We assume therefore that moral virtue is the quality of acting in the best way in relation to pleasures and pains, and that vice is the opposite.
Every realm of nature is marvelous.
It is the active exercise of our faculties in conformity with virtue that causes happiness, and the opposite activities its opposite.
Demonstration is also something necessary, because a demonstration cannot go otherwise than it does, ... And the cause of this lies with the primary premises/principles.
Not every action or emotion however admits of the observance of a due mean. Indeed the very names of some directly imply evil, for instance malice, shamelessness, envy, and, of actions, adultery, theft, murder. All these and similar actions and feelings are blamed as being bad in themselves; it is not the excess or deficiency of them that we blame. It is impossible therefore ever to go right in regard to them - one must always be wrong.
Whether we will philosophize or we won't philosophize, we must philosophize.
For this reason poetry is something more philosophical and more worthy of serious attention than history.
In inventing a model we may assume what we wish, but should avoid impossibilities.
