ENGLISH COMMENTARY
instance, principles of intellectual inquiry, like Descartes's rules for gaining clearness and distinctness in science. In ch. 13 Marcus calls this method 'physiology'.
Although the suggested inquiry applies to all objects presented to the mind of an observer, the interest of the moralist is in good, evil, and indifferent imaginations, right and wrong thoughts. Marcus is especially alive to what we call ideo-motor activity, the effect of imagination upon impulse, the tendency of impulse to realize itself in action. This is what in ch. 13 he calls 'pathology'.
The third stage of moral science is called 'dialectic' in ch. 13. This word stands for the inward debate upon the objects which have been systematically examined in the stages of 'physiology' and 'pathology', what we may call the logic of moral science. This kind of inquiry is into what he calls here 'its function in the world and the length of its duration'.
An illustration from the Manual of Epictetus and the commentary of Simplicius may make Marcus' meaning precise and clear.
'Make it your study', says Epictetus, 'to face every difficult imagination of your mind at once with the words: "You are an imagination and not entirely what you appear to be." Next test it by your canons of thought, and first and above all by this: "Does it or does it not concern what is within the power of the will or not?" If it be concerned with what is not in the power of the will, be ready with the maxim: "This is no concern of mine."'[1] Simplicius' comment is: 'First say: "You are a mere imagination." To say this checks its power, because you realize that it may present or represent what is true, your benefit or even your pleasure; again it may be only a dreamlike fantasy. Having thus checked its immediate tendency to set up an impulse in you to give it effect in action, ask whether it refers to a spiritual good, a good of the flesh, a mere external good. Next ask whether its reference is to benefit or merely to pleasure; then whether it is practicable or impracticable. Then ask what the wise or the foolish would say to it, what God would have to say about it, and generally whether, if practicable, it is practicable for yourself or not.'[2]
