Dualism in a World of Darkness
So there you are, storytelling a twisted tale of modern horror about a coterie of vampires, when an odd ability crops up. One of your players has focused on controlling people so much with the Dominate Discipline that she can now enter other people's bodies, taking them over as if they were her own.
So we know that the 'soul' - that is, the mobile part of the mind, the non-brain part of the mind, has just shifted over into a new body. One might expect the experience to be quite harrowing, for the vampire to collapse like a newly born deer or a stroke victim, and later slowly learn how to walk and speak. But apparently it's quite easy; the vampire's mind (or soul) steps into the new body like a comfortable suit. We can only conclude that all the muscle memory is part of the body - and where else could it reside except the brain? So the brain allows a translation of the soul and the soul just does the general work. So while dyspraxia is about clumsiness in thought and clumsiness in the body, a dyspraxic vampire should, in theory, be able to wander into the body of a dextrous athlete and become dextrous.
Attributes
This brings us to the Attributes of the Storytelling system. Strength and Appearance are obviously facets of the body, while Intelligence and Wits must be facets of the mind. What about Perception? That's equal parts body (good eye-sight and hearing) and mind (noticing details - or is that the Alertness Skill?). We now know which original Attributes the Vampire can use and which must come from the body.
Talents.
Talents present more questions. Empathy is about the soul, Athletics...a property of the body? So a vampire possessing an athlete has a good knowledge of how to throw a discus and pole-vault? And what about the Brawl Skill? If muscle memory is part of the body then it is a facet of the body, and one really can pick up kick-ass moves by possessing people, and lose the ability to fight by possessing a pacifist. But isn't Brawl meant to be all about the training? The physical aspects of brawling are already covered under the Physical Attributes; so shouldn't the Talent be all about know-how? It's where to place one's feet, how to dodge and the general willingness to cause serious damage to someone - something that takes a while to learn, and learning is a mental thing.
Then there's Subterfuge - normally we might be tempted to say that it's mental, but again - if muscle memory is a part of the brain then perhaps the twitches, giggles or habits of looking which can give away a liar are a part of the body. So the Talents list has to be split along lines of those which are physical, those which are mental and those which fall half-way down the middle (such as Brawl and possibly Subterfuge).
More Abilities
Skills and Knowledges seem much more like mental things, so that's a little easier. Still, we've been left with a few things which are half-and-half. How many Mêlée dots can the vampire use? Should we take an average? The book holds no suggestions on the matter.
Philosophers as DMs
Now admittedly, I may be overanalysing things here. Yet it's interesting that a cursory glance at an RPG spell provides a more in-depth problem than many currently in Philosophy of Mind. It's also odd to me that the questions raised by the very prospect of a soul are so pressing for any substance dualists yet so unheard of in the Philosophy department.
Perhaps Philosophers should play more D&D.