Introduction

The progress of the ‘behavioural Sciences’ is inexorable and accelerated. You are unlikely to keep up. Should you threaten to catch up, we will define what we gave you as passé and give you something new. Should we run out of new stuff, which is not very likely, we will change the nature of something we have already promoted to you as ‘the answer’, and which we have displaced with some ‘new answer’ and then give it to you again.