I’d say they also have to have a mutual understanding of the voluntary words and actions and I think that leads back to the social contract.
Shalom Israel wrote: “There's no way I can bind you by an "implicit contract" against your will. It's in no way analogous to a "social contract", which binds me from birth through no action of mine.”
Disregarding the truth or falsity of your first sentence, neither I nor tpaine (if I recall correctly) have said a “social contract” binds you from birth through no action of yours. One way or another we have both said that you can opt out. I say that you can be an outlaw and in short tpaine says that you are free to “renounce citizenship and/or leave.”
I’m not a professional user of logic, but it seems to me that you offered an approximation of what we say, knock it down, and gave the appearance (at least superficially) of negating it.
I see most of your PS as containing arguments in favor of the concept of the social contract, but it does not please me to address that right now.
It does not, precisely because the mutual understanding does not carry with it any obligation. I can avoid any and all of the many implied contracts embodied in our culture. I don't have to let you ring my doorbell: I can put a sign up that says, "No visitors: violators will be shot." I can invite you to lunch by saying, "Yo, Kris, come on over for lunch--but if you tick me off, I promise I'll shoot you. Matter of fact, sign this, in case the police want some proof..."
By contrast, your "social contract" imposes obligations I can't get out of. I can't notify the IRS that I'm not paying their protection money anymore. If a police officer bashes in my door, I can't shoot him in self defense.
I see most of your PS as containing arguments in favor of the concept of the social contract, but it does not please me to address that right now.
Your little flourish on the end is kinda cute. However, "implied contracts" differ critically from "social contracts": namely, I can always refuse to enter into an implied contract by so stipulating. A "social contract" imposes terms on me that I can't escape by any means, even though I didn't agree to it.
What makes the two appear superficially similar is that people go around making presumptions: for example, the obnoxious so-and-sos will go ringing my doorbell unless I take positive steps to prevent it. But that's not because I'm trapped in a social contract which forces me to tolerate doorbell-ringing; I can in fact put a stop to it in several different ways. Rather, just as I said, it's a matter of communication. Cultural norms tell Americans that they should assume they can ring my doorbell; in Gondwanaland, cultural norms tell people that they should stand back six camel-lengths and whistle Dixie instead.
The resolution of the conundrum is to realize that these cultural norms are part of the language. They don't obligate me. It's simply that many types of agreements are so standard, that people can enter into them with few or no words. Simply crooking my finger constitutes an invitation to come closer, and a promise that when you get real, real close, I won't punch you in the eye.
But language does carry a cost: when it allows you to compress certain messages into a word, a wink or a nod, it leaves you no choice but to speak a lengthy sentence in order to communicate a different message.
Thus, in American, I can invite people to come seek my attention merely by having a doorbell and taking no other action. If I want to tell them to buzz off, which is an unusual message in American, I must use more extensive means of communication.
Deep in the backwoods of Yakutsk the situation is exactly reversed: a Yakut seeking someone's attention must stand outside the person's property and yodel. IF the property owner wants you to stand back and yodel, he need take no special action. If he wants you to march right up to his yurt and say howdy, he needs to take more complicated measures to communicate that to you.