Australian intellectuals Val Plumwood and Richard Sylvan pioneered environmental thinking.
Eminent twentieth-century philosophers, they were determined to fuse the practical and the intellectual, to 'walk the talk', when it came to the environment.
Dr Dominic Hyde, an Honorary Senior Lecturer in Philosophy at the University of Queensland and student of the pair, published a book about them in 2014.
We chatted about their work, as well as some of the basics of environmental philosophy, a surprisingly under-explored area considering how "big" the environment is in people's minds.
The conversation starts with Hyde's assessment on the current state of green activism in Australia.