Double your Resources. You thereby double your life. One must not depend on one thing or trust to only one resource, however pre-eminent. Everything should be kept double, especially the causes of success, of favour, or of esteem. The moon’s mutability transcends everything and gives a limit to all existence, especially of things dependent on human will, the most brittle of all things. To guard against this inconstancy should be the sage’s care, and for this the chief rule of life is to keep a double store of good and useful qualities. Thus as Nature gives us in duplicate the most important of our limbs and those most exposed to risk, so Art should deal with the qualities on which we depend for success.