was originally thought (I believe) to be where most of our thoughts, feelings, and personality originate. However, a lot of the functions of the brain, like cognitive thoughts, aggressiveness, generosity, attribution of your actions as being self initiated, and happiness have been shown to either have a biological basis or correlates. A lot of these functions overlap with what I would have attributed with being the immaterial soul.
For example, I would have thought that trust would be something that would originate in the soul, however, oxytocin can make someone more trusting. It also seems to play an important part of maternal love and long-term relationships. Morality is also attributed to the soul, but alcohol can inhibit moral actions. I don’t see how alcohol can make it more difficult to be moral, unless there is some biological component of being moral. Perhaps, only the conscience is a part of the soul, but acting on the conscience is either a function of the physical brain or a close collaboration between the soul and the physical brain? Also, attributing an action (such as your hand moving) as being self-initiated versus involuntarily initiated (such as uncontrolled shaking of the hand) seems to rely on subcortical areas and people with schizophrenia (presumably a biological disorder) are unable to correctly attribute their actions to themselves. I would have thought that the soul be able to distinguish actions that it initiated? Or does the soul even responsible for initiating conscious actions?
Are there Christian scholars who propose ideas of the different roles that our biological brain and souls play and how do they interact?
Note 1: This question may challenge your preconceived notions of the soul, but it does not challenge the idea that there might be an immaterial soul. I’m just curious about details of such conjectures; detailed to the extent that they might form testable hypotheses. Some of which will inevitably be wrong, there is nothing wrong with this.
Note 2: While the soul may be immaterial, if it affects the biological brain, then it is at least theoretically possible to study it with science. For example, gravity still remains a black box to us. There are hypotheses (such as the graviton), but we don’t really know. But this has not prevented us from studying the effects of gravity and learning a lot from it. Likewise, behaviorists treated organisms as a black box, but that didn’t prevent them from making a lot of discoveries about learning. I think the possibility of using Science to learn more about the soul is exciting, and you should also :-).