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

If we're going to make a politically responsible and a scientifically sensible claim it should not be stop the world exactly where it is because that's not possible. It has to be to decide what kind of world do we as human beings want to live in.

If I ask you who is the most famous scientist who ever lived, or the greatest scientist who ever lived you'll say either Einstein or Newton or something like that because their claims were supposed to apply universally. But the claim of somebody who is studying a particular feature of the evolutionary process like whether it's very fast or very slow, or occurs in steps and so on, that's not a universal claim, that's a rather specialised claim and so you can't claim to great fame and great success.

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.

I assume the same problem exists in Australia as in America of back-biting and jealousy and parochialism among disciplines - there are the scientists, and there are the humanities people, and there are chemists and the physicists and everybody snipes at everybody else and inter-disciplinary communication is rare. But it's very precious and necessary.

An ecosystem, you can always intervene and change something in it, but there's no way of knowing what all the downstream effects will be or how it might affect the environment. We have such a miserably poor understanding of how the organism develops from its DNA that I would be surprised if we don't get one rude shock after another.

The social scientist is in a difficult, if not impossible position. On the one hand there is the temptation to see all of society as one's autobiography writ large, surely not the path to general truth. On the other hand, there is the attempt to be general and objective by pretending that one knows nothing about the experience of being human, forcing the investigator to pretend that people usually know and tell the truth about important issues, when we all know from our own lives how impossible that is.