Precautionary Reasoning and Decision Theory

Decision theory is the study of how people make rational choices, where rationality is defined as taking effective means to one’s goals and conforming to the rules of logic and axioms of probability theory (Resnik in Choices: An Introduction to Decision Theory. University of Minnesota Press, Minneapolis, MN, 1987; Peterson Introduction to Decision Theory, 2nd ed. Cambridge University Press, Cambridge, UK, 2017). As noted in Chap. 1, this type of rationality, known as instrumental rationality, is different from reasonableness because reasonableness is founded on moral and social values. A decision could be rational in the decision theorist’s sense but not reasonable. For example, it might be rational to jump off a tall building to commit suicide (if that is one’s goal) but not reasonable to do this.