After dealing with the general rules of prudence, Crusius turns to its first area of application, that is, private affairs. He begins by noting that large parts of this study can be discarded, because they belong already to other sciences. Firstly, prudential care of one’s body and health belongs to medicine, secondly, prudential care of one’s understanding and intellect is the matter of logic, and finally, prudential care of one’s will and motivations has already been dealt in various parts of ethics and moral philosophy.
What is left for Crusius to consider is the prudential care of relationships with other people - in other words, how to get others to respect, honour and care for us. Unlike in case of proper moral philosophy, this is not so much a question of what one is deep down like and what an ideal, omniscient, God-like observer would say about one’s character, but more about how one appears to other people. Thus, although a person would be far from perfection in some field, she might still be respected, because she was viewed as perfect, at least when compared to other people.
Even so, Crusius is quick to warn his readers to avoid such a mere relative honour, because an honour based on being better than someone else will just create envy in others. In fact, he notes, lasting respect and honour must be based on true perfections. Furthermore, he continues, one should be careful in not bragging about one’s perfections and showing them only with good understanding, if one wants others to respect them.
A further, but related question Crusius considers is how to get people to love oneself. Love, Crusius defines, is awakened by perceiving perfections in someone and makes the lover attempt connecting with the beloved. Most often love is awakened, Crusius says, by perception of a perfection of will, because good will and good behaviour are signs of a person who is easy to connect with. Indeed, Crusius notes, a simple way to find love is to show love. Similarly, one should avoid things like mocking others and being ungrateful, if one does not want to be despised by others.
Crusius defines friendship as a type of love, more particularly, as connection of persons, in which both attempt to promote one another’s private ends. Because friendship is kind of love, Crusius advises, finding friends is a lot like making people love oneself. Indeed, he notes that best means for getting friends is to make oneself indispensable to others.
With this rather Dale Carnegian part of Crusius’ philosophy behind us, we have only one more part of the book to consider - that of prudential affairs of state.
