I didn't leave physics because of boredom. I left it because other issues compelled me in a bigger way. And I always say to myself, "When I'm 60, I'd like to go back to what I interrupted."

Population control is not an issue involving contraceptives for third world women. It is an issue of ecological justice.

I think we have reached a stage now where we need to find solutions to economic injustice in the same place and in the same ways that we find solutions to sustainability. Sustainability on environmental grounds and justice in terms of everyone having a place in the production and consumption system - these are two aspects of the same issue. They have been artificially separated and have to be put back again in the Western way of thinking.

We have a very old conservation movement, particularly in the United States, which has focused on campaigns to protect endangered species: the spotted owl, the old-growth forest. But usually it stops there. To me, biodiversity is the full spectrum. Species conservation is not only about wilderness conservation. It’s also about protecting the livelihood of people even while changing the dominant relationship that humans have had with other species. In India, it’s an economic issue, not just an ecological one.