Evolutionary psychology is a field that uses evolutionary theory to explain why the human mind is the way it is. Some philosophers, such as Hume, thought the human mind starts as a blank slate with certain general capacities to learn. Natural selection says that humans come with more built in to their minds than we previously thought. How do these two views differ? To help with the discussion, Ken introduces Leda Cosmides, an evolutionary psychologist at UC Santa Barbara. Cosmides gives some background about the field of evolutionary psychology. Then, she gives an example to show how evolutionary psychology sheds light on human behavior, the problem of inbreeding. She explains what mechanisms developed in the mind to turn off romantic interest in siblings. 

Evolutionary psychology seems to allow us to predict moral attitudes about certain acts based on postulated mental mechanisms. These mechanisms seem to provide some knowledge that could not exist on, say, a Humean conception of the mind. Further, they account for both altruism and avoidance of incest. Ken resists by asking if culture doesn't allow for transmission of acquired information across generations. Don't cultures vary greatly? Isn't this a counterexample to evolutionary psychology? Cosmides denies that claiming humans have a capacity for culture really solves anything. What algorithms could be brought in to explain cultural issues? Are culture and evolution separate streams for information transfer?

How does evolutionary psychology make sense of adaptations that were beneficial for our ancient ancestors but that are bad for us now. Ken thinks this raises a philosophical problem about "ought" and "is". He points out that we need to be careful about inferring from what evolutionary psychology says WAS the case, how our ancestors did behave, to what ought to be the case, how we should behave today. John asks whether the cognitive architecture required by Darwinian algorithms could accidentally result in brains that are capable of handling more complicated things, like quantum physics. Ken follows up by asking how evolutionary psychologists differentiate between activities we do now, such as philosophy and physics, and activities that were adapted for in our ancestors, such as kin identification. Cosmides gives some examples of ways in which evolutionary psychologists differentiate between these two kinds of tasks.

• Roving Philosophical Report (Seek to 05:36): Amy Standen interviews a psychology professor about the sex specific differences in males and females. The professor talks about how our basic behavior is the same as that of our ancient ancestors.

• Sixty-Second Philosopher (Seek to 49:54): Ian Shoales gives a short history of standardized intelligence tests.