Thesis: Ph. D., Massachusetts Institute of Technology, Department of Linguistics and Philosophy, 2016.Cataloged from PDF version of thesis.Includes bibliographical references (pages 137-141).In this thesis, I sketch a decision-theoretic picture of instrumental rationality, which I call the Actual Value Conception: roughly, that you should align your preferences over your options to your best estimates of how the actual values of those options compare. Less roughly: for any options, q and 0, you are instrumentally rational if and only if you prefer q to / when, and only when, your best estimate of the extent to which O's actual value exceeds 's is greater than your best estimate of the extent to which O's actual value exceeds O's, where an o...