Every skill and every inquiry, and similarly every action and rational choice, is thought to aim at some good; and so the good has been aptly described as that at which everything aims. But it is clear that there is some difference between ends: some ends are activities, while others are products which are additional to the activities. In cases where there are ends additional to the actions, the products are by their nature better than the activities.

Since there are many actions, skills, and sciences, it happens that there are many ends as well: the end of medicine is health, that of shipbuilding, a ship, that of military science, victory, and that of domestic economy, wealth. But when any of these actions, skills, or sciences comes under some single faculty – as bridlemaking and other sciences concerned with equine equipment come under the science of horsemanship, and horsemanship itself and every action in warfare come under military science, and others similarly come under others – then in all these cases the end of the master science is more worthy of choice than the ends of the subordinate sciences, since these latter ends are pursued also for the sake of the former. And it makes no difference whether the ends of the actions are the activities themselves, or something else additional to them, as in the sciences just mentioned.