The more important question for Aristotle is why one needs to be on the giving end of this relationship. The only underived reason for action is self-interest; that an act helps another does not by itself provide a reason for performing it, unless some connection can be made between the good of that other and one's own.
The strong form of egoism we have been discussing cannot accept Aristotle's doctrine of the priority of the city to the individual. Aristotle defines moral virtue as a disposition to behave in the right manner and as a mean between extremes of deficiency and excess, which are vices.
Second, actions performed out of ignorance are also involuntary. Consider someone who loves to wrestle, for example. Aristotle indicates several times in VII. The sign of what is natural, for Aristotle, is pleasure, but we have to know how to read the signs.
Modern science develops theories about the physical world based on experiments and careful observation—in particular, on the basis of exact measurements of time and distance. His desires for pleasure, power or some other external goal have become so strong that they make him care too little or not at all about acting ethically.
His reply, of course, is that nature has given us work to do, in default of which we are necessarily unhappy, and that work is to put into action the power of reason. The grandest expression of ethical virtue requires great political power, because it is the political leader who is in a position to do the greatest amount of good for the community.
But the account of friendship points to the healthy community, in which civil war and other conflicts are driven away by the choice of what is beautiful in life. Book VII offers a brief account of what pleasure is and is not.