Post-human intelligence will develop hypercomputers with the processing power to simulate living things - even entire worlds. Perhaps advanced beings could use hypercomputers to surpass the best 'special effects' in movies or computer games so vastly that they could simulate a world, fully, as complex as the one we perceive ourselves to be in.

As regards my own 'philosophy,' I continue to be inspired by the music, liturgy and architectural tradition of the Anglican Church in which I was brought up. No one can fail to be uplifted by great cathedrals - such as that at Ely, near my home in Cambridge.

Some of the 'aha' insights that scientists strive for may have to await the emergence of post-human intellects.

To most people in the U.K., indeed throughout Western Europe, space exploration is primarily perceived as 'what NASA does'. This perception is - in many respects - a valid one. Superpower rivalry during the Cold War ramped up U.S. and Soviet space efforts to a scale that Western Europe had no motive to match.

The saddest fact of climate change - and the chief reason we should be concerned about finding a proper response - is that the countries it will hit hardest are already among the poorest and most long-suffering.

Tipping points are so dangerous because if you pass them, the climate is out of humanity's control: if an ice sheet disintegrates and starts to slide into the ocean there's nothing we can do about that.

We have known since the 1800s that carbon dioxide traps heat in the atmosphere. The right amount keeps the climate conducive to human life.

We need to send a message to Congress and the president that we want them to take the actions that are needed to preserve climate for young people and future generations and all life on the planet.