A civil community, such as the state, is bound by a sort of friendship, but for the state to achieve its end, which is the good of its members, something more is needed than the mere bond of friendship. Civil authority is needed. Si ergo naturale est homini quod in societate multorum vivat, necesse est in hominibus esse per quod multitudo regatur. If therefore it is natural for man to live in a society of many, it is necessary that there be something among men by which the multitude is governed. Diversorum autem diversae sunt causae.
Diverse things have diverse causes.
From the above, we can see that civil authority would still be needed even if all the members of society were perfect and unselfish. Each person does well taking care of his own concerns, but if people are going to act together to accomplish greater things that benefit everyone, leadership and authority are needed. This is very much different from the theory of Thomas Hobbes, that men are by nature enemies one to another, and that they submit to authority as a way to end the war of all against all . Thomas sees that the normal attitude is that men help each other in need, while admitting that civil authority is also necessary to restrain those who do not act according to the norm and to defend the community against external enemies. However, a mere willingness to help others is not enough, if this natural inclination is going to be effective, than it must be guided by authority.