RE: Arguments against objective morality
I fail to see in history examples of terrible means achieving good ends. I know people (usually bad people) claim that the solution for a real problem is taxation, war or genocide, but when they implement their atrocities the result is just as bad as the means.
I can understand that it is possible that undesired means can lead to desired results, as when cutting someone's throat is the way to save his life making him breath again. I'm just saying that history (specially political history) is not full of examples like this.
I'd like to remember that the Non Aggression Principle (NAP) does not need to be the bedrock over which the whole morality rests in other to be useful. I see the NAP as a way of concentrating a huge philosophy of liberty and peace in a simple and easy sentence. Sure, it is not the ultimate perfect solution, but it is a very strong tool for us to use to understand the world. For instance, strikes can be classified as peaceful when the strikers do not attack those who show up to work, and not peaceful when they do. Nowadays people are used to think about strikes as a workers right, including aggression, but NAP helps us see that the violence used may render the whole movement immoral.
It's hard to come up with historical examples of something very bad that resulted in something very good. It might even be an impossibility, but let me propose a different look. Instead of expecting something good to be a consequence of something bad, let's look for something bad that could have gone much worse. That is easier find.
Some people genuinely argue that the Hiroshima bomb, while a tragedy, prevented the loss of innumerable more lives (something I don't quite believe myself). The killing of Bin Laden is another bad event (pre-emptive killing of people) considered a good act, because he was a dangerous man who could cause the death of tens of thousands of people. The extermination of animals carrying disease, the use of force to prevent crime, the destruction of private property (in sabotage operations) to disrupt oppressive regimes, the payment of taxes or the act of voting in order to ensure one's own safety or his family's. Don't you think this qualify as "good" coming from evil?
But I think this is a serious question: is it moral to do something immoral in principle, but that's believed to bring a better outcome? If you say no, then you're guilty of acting according to what feels good instead of what does good (you gutless phony). If you say yes, then your position is terribly close to a suicide bomber's who thinks the terrible loss of lives is a small price for obeying the will of his god. Imho, simply prioritizing principles or consequences over the other will lead to failed morality.