Ethics are very weird.
Most ethical systems are reward-based. We do the right thing because we get rewarded. Society rewards us by not throwing us in jail, for example. We get a biscuit for good behavior. We get a place in Heaven.
But not all ethics are based on rewards. Some, especially the one's that challenge the existence of a big man upstairs, are based on happiness. Whatever makes you happiest. Well, that's not too great a system, I mean, if puppy-murderin' makes me happiest then perhaps others might by sad by my actions. So happiness needs to take account of others. And that's true of all of them. Except Buddhism, which is entirely inward-looking. Selfish Buddhists.
But let's take a look at the old Utilitarian argument again. John Stuart Mill came up with the best version: The best thing in life is happiness. Happiness is better for more people than one, so we should try and maximize happiness for the most amount of people. Happiness is the goal in life because it is the privation of pain, and since all people feel pain equally, or similarly, he assumes that all people are equally capable of feeling happy.
It's an ethic of equality, which is why I like it. Everyone can feel the same pain as you, everyone can feel the same pleasure. Now some pleasures, Mill is quick to point out, are better than others. Sensual pleasures take a back-seat to intellectual pleasures, for example. I don't know if that's true, but it's tangential anyway, so I won't bother with it.
Peter Singer is a modern Utilitarian. They're hard to come by these days. One of the main reasons is a logical fallacy in Mill's work. On page one, ironically, he makes a logical conclusion that the rules of logic won't allow. So many people were able to dismiss Mill for that error, since that's what philosophy is about.
I don't care. I don't care a fig anymore about that fallacy, I did, but I got over it. The idea that more happiness for more people is not logically sound doesn't matter to me, it's still a good idea. Singer makes the point that those who have the means, if convinced by Mill's standpoint, should help starving children. Here and in Bangladesh. It doesn't matter where, because children everywhere can feel pain the same way.
He takes it a step further and points out that animals, too, have the same sort of nervous system as us. That's what it comes down to, after all. The ability to feel pain, and pleasure. And since animals can he advocates not killing them, or torturing them. I suppose some are okay to torture by that logic, like clams, since clams don't have a central nervous system. I'll have to ask him about it.
So I sponsor children when I can. When I can commit money to a program that gives money to children I do. I've also become a vegetarian. Not for the reason Mill provides, but I do find them to be valid, and an extra source of support. You need not do either of these things, but you may consider them if you're swayed by the idea that the more happiness on this planet the better. Or even if you aren't.