Most of us have no problem operating under the notion that we should do unto others as we would have others do unto us. But what do we make of people who do go well beyond that, while asking for nothing in return? Why are often perplexed by those who are willing to put their health and well being on the line for complete strangers? Today’s guest is Larissa MacFarquhar, staff writer at The New Yorker and author of the new book Strangers Drowning: Grappling with Impossible Idealism, Drastic Choices, and the Overpowering Urge to Help.

MacFarquhar argues that we have a history of labeling people who help excessively as having some sort of physiological disconnect, a mental health condition that causes them to give more than what seems reasonable to the rest of society. She finds this resistance to do-gooders troubling, and that our defensive need to justify their behavior may say more about our own philosophical shortcomings than it does about the altruists among us.