The more a person's life is to be affected by some decision, and the more deeply affected, the greater his need to have learned good rational strategies that will help him to reach the best-supported of the options before him. If a student needs careful instruction in weighing up alternative words and phrases when translating from one language to another and in the devising of experiments to test hypotheses in science, he has still greater need for help in becoming able to cope rationally with the question of decision for or against an entire religious view, an ideology or a comprehensive speculative system. Young people are the constant targets of proselytising apologists for a very large range of conflicting views, for some of which a vastly stronger case can be made than for others. Yet though an alert critical vigilance and a capacity for clear-headed appraisal are so obviously important for discriminating among their claims, there exists a remarkable range of both religious and philosophical checks and impediments to developing and applying such appraisal.