Like all biologists I simply acknowledge the gravity of the current situation. There are scenarios under which things work out well and to that extent I'm a cautious optimist.

History has got a lot to do with unique circumstances under certain particular cases and grand theories will always find counter cases. I don't think that people whose expertise lies in one thing should try to make grand theories about something (a) where it's very hard to get the evidence to prove that you're right and (b) where it's much too easy to make up stories that seem right.

I think people who worry about planetary health on geological scales are totally misguided, that's not the point at all.

If I put myself on the side of those who see the world as warming up in a bad way, who see the general march of industrial culture as something undesirable, the one thing I must be beware of doing and which my colleagues on that side don't beware of doing, we must beware of saying we've got to stop changing the environment. There is no 'the' environment which we can change, the world is changing all the time.

The vulgarization of Darwinism that sees the "struggle for existence" as nothing but the competition for some environmental resource in short supply ignores the large body of evidence about the actual complexity of the relationship between organisms and their resources.

In my mind the job of a natural scientist is to bend over backwards to say something which can be demonstrated to be true or at least which is not of such a nature that there's no way to demonstrate that it's false.

Scientists are educated from a very early time and a very early age to believe that the greater scientist is the scientist who makes discoveries or theories that apply to the greatest ambit of things in the world. And if you've only made a very good theory about snails, or a very good theory about some planets but not about the universe as a whole, or about all the history of humankind, then you have in some sense accepted a lower position in the hierarchy of the fame of science as it's taught to you as a young student.