Disclosure: I read drafts of this book, and I’m in the acknowledgements. I’m also a donor to the Centre for Effective Altruism, which helped produce the book, and I’m about as close to a card-carrying effective altruist as you get, since I’m a member of Giving What We Can.

Let me cut to the chase: this is by far the best introduction to effective altruism that I’ve encountered. It’s not too long, it’s accessible, it’s remarkably comprehensive for it’s length, and it’s meticulously referenced (although not footnoted - the notes must be discovered at the back). If you have any interest in the subject, get it. To give you an idea how good it is, I’m writing this review without my copy because within a day of finishing it I’d lent it to an interested friend.

One of the things that has made effective altruism such a fertile movement is that the there is a core approach towards the problems, and many the ideas and activities that follow are just natural unfurlings of this approach.1 What MacAskill does in this book that’s so great is to lead the reader gently towards the core approach, at which point the rest is hard to resist.

The book’s sheer acessibility is a big part of what makes this work.2 The book treads the classic path of the populariser - start with an example or analogy to get the intuitive juices flowing, and carefully lead into the theory. Many of these examples are incredibly powerful. I think the hardest-hitting is the early analogy between charitably giving and medical triage, which puts a quite different perspective on charitable decisions. We have the world’s needless suffering lying at our feet, and the power to make a difference in our hands. And this quietly sneaks in two lessons from economics: opportunity cost, and prioritisation.

The hardest lesson is opporunity cost. Whatever we do, we do not do something else, and as a result of that, people may die. That’s a bitter pill to swallow, and it’s unsurprisingly a conclusion that people resist. This is why the analogy with triage is inspired - it harnessess powerful moral intuitions in the right direction. A key part of getting people on board with effective altruism is to get them to accept the reality of their own power in the world today (and hence the rather overwhelming opportunity cost that they will almost always face) without appearing to push the unattainable moral ideal of donating everything one owns. MacAskill does a good job of this, focussing on the positive opportunity that we have to do more good with our resources.

Triage also teaches us that, with our finite resources, we simply have to prioritise. That means that we will have to leave some people on the hospital floor. Taken seriously, this nixes the thought that effective altruists “don’t care” about people in first-world countries. It’s awful that we have to leave some work undone, but that can’t stop us from doing the most effective things first. Seen through the lens of triage, I think the moral case is very convincing.

While MacAskill uses powerful examples to support his moral arguments, many of the other examples are designed to subvert the reader’s intuitions. The first chapter is a devastating critique of the “PlayPump” - a charitable intervention that seemed wonderful, but ended up as anything but. As you read, it’s easy to think that this is going to be a success story. The impassioned founder, the innovative idea, the heavyweight backing: it all sounds good. Until MacAskill points out the fundamental problem: it doesn’t work. And you can’t tell that without testing it. The message throughout is clear: while your intuitions may be a guide to the right choice when you have all the facs, they can’t tell you those facts themselves, so there’s no substitute for doing your research and running the numbers.

The rest of the first half is devoted to motivating other aspects of the core approach: neglectedness, counterfactual reasoning, and reasoning under uncertainty. By and large, however, these are refinements to how we approach effectiveness, and I expect the reader will either have been sold on the core approach by this point, or not at all. That’s not to say that there aren’t tricky corners: embracing the possibility of low-probability high-impact interventions leads us towards existential risk mitigation, which can be a hard cause to love.

The second half of the book plays out the consequences. The insights here may seem obvious to those of us who’ve heard it all before, but they’re presented as forcefully as ever. The almost mis-placed emphasis on administrative overhead that used to dominate charity assessment is effectively skewered. We are encouraged to think critically about what the people we’re helping would actually want. The ethical aspect of career choice is re-evaluated. And finally the doors are thrown open to the speculative frontiers, where we might find opportunities that are even more drastically effective than our current best alternatives.

Throughout, MacAskill does a fine job of presenting the positive spirit of effective altruism. While it can seem at times like an abstruse, intellectualized movement, MacAskill reminds us that ultimately, the only reason we’re in this game is to improve people’s lives. We all want to do good, but effective altruism would really like to do good beter.

  1. If pressed, I would describe this as “economically informed empiricist consequentialism”. 

  2. Although I’m delighted to see that the two graphs that sold me on effective altrusim made it in: the graph of the global income distribution, and the graph of the varying effectiveness of medical interventions. For my money, the key insights are inherent in those two graphs.