In the 1950s, Davidson worked with Patrick Suppes on developing an experimental approach to Decision Theory. They concluded that it was not possible to isolate a subject's beliefs and preferences independently of one another so there would always be multiple ways to analyze a person's actions in terms of what they wanted or were trying to do or valued. That result was comparable to Quine's thesis on the indeterminacy of translation and figured significantly in much of Davidson's later work on philosophy of mind.