Ben Levinstein: Evidential Decision Theory and the Ostrich

Ben Levinstein (University of Illinois, Urbana-Champaign)
Evidential Decision Theory and the Ostrich (coauthored with Yoaav Isaacs)

Evidential Decision Theory is flawed, but its flaws are not fully understood. David Lewis famously charged that EDT recommends an irrational policy of managing the news and “commends the ostrich as rational.” Lewis was right, but the case he appealed to---Newcomb's Problem---does not demonstrate his conclusion. We offer a new case which shows that EDT mismanages the news, thus vindicating Lewis's original charge. We argue that this case reveals a flaw in the “Why ain'cha rich?” defense of EDT. We argue further that this case is an advance on extant putative counterexamples to EDT.