[Modernman]

Another question then: what is the need for marriage?

I would say, historically, they served for one of two reasons:

1) To tie two families together and thereby increase the political or material assets of the families;

2) To establish a clear way for property to be passed down from generation to generation. Theoretically, all sons borne in wedlock were fathered by the husband.

Today, I think those two reasons don't really apply. Marriage serves as a form of social stability. Married couples are able to pool their various resources to improve their lives and the lives of their children.

[RightWhale]

Good points. There would be more than one way to administer such institutions. For example, in America a system of patriarchy was superimposed over an existing system of matriarchy when the Euros arrived. The matriarchy still exists although it is not recognized by the state.

[sr4402]

Another question then: what is the need for marriage?

Preserve mankind from evil and degeneracy.