 Causal decision theory may also explain that it advances a claim about the evaluation of an act given the agent’s circumstances in Newcomb’s problem. It asserts two-boxing’s conditional rationality. Conditional and nonconditional rationality treat mistakes differently. In contrast with conditional rationality, nonconditional rationality does not grant past mistakes. It evaluates an act taking account of the influence of past mistakes. However, conditional rationality accepts present circumstances as they are and does not discredit an act because it stems from past mistakes. Causal decision theory maintains that two-boxing is rational, granting the agent’s circumstances and so ignoring any mistakes leading to those circumstances, such as irrational preparation for Newcomb’s problem.