From The Conversation’s inception, geoengineering—the deliberate manipulation of the climate through technology—has been high on my list of subjects to include in the series. To address the issue, I spoke with David Keith, a Harvard professor with a joint appointment in Applied Physics and Public Policy. David has spent the better part of two decades researching climate science and geoengineering, was named a Hero of the Environment by TIME in 2009, and is also the President of Carbon Engineering, a startup dedicated to reducing atmospheric CO2. He is also publicly visible, having testified before the US Congress, spoken at TED, and appeared on numerous television and radio programs in an effort to spark a broader conversation about geoengineering. During these appearances, David steps refreshingly beyond science and into the thorny moral and philosophical questions raised by geoengineering—and that is exactly why I invited him to join The Conversation.

David’s conversation starts with a tiny parcel of information about geoengineering but, within minutes, we’re into questions of value. If you’ve been listening to The Conversation for a while this will feel like we skipped over the usual foundation of information I try to build at the beginning of each episode, so you may actually want to skim the Wikipedia link up top.

That out of the way, we return to the anthropocentrism/biocentrism theme that characterized many earlier episodes from John Zerzan to Robert Zubrin. Echoing Carolyn Raffensperger, utilitarian philosophy finds itself in the line of fire again as David argues that utilitarianism is insufficient to justify meaningful environmental preservation. At one point, Wes Jackson (explicitly) and Douglas Rushkoff (implicitly) come up in conversation as we discuss what is knowable and, conflating Jackson and Zerzan, David smacks down Zerzan’s neoprimitivism. This list could stretch for pages, but let’s conclude here with a connection between David and John Fife, both of whom see the obsolescence of the nation state, though for very different reasons.

Artwork by Eleanor Davis.