The Wormhole wrote:
Do we honestly know enough about the Doctor's past to say they might not be past incarnations? He is a Time Lord with a boatload of secrets after all.
Well, in The Five Doctors when the Fifth and First Doctors first meet.
First: "Ah, so there are five of me now."
Pretty sure the Doctor doesn't lie to or keep secrets from himself.
Were I the Doctor, myself would be the first person I'd keep secrets from.