Combinations of Acts

Combining acts combines their risks. Their risks are not additive, either using their sizes or their intrinsic utilities. This creates the possibility of hedging, that is, adopting a risk to lower overall risk. Evaluation of combinations of acts that produce risks depends on whether the acts are simultaneous or in a sequence. Rationality evaluates a set of simultaneous acts as one act, given an ideal agent’s awareness of performing all together and at will. It evaluates a sequence of acts by evaluating its components one by one; their rationality suffices for the sequence’s rationality. This method of evaluation contrasts with evaluation of a sequence by comparing its utility to the utilities of rival sequences. Rationality does not evaluate sequences using utility maximization, even when the sequences bring neither unanticipated information nor changes in goals, because sequences are not options in the sense of being performable at will.