The book is by William MacAskill, founder of 80000 Hours and Giving What We Can. Excerpt:
Effective altruism takes up the spirit of Singer’s argument but shields us from the full blast of its conclusion; moral indictment is transformed into an empowering investment opportunity...
Either effective altruism, like utilitarianism, demands that we do the most good possible, or it asks merely that we try to make things better. The first thought is genuinely radical, requiring us to overhaul our daily lives in ways unimaginable to most...The second thought – that we try to make things better – is shared by every plausible moral system and every decent person. If effective altruism is simply in the business of getting us to be more effective when we try to help others, then it’s hard to object to it. But in that case it’s also hard to see what it’s offering in the way of fresh moral insight, still less how it could be the last social movement we’ll ever need.
I'd like to play the devil's advocate here for a moment. I'm not entirely sure how I should respond to the following argument.
That begs the question: people often disagree on what is a better state of things. (And of course they say those who disagree with you are not "decent".)
Don't ignore the fact that people agree on only a very small set of altrustic acts. And even then, many people are neutral about them, or almost so, or they only support them if they ignore the lost opportunities of e.g. giving money to them and not to those other less fortunate people.
The great majority of things people want, they don't want in common. Do you want to improve technology and medicine, or prevent unfriendly AI, or convert people to Christianity, or allow abortion, or free slaves, or prevent use of birth control, or give women equal legal rights, or make atheism legal, or prevent the disrespect and destruction of holy places, or remove speech restrictions, or allow free market contracts? Name any change you think a great historical moral advance, and you'll find people who fought against it.
Most great causes have people fighting for and against. This is unsurprising: when everyone is on the same side, the problem tends to be resolved quickly. The only things everyone agrees are bad, but which keep existing for decades, are those people are apathetic about - not the greatest moral causes of the day.
Does selecting causes for the widest moral consensus mean selecting the most inoffensive ones? If not, why not? Do you believe that impersonal and accidental forces of history generate as much misery, which you can fight against, as the deliberate efforts of people who disagree with you? Wouldn't that be surprising if it were true?
I don't think that's the case. Karma based moral systems work quite well without it.
There a scene in "The way of the Peaceful Warrior" where the main person asks the wise man why the wise man doesn't do something substantial with his life but works in filling station. He replies that he's "at service" in the filling station. The act of being "of service" is more important than the value created with it. It's especially better than "trying" to do something from that perspective.