The two basic forms of action distinguished in the preceding articles, viz., moral action, where praxis is for praxis sake, and action for a good, where praxis is for the sake of theôria, are found in close relationship to one another in human life. The part they play is rather that of abstract moments in a practical process than that of self-contained and isolable bits of conduct. No philosopher is likely to discount the importance of thus analysing the concrete into its factors before he rectifies the abstraction by showing how they co-operate in actual experience. In any individual biography we can find acts and courses of action in which duty is the dominant motive, and others in which the dominant motive is desire of good. Similarly, when we compare different biographies with one another, some exemplify most strikingly the struggle for righteousness against unruly passion, others the spontaneous aspiration of the soul to attain the goal of its desire. But neither the moral law nor the summum bonum wields an exclusive sovereignty. St. Paul and Luther, in their warfare against carnal desire, drew strength from the ideal vision; nor were St. Bernard or Spinoza, for all their absorption upon union with the divine, strangers to the call of moral obligation. In the lives of ordinary men, the types of conduct are, perhaps, more evenly balanced; yet here also the distinction is discernible. Moreover, it is easy to see how, despite their intrinsic difference, they come to be associated and “by just exchange” to effect a mutual enrichment.