Moral imagination, in order to realize its mental picture, must set to work in a definite sphere of percepts. Human action does not create percepts, but transforms already existing percepts and gives them a new form. In order to be able to transform a definite object of perception, or a sum of such objects, in accordance with a moral mental picture, one must have grasped the principle at work within the percept picture, that is, the way it has hitherto worked, to which one wants to give a new form or a new direction. Further, it is necessary to discover the procedure by which it is possible to change the given principle into a new one. This part of effective moral activity depends on knowledge of the particular world of phenomena with which one is concerned. We shall, therefore, look for it in some branch of learning in general. Moral action, then, presupposes, in addition to the faculty of having moral ideas (moral intuition) and moral imagination, the ability to transform the world of percepts without violating the natural laws by which these are connected. This ability is moral technique. It can be learnt in the same sense in which any kind of knowledge can be learnt. Generally speaking, men are better able to find concepts for the existing world than to evolve productively, out of their imagination, the not-yet-existing actions of the future. Hence it is perfectly possible for men without moral imagination to receive such mental pictures from others, and to embody them skillfully into the actual world. Conversely, it may happen that men with moral imagination lack technical skill, and must make use of other men for the realization of their mental pictures.
 In so far as knowledge of the objects within our sphere of action is necessary for acting morally, our action depends upon such knowledge. What we are concerned with here are laws of nature. We are dealing with natural science, not ethics.