DEUT60 While for analytical purposes ethics is content with the study of the springs of human behavior and their expression, for practical ends of directing the lives of men, it is more exacting. Not what is being done, but what ought to be done constitutes its measure of value. Whereas science speaks in the indicative mood, religion uses the imperative. Its characteristic expressions take the form of commands and prohibitions, thou shalts and thou shalt nots. ("'This is your wisdom and your understanding,' says [this verse], with reference to the law. When Kant calls the force that decrees, teachers, makes demands, by the term 'practical reason,' he but uses another expression for morality. Call it law, principle, idea, what you will, it is always an objective norm, in nowise depending upon the pleasure of man, but constraining him as he knows himself to be constrained by the laws of logic when he thinks, by the laws of mathematics when he competes." Lazarus, The Ethics of Judaism, p. 117.)