The cannabis experience has greatly improved my appreciation for art, a subject which I had never much appreciated before.

The Platonists and their Christian successors held the peculiar notion that the Earth was tainted and somehow nasty, while the heavens were perfect and divine. The fundamental idea that the Earth is a planet, that we are citizens of the Universe, was rejected and forgotten.

It's sometimes easier to reject strong evidence than to admit that we've been wrong, this is information about ourselves worth having.

Who will speak for Planet Earth?

We are rare and precious because we are alive, because we can think as well as we can. We are privileged to influence and perhaps control our future. I believe we have an obligation to fight for life on Earth - not just for ourselves, but for all those, humans and others, who came before us, and to whom we are beholden, and for all those who, if we are wise enough, will come after.

But I try not to think with my gut. If I'm serious about understanding the world, thinking with anything besides my brain, as tempting as that might be, is likely to get me into trouble.

Every cell is a triumph of natural selection, and we’re made of trillions of cells. Within us, is a little universe.