Introduction to Althusius' Politica

"Politics is the art of associating (consociandi) men for the purpose of establishing, cultivating, and conserving social life among them. Whence it is called "symbiotics." The subject matter of politics is therefore association (consociatio), in which the symbiotes pledge themselves each to the other, by explicit or tacit agreement, to mutual communication of whatever is useful and necessary for the harmonious exercise of social life."

Thus Althusius begins his Politica (p.17). His vocabulary does present some problems to the casual reader so I would like to help clear things up a bit. First, we should not read politics as referring to the squabbles of political parties. Nor does he have in mind political government per se. He is seeking to explain the principles underlying every association between individuals (government, church, family, professional associations, &c.). Art is used in the sense of a subject of inquiry or a skill.
Symbiotics is from a Greek word meaning "living together." The symbiotes are, therefore, those who live together (or associated together for whatever purpose they are so associated). Communication is sharing, related more to communion (the modern word indicates the sharing of ideas, words, thoughts, &c.). This is how the older English versions of the Bible use the term (typically rendered fellowship in newer versions).
One should note that Althusius was committed to the "social contract" theory of politics before the Enlightenment formulation. However, Althusius' preferred word would be covenant. As man's relationship to God is covenantal, so is his relationship with the rest of mankind. And so his understanding of politics includes elements of piety: "The end of political "symbiotic" man is holy, just, comfortable, and happy symbiosis, a life lacking nothing either necessary or useful."
Althusius constructs his Politica on divine & natural law, both conceived as coming from the Lord. As such his politics assumes the liberty of mankind (though this was less a concern before Thomas Hobbes). Along with the mutual agreement of the members of the political body being considered is the belief that human sovereignty in a commonwealth lies not with the prince but with the people as a whole. He concludes "that the efficient cause of political association is consent and agreement among the communicating citizens." (Page 24). Of course, these ideas are at the very heart of our free society (or at least they were).