ABSTRACT
Reasoning and decision making are topics of central importance in the study of human intelligence. Reasoning is the process by which we can apply our vast stores of knowledge to the problem at hand, deducing specific consequences from our general beliefs. Reasoning also takes place when we infer the general from the specific, by formulating and then testing new ideas and hypotheses. Rules for correct reasoning have been laid down by great thinkers in normative systems (principally logic and probability theory) and it is tempting to define, and evaluate, human rationality by referring only to these rules. However, we shall argue in this book that this approach is mistaken. The starting point for any understanding of human rationality should be behavioural: we must ask how decisions taken and actions performed serve the goals of the individual. Formulating and making use of logical and other rules has always had to rest on a more fundamental human ability to achieve behavioural goals.
