Problems for the causal theory of knowledge led epistemologists to propose that knowledge is a matter of tracking the truth. Fred Dretske and Robert Nozick developed this idea using counterfactual conditions. In this Wireless Philosophy video, Geoff Pynn (Northern Illinois University) examines the tracking idea, consider how it improves on the causal theory, and then discuss some well known objections to the theories advanced by Dretske and Nozick.