Discounting the indication of sneakiness, which looks like it would change the probability if properly taken into account: 65% I wouldn't out of hand dismiss the possibility that parts of the physical body other than neurons in the brain are involved. For instance I wouldn't be terribly surprised if sub-vocalization of verbal thoughts played an important (albeit probably not irreplaceable) role. Confidence that no such thing as a metaphysical soul is involved: 99.9%