So Brian and I have started watching the American remake of the BBC programme ‘Life on Mars’. In it, Lisa Bonet plays Maya Daniels, the modern-day girlfriend of Sam Tyler, a detective who has mysteriously traveled back in time to 1973.

So my question is: if Lisa Bonet is ‘Maya Daniels’ in Sam Tyler’s world, does that mean he lives in an alternate dimension, where the Cosby Show never existed? And if so, does Obama still get to be president there?

Take that, Bishop Berkeley.