I had this really odd thought. If you cloned yourself and you have identical memory with the clone, the clone is not you and he/she is not you, that makes the clone unique. What identifies or separates the two? What I'm getting at is this. What is it that makes you and the clone separate, say for example you could switch off and become the clone or vice versa. Is there a unique 'signature' somewhere ? Obviously the thought of 2 people 'connected', would create some sort of problem, you can't see with four eyes sort of thing? Where would you start looking and what for? I know this sounds weird but have a go!