Rationality still starts from experience
The idea that handling problems rationally means making a totally fresh start had been a mistake all along. All we can be called upon to do is to take a start from where we are, at the time we are there: i.e., to make discriminating and critical use of the ideas available to us in our current local situation, and the evidence of our experience, as this is ‘read’ in terms of those ideas. There is no way of cutting ourselves free of our conceptual inheritance: all we are required to do is use our experience critically and discriminatingly, refining and improving our inherited ideas, and determining more exactly the limits to their scope.
Stephen Toulmin, Cosmopolis