How Bayesian Rationality Fails and Critical Rationality Works

The paper characterizes Bayesianism and critical rationalism as alternative recipes for judgment and decision making. It evaluates these alternatives against the background of the claim that following the respective recipe promotes the decision maker’s interests. Regarding Bayesian rationality, the claim is rejected, both for large and small worlds. Regarding critical rationality, the claim is accepted. It is argued that the critical-rationalist recipe works because it successfully exploits the laws governing human decision makers’ environment. The Bayesian recipe, however, is “too thin” to serve a decision maker’s interests.