essentially the separation between mortal form and spiritual self

If by 'spiritual self' you mean a feeling (which could be invalid in that it has no objective reality) of individuality, nihil obstat. But I don't think 'spirit' can possibly be a useful word to use for it, as it means too many things, and could lead to the assumption that, since we have 'spiritual' aspects- those aspects not immediately examinable by external physical means, such as our feelings- there must be an object called a spirit, somehow separate from the body, which feels them- the 'ghost in the machine'. It assumes the existence of an observer, separate from the biological workings of the body, which monitors its operations.

If, on the other hand, the potential for self- awareness is simply a property of matter- that it is the appropriate organisation of that matter that makes the matter aware of its existence- there is no separate 'spirit', the ghost IS the operation of the machine.

I really think that words with less historical baggage should be used- perhaps 'awareness' is neutral and descriptive enough?