I'm interested in a system that allows a John Stuart Mill and an Anton LaVey to peacefully coexist without attempting to judge who is more 'objectively' moral. I wish to be able to choose my own terminal values without having to perfectly align them with every other agent. Morality and ethics are then the minimal framework of agreed rules that allows us all to pursue our own ends without all 'defecting' (the prisoner's dilemma is too simple to be a really representative model but is a useful analogy).

The extent and nature of that minimal framework is an open question and is what I'm interested in establishing.

I think rationality absolutely must confront the question of purpose, and head-on. How else are we to confront it? Shouldn't we try to pin down and either discard or accept some version of "purpose," as a sort of first instrumental rationality?

Why do you think it needs to be confronted? I know there are many things that I want (though some of them may be mutually exclusive when closely examined) and that there are many similarities between the things that I want and the things that other humans want. Sometimes we can cooperate and both benefit, in other cases our wants conflict. Most problems in the world seem to arise from conflicting goals, either internally or between different people. I'm primarily interested in rationality as a route to better meeting my own goals and to finding better resolutions to conflicts. I have no desire to change my goals except to the extent that they are mutually exclusive and there is a clear path to a more self consistent set of goals.

There's little to discuss if you don't, because "everything is permitted."

To the extent that we share a common evolutionary history our goals as humans overlap to a sufficient extent that cooperation is beneficial more often than not. Even where goals conflict, there is mutual benefit to agreeing rules for conflict resolution such that not everything is permitted. It is in our collective interest not to permit murder, not because murder is 'wrong' in some abstract sense but simply because most of us can usually agree that we prefer to live in a society where murder is forbidden, even at the cost of giving up the 'freedom' to murder at will. That equilibrium can break down and I'm interested in ways to robustly maintain the 'good' equilibrium rather than the 'bad' equilibrium that has existed at certain times and in certain places in history. I don't however feel the need to 'prove' that my underlying preference for preserving the lives of myself and my family and friends (and to a lesser extent humans in general) is a fundamental principle - I simply take it as a given.

First off, if westerners abandoned their western lifestyles, humanity would be sunk: next to the collapse of aggregate demand that would ensue, our present economic problems would look very mild.

Interesting. I'm not certain, but I think this isn't quite right. In theory, the westerners would just be sending their money to desperately poor people, so aggregate demand wouldn't necessarily decline, it would move around. Consumption really doesn't create wealth. Of course rational utilitarian westerners would recognize the transfer costs and also wouldn't completely neglect their own happiness.

All that said, I'd be really interested in reading a post by you on rationalist but non-utilitarian ethics. It seems to me that support for utilitarianism on this site is almost as strong as support for cryonics.

Unless you believe in objective morality, then a policy of utilitarianism, pure selfishness, or pure altruism all may be instrumentally rational, depending on your terminal values.

If you have no regard for yourself then pursue pure altruism. Leave yourself just enough that you can keep producing more wealth for others. Study Mother Teresa.

If you have no regard for others, then a policy of selfishness is for you. Carefully plan to maximize your total future well-being. Leave just enough for others that you aren't outed as a sociopath. Study Anton LaVey.

If you have equal regard for the happiness of yourself and others, pursue utilitarianism. Study Rawls or John Stuart Mill.

Most people aren't really any of the above. I, like most people, am somewhere between LaVey and Mill. Of course defending utilitarianism sounds better than justifying egoism, so we get more of that.

I don't think objectivity is an important feature of ethics. I'm not sure there's such a thing as a rationalist ethics. Being rational is about optimally achieving your goals. Choosing those goals is not something that rationality can help much with - the best it can do is try to identify where goals are not internally consistent.

I gave a rough exposition of what I see as a possible rationalist ethics in this comment but it's incomplete. If I ever develop a better explanation I might make a top level post.

I'd agree that signing up for cryonics and being a traditional utilitarian (valuing all human life equally) aren't really compatible. I'm not a utilitarian so that's not my problem with cryonics but it does seem to be hard to reconcile the two positions. It's hard to reconcile any western lifestyle with traditional utilitarianism though so if that's your main concern with cryonics perhaps you need to reconsider your ethics rather than worry about cryonics.

This may be a naïve question, but could someone make or link me to a good case for cryonics?

I know there's a fair probability that we could each be revived in the distant future if we sign up for cryonics, and that is worth the price of admission, but that always struck me as a mis-allocation of resources. Wouldn't it be better, for the time being, if we dispersed all the resources used on cryonics to worthwhile causes like Iodized salt, clean drinking water, or childhood immunization and instead gave up our organs for donation after death? Isn't the cryonics things one big fuzzy, or at least a luxury?

Why a 0.3 chance? Is that totally arbitrary? Also, it seems like a "boo" button would quickly become a means for people to indulge in inappropriate down-voting and feel insulated from responsibility for the outcome. It would also be a tempting false compromise between actually down-voting and doing nothing. Usually, one or the other is the right choice.

Those of you excited about this: aside from the presumed difficulty of implementing it, would it be even better if there were an option to actually vote -0.3 on a post, instead of voting -1 with 30% probability? And would it be even more of an improvement if you could choose to vote anywhere in the [-1, 1] range, so that you could mark something -0.7 or +0.25?

Those suggestions probably seem like an exaggeration, but I really do think we're all getting too worked up over the minutia of the karma system. This isn't a game. These numbers aren't our high scores. It feels like there's too much temptation to regard them that way, and further complexity to the system will only increase that.

An important, so-often-useful distinction. This reminds me of the Buddhist notion of fetters. Fetters are personal features that impair your attainment of enlightenment and bind you to suffering. You can cast them off, but in order to do so, you have to cut the crap and practice doing without them, with the full knowledge that it may takes many lifetimes to free yourself. It is not sufficient to announce your adhesion to the creed of enlightenment. The only things that make you do better are the things that make you do better. Everything else is window-dressing, or at best means to that end.

On another note...

I feel bad blogging about rationality, given that I'm so horribly, ludicrously bad at it. I'm also horribly, ludicrously bad at writing.

Is that hyperbolic self-effacement I detect?

I used to be worried about this, too. Then I found this beautifully concise term that resolves the whole question and ends semantic arguments over this arbitrary, imaginary distinction: agnostic atheist. This correctly describes me and I think it describes most other people who would call themselves agnostic or atheist. I encourage you to spread the term, and, when it's necessary or convenient, collapse the term into what you mean: atheist, which signifies only a lack of positive theism.

Also, Bertrand Russell explored this question thoroughly in his essay, "Am I an Atheist or an Agnostic?" I commend it as well for anyone who is confused about how to identify themselves.

On a side-quibble, I'm also careful about saying I'm "an atheist," with the article. I'm not "an" atheist in the same way a methodist is a methodist: my atheism doesn't mean I'm part of a discrete association of people. I don't go to atheist non-church with my fellow atheists on my unholy day. Think of how odd and even offensive it would seem, for instance, if we said each person with blue eyes was "a blue-eyed." Why? Socially, we would falsely be tagging him or her as merely a part of a greater faction of blue-eyed people. This is how nouns work in English: we have a set of social assumptions about "a doctor", but no such assumptions about "someone trained in medicine."

So "I am atheist" or, if you must, "I am agnostically atheist," work well.