The second lecture Peter Achinstein gave in November, 2014 is now available on our YouTube channel, and below: 

Abstract: Isaac Newton famously claimed that hypotheses, i.e., unproved propositions, have no place in “experimental philosophy.” Maxwell disagreed and proposed three methods that can legitmately be employed when a scientist lacks proof for a theory, or even a theory to be proved. What are these methods, and are they legitimate?