What are modern Christian views of the soul?

It is clearly true that chemicals and physical alterations of the brain can affect how we think and feel. So -- assuming we understand the "soul" to be what is or holds a person's thoughts, feelings, and personality -- any theory that says that the soul is completely separate from the physical body can't be right. On the other hand, the theory that our thoughts and feelings can be completely understood in terms of biochemical and electric activity in the brain is not substantiated by evidence, but is an article of faith by materialists. No one CAN completely explain thoughts, etc in biochemical terms. They insist that someday science will advance to the point where we can. Maybe, but "I believe this will someday be proven to be true based on unprovable dogmas that I believe because I find them emotionally satisfying" is a long way from scientific proof.

People sometimes discuss this as modern science challenging an ancient Bible teaching. But a little thought will show that "modern science" has nothing to do with it. Oh sure, we know a lot more about the chemistry of the brain today then people did at the time the Bible was written. But this doesn't address the fundamental question. People in ancient times were well aware that chemicals and physical damage could affect the personality. The people who wrote the Bible knew that alcohol could affect someone's behavior. They knew that bashing in someone's head could affect his behavior. But they still talked about the soul as something distinct from the body. So it's not a new issue.

You ask for a view from Christian scholars, so here's one (not mine):

In "Cosmos, Creator, and Human Destiny", Dave Hunt argues that the difference between humans and lower animals is in the brain, but that the brain is just matter, and:

as we will continue to remind readers, matter cannot think

(no basis, evidence, qualification, explanation or research is offered for this assertion, note)

Further, that there is a non-physical intangible element responsible for our thought, distinct from (but related to) the physical matter of the brain, which communicates instantaneously between the the physical universe and the non-evidenced soul existence. This then facilitates eternal existence by outliving physical existence. This non-physical form is then responsible for our thought, emotion, and morality. IIRC, physical/chemical damage is then supposed to interfere with this communication.

Indeed, in his attempt to play down evolution, a lot of emphasis is placed on the difference between man and "lower animals" (which he repeats many times, to draw a very thick line between humans and anything else), which is problematic:

• a lot of higher primates are very communicative, and have successfully used things like sign language and similar communication techniques (oddly, not too disimilar to things like Makaton, commonly used by speech-impaired children, at least here in the UK)
• a lot of animals show things like reasoning (problem solving, etc) and empathy (the rats infamously releasing their trapped cage-mates, etc); if that isn't "thinking" I'm not sure what is

Frankly, I'm not sold on any significant difference between how human brains work, versus that of any other animals - other than we've developed it further, as our primary means of survival. I also think the Dave Hunt work here is very sloppy, in terms of going to great lengths to seek any minor gap in evolutionary theory, while failing to offer even one iota of reasoning for the arguments so strongly asserted. From the author's perspective it makes sense: not presenting such means there is nothing for his critics to pull apart. In my opinion it does not make for a strong case, and as such is representative of most of the other views on a soul that attempt to fit themselves into biology.

Fundamentally, there is a problem: there is no actual scientific justification for even speculating at the existence of a non-physical soul, so trying to find scientifically valid explanations for something that isn't even defined is.... problematic at best. Equally, any purely philosophical proposals designed to fit in with current neurobiological knowledge run a risk of "soul of the gaps" (if you will).

EDIT FROM THE COMMENT BELOW

Reading trough systematic theology books, I found that Christians hold that the human has two are three parts. The two parts view says that the human is body (material) and soul(immaterial), the three parts folks hold the position that human are body(material), soul(feeling), conscience(image of God, moral center).

Here are two links to books chapters on Google :

Lecture in Systematic Theology by Henry C. Thiessen

Systematic Theology by Wayne Grundem