Free Choices: Essays on Rational Decision-Making and the Authority of the Laws of Nature

Abstract

There is an intuitive tension between making a decision and believing the outcome of that decision might be predetermined - what would be the point of deciding what to do if there is only one thing you can do? In this thesis I offer way to understand this tension formally and precisely in the language of our best theory of rational decision-making: Causal Decision Theory (CDT). If there are epistemically possible states of the world which are causally independent of an option but inconsistent with it, then CDT's expected utilities are undefined: such option-state pairs must be assigned non-zero probability, but they have undefined utility. Since the past and the laws of nature are outside our causal control, the possibility that together they predetermine the outcome of a choice supplies examples of such states. This is Causal Decision Theory's Predetermination Problem. And, as I will show, the problem also arises from the possibility that the laws of nature constrain, without predetermining, a choice and that the laws of nature entail that a choice is a matter of chance. CDT has a problem with the (possible) authority of the laws of nature over our choices, whatever form that authority takes. This is Causal Decision Theory's Problem with Authority. There are three categories of solution to the problem: First, deny that it is possible, in the sense relevant to decision-making, that our choices fall under the authority of the laws of nature. Second, deny that the past and the laws of nature are outside our control, in the sense relevant to decision-making. Third, offer an account of how good it would be if an inconsistent option-state pair obtains. Each category has a distinctive cost: The first forces us to bet against our evidence. The second forces us to give up CDT's raison d'etre - taking both boxes in Newcomb's Problem. The third forces us to endorse options which we are rationally certain will do worse than any other. None of these options is attractive. I will introduce a new decision theory in the first category - Libertarian Decision Theory (LDT). LDT is able to capture just the right sort of compatibilism about rational decision-making and the authority of the laws of nature, and we can defend betting against our evidence when our evidence shows we lack alternative options or effective control over them. The possibility the laws merely constrain our choices is more of a challenge for Libertarian Decision Theory. However, Libertarian Decision Theory improves on previous solutions to Causal Decision Theory's Problem with Authority. Show more