okay, i'll be the bigot who comes back with the idea of soul. (i seem to be taking both sides of the argument...)
i've done a bit of study on the traditional idea of 'body spirit and soul', and this is what i think: body, is obvious, the physical, fleshly, material bit. Spirit is like the life-force, the breath, the heartbeat. Soul is the consciousness, heart, the will. Technically, only humans have soul... so only humans have consciousness. but we transpose our consciousness onto our pets because we form emotional links with them, as fellow living creatures... (i suppose this means dogs have spirits, but im not very sure about this...)