Evolution has ensured that our brains just aren't equipped to visualise 11 dimensions directly. However, from a purely mathematical point of view it's just as easy to think in 11 dimensions, as it is to think in three or four.

There could be whole antiworlds and antipeople made out of antiparticles. However, if you ever meet your antiself, don't shake hands! You would both vanish in a great flash of light.

Do you ever wonder how much deeper the ocean would be without sponges?

We are in danger of destroying ourselves by our greed and stupidity. We cannot remain looking inwards at ourselves on a small and increasingly polluted and overcrowded planet.

Think of our DNA. In the last million years, our DNA hasn't changed at all. It's really much the same as it was in the jungle, a million, two millions years ago. But in the last 200 years, our destructive capacities have increased many, many millions of times over. Why don't we see intelligent signals from outer space? Because in all likelihood, once the civilization reaches the point our civilization has reached, it destroys itself.

The laws of science do not distinguish between the past and the future.

Mankind's greatest achievements have come about by talking and its greatest failures by not talking. It doesn’t have to be like this.