Sometimes 'Doctor Who' will just drop a bomb on audiences... and then never mention it again
Are regenerations biological in nature or a form of government control?
Any time the Doctor seems to be in need of extra lives, the Council is there to send him more. We've even seen him return the favor by healing River Song (Alex Kingston). But what kind of evolutionary adaptation would lead to a collective sharing of life force? Perhaps instead, the twelve regeneration limit is a technological advancement imposed by the Time Lord council. This would explain how in "The Deadly Assassin" they are able to barter more regenerations in return for the Master's cooperation. It would also explain why not all Gallifreyans appear to be Time Lord in "The Invasion Of Time." This leads to some uncomfortable questions about the immortal Gallifreyan elite and how much control they exert not only over their own people, but all of time and space.
- Donna Dickens