The subject of souls are something people often mistake as something found in a religious context and not so much throughout a philosophical or even neurobiological one (which neurobiology in respect to the soul has made mistakes in its own right). In other words I just think discussions about the soul can take place between two irreligious people merely discussing the relationship between the mind and the brain.
Philosophers who have done work in this field such as Stewart Goetz, Charles Taliaferro, Richard Swinburne, J.P. Moreland, David Chalmers, Alvin Plantinga, Jerome Schaffer and many others are of interesting consideration in terms of literature.
Norman Geisler writes that “[m]ost religions, and Christianity in particular, assume that humans are spiritual beings, capable of communing with God, who is the supreme spiritual being, and of surviving the dissolution of their bodies in death” . However, materialistic views of nature see this religious optimism of “divine relationship” as “ill-conceived.”
I don’t like to think of humans as “at-bottom” materialistic substances which can be reduced to their most basic and general components. Thinking that the mind is separate from the brain (contrary to materialism) is the best way of viewing the soul. In other words, “[m]ind and body causally act upon one another in that mental events may cause bodily events, and vice versa” 
This, in its qualitative and exemplified form, can be found in Goetz’s section on Mind/Interaction:
…on certain occasions, we have reasons for performing incompatible actions. Because we cannot perform both actions, we must make a choice to do one or the other (or neither), and, whichever choice we make, we make that choice for a reason or purpose, where that reason provides an ultimate and irreducible teleological explanation of that choice (thus undetermined choices are not inexplicable choices). The making of a choice is a mental event that occurs in a soul, and either it or some other mental event associated with it (e.g. an intention to act) directly causally produces an effect event in that soul’s physical body. 
Thus, Goetz finishes by saying that “there is mental-to-physical causation, and its occurrence is ultimately and irreducibly explained teleologically, by appeal to the reason that explains the making of the choice” .
Theoretical physicist Paul Davies (himself not a religious believer) echoes this in his book God and the New Physics . He begins his discussion by pondering a question:
…I know of no religion that does not teach that God is a mind. In the Christian religion God is omniscient – infinitely knowledgable [ … ] There can be no mind greater than God’s, for God is the supreme being.
But what is mind? 
Davies draws an analogy of mental events taking place by some alarm of a sound: “‘What is that sound? Has something broken? Should I investigate? Yes’ – and the brain cells activate. But although the mental description thus far is consistent with the physical, there is a crucial element that does not tie in; namely, the fact that you decide to investigate the noise [ … ] Where is there room in the deterministic predictive laws of electrical circuitry for free will?” .
The soul then is sometimes understood interchangeably as “the self”, or the mind. I think this interpretation of the soul as an immaterial substance interacting causally with the brain is the most consistent in line with philosophical research.
-  N. Geisler, Introduction to Philosophy (Baker: 1980) p. 180
-  Geisler, 186
-  Stewart Goetz and Charles Taliaferro, A Brief History of the Soul (Wiley-Blackwell: 2011) p. 157
-  Goetz, 157
-  Paul Davies, God and the New Physics (Simon & Schuster: 1983)
-  Davies, 72
-  Davies, 74