The Mirrorball Man 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.
No we don't. He's said some things about his previous incarnations, but it's been said that the Doctor lies quite a lot.
The problem with that is that the Timelords themselves seem pretty clear which Doctor is the first incarnation, now you could argue that they are lying but who to
? They reveal this information while talking to each other.