People must therefore (1) have a head. If they have no head, association becomes impossible; and if two coequal heads jointly preside over a group, the association breaks down.
This is firmly rooted (2) in the natural dispositions of all people. If there are two rulers, they must take turns (3) exercising authority, so that one obeys the other (4) on one occasion and the other obeys the first (5) on another. This is seen among the aides and ministers of kings: when one initiates a course of action (6), the other assists him in it. If (7) they do not agree, the matter is referred to someone above them. Otherwise, one and the same course of action cannot originate from two people jointly unless both are subordinate in it to a third.
Mutual obstruction thus occurs between two coequal principals, whether they are assumed (8) to agree or disagree. It is more evident when they disagree; yet they likewise obstruct one another (9) even when they agree. One of them cannot (10) act until the other acts (10 and the latter cannot act until the former acts 10) (11), and they have no third party to move them to act. Neither has any greater claim than the other to act first. Moreover, for the act to proceed from them both, when (12) the act of each necessarily requires the power to perform it (13), while each has no such power except through