The fact that you and I are alive is against stupendous odds. One day we will die, and that's sad, but there are people who will never die because they were never born. We're the lucky ones, we get to die.

…discrimination on the basis of sex, it has been said, is the last universally accepted form of discrimination, practiced without secrecy or pretence even in those liberal circles that have long prided themselves on their freedom from prejudice against racial minorities.

We are under an existential threat now as humankind. Even a simple two-cell yeast has a survival instinct and evolves fast enough to try and survive. I don't understand why humans who are supposed to be these very complex creatures can see that we're heading towards a very, very dangerous future which could be irreversible, and why we're not doing absolutely everything possible now.

It's difficult to describe to people who aren't curious, just what curiosity is. Imagine explaining to a robot or a computer what curiosity is! For those of us who experience it however, it's almost a primal-pull.

A lot of people assume that I would choose not to have bipolar disorder; but I'm grateful for it. I wouldn't trade it for anything in the world, because I feel like all the ups and downs have formed who I am, and made be braver, tougher… more creative and more capable.

One of the great ironies of a company like Meta, where I worked, is that well over 90% of its users are outside the US, yet well over 90% of the bandwidth among decision-makers is focused on what's happening in America. In the end, that just doesn't make sense.

Think about how that feels when you're told that for this essential skill that is part of the astronaut job, you're not needed. It's as if they were saying, 'You don't bring anything essential and we won't miss you.' That encouragement pushed me to show up to spacewalking meetings I wasn't initially invited to.

We are the only species who have taken control of their evolution. We are animals who – one day – had an idea to become better. Billions of us have worked to make ourselves better – that's why we created the concept of God, an entity that is everywhere, that is powerful, that is the master of everything, that gives us a unique model for our society. Now we know God doesn't exist, and so we know we are better than that notion of God.

An actor who isn't acting becomes a sort of non-person. If you're not acting, what are you?

Over 70% of the labour force in sub-Saharan Africa is involved in agriculture. This means the sector forms a lynch-pin of society.

Read a lot. Never accept current standards. Always improve yourself. And remember, you always meet twice in life.

If the role of government is, as Thomas Hobbes put it, to stop life being nasty brutish and short because humans unregulated are at each other's throats, then government has to step up to that plate now and start rethinking what it can do to ensure cohesion in societies where you will always have disagreement.