ABSTRACT
Are people “rational” or not when they test their ideas against reality? Are they enlightened falsifiers or conservative confirmers? And what is rational? These are the basic issues at stake in most research on human hypothesis testing and, likewise, also gave the impulse to the present study. Throughout this essay, these questions have been treated at different levels. First, the theoretical level. I derived the striking equivalence between a confirming and a falsifying strategy, because whoever falsifies confirms, and whoever confirms, necessarily falsifies. It was demonstrated in the philosophical section that the two standards of testing, although emanating from the rival philosophies of logical positivism and falsificationism, surprisingly prescribe exactly the same testing behaviour.
