What I'm really hoping to see are heuristics that take less than a second to think through; but if you want a well-defined line, how about I draw on a completely inapplicable cliche, and define it as a five-second rule - if it takes more than five seconds to think through, it's almost certainly too complicated for what I'm hunting for.
For example - at a bar, a bar fight breaks out next to you. The Pacifism rule-of-thumb is simple - don't start fighting, or even fighting back. ZAP doesn't take much more effort; don't start fighting, unless someone attacks you. (ZAP with 'common defense' is almost as easy - don't start fighting, unless someone attacks you or the people you've previously decided you're willing to fight to defend.) Proportional response is slightly more complicated still, but still doesn't take much thought - if nobody attacks you (or the people you'll fight for), don't get involved; if it's a relatively harmless fistfight brawl, don't pull a gun and start shooting; etc. At any given point, the limits on your actions that any of these ethical rules-of-thumb place are clear enough that you almost don't have to do any thinking at all to figure out.
'Check consequentialism' seems to be a guideline of a somewhat different nature. In the sort of nearby bar-brawl described above, it's hard to tell ahead of time what this heuristic would lead you to conclude - or to tell how long it would take you to figure out what to do - or make any predictions at all, really. It doesn't seem to place any specific limits on your actions, limits which may reduce your short-term benefits but also provide long-term gains (eg, "For the good of the tribe, don't murder").
It's entirely possible that I'm mixing up aspects that my baseline rules-of-thumb have in common with what's actually most useful about them; but since I seem to have gotten as far as I can in my reasoning on my own, it seems worthwhile to try to evoke some assistance from anyone I can here.
Rules-of-thumb are handy, in that they let you use a solution you've figured out beforehand without having to take the time and effort to re-derive it in the heat of the moment. They may not apply in all situations, they may not provide the absolutely maximally best answer, but in situations where you have limited time to come up with an answer, they can certainly provide the best answer that it's possible for you to come up with in the time you have to think about it.
I'm currently seeking fairly fundamental rules-of-thumb, which can serve as overall ethical guidelines, or even as the axioms for a full ethical system; and preferably ones that can pass at least the basic sniff-test of actually being usable in everyday life; so that I can compare them with each other, and try to figure out ahead of time whether any of them would work better than the others, either in specific sorts of situations or in general.
Here are a few examples of what I'm thinking of:
* Pacifism. Violence is bad, so never use violence. In game theory, this would be the 'always cooperate' strategy of the Iterated Prisoner's Dilemma, and is the simplest strategy that satisfies the criteria of being 'nice'.
* Zero-Aggression Principle. Do not /initiate/ violence, but if violence is used against you, act violently in self-defense. The foundation of many variations of libertarianism. In the IPD, this satisfies both the criteria of being 'nice' and being 'retaliating'.
* Proportional Force. Aim for the least amount of violence to be done: "Avoid rather than check, check rather than harm...". This meets being 'nice', 'retaliating', and in a certain sense, 'forgiving', for the IPD.
I'm hoping to learn of rules-of-thumb which are at least as useful as the ZAP; I know and respect certain people who base their own ethics on the ZAP, but reject the idea of proportional force, and am hoping to learn of additional alternatives so I can have a better idea of the range of available options.
Any suggestions?