In the episode Journey to the Centre of the TARDIS
Goes through the rift to warn
Himself of the impending disaster and to tell himself to push the button
How can this even possible without destroying the fabric of space time? Or creating a paradox, or creating a time loop? For example, this paradox loop is created:
Because he pushed the button he does not need to go back in time to warn himself. Because he does not warn himself he does not push the button. So it does explode again, and then gets stuck in a loop forever, alternating between pushing and not pushing the button.
As far as I am aware, its never happened before, and he has only ever talked to
Other versions of himself, never the same incarnation