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Reasons and Persons

Reviewing philosophy is as tricky as reviewing religious or meditation books — it matters more about where you are and what you need, than whether the book is "objectively" good or not. But since I run this place, I'll review from the perspective of how meaningful Reasons and Persons was for me. This was my second reading of a book that many regard as dense and difficult to get through. And it is. However, after reading Parfit, his biography, I wanted to go through the source material again.

There's this pattern that's happened several times in recent years: I adopt some life perspective or toolkit usually from interactions with others. And then I eventually read the source material—many are books reviewed here—which by then feels warmly familiar, and also mind blowing. Reasons and Persons was this for me: the source of many ideas that have become dear to me over the past few years.

This is the sort of book that feels like the output of a special, independent thinker that has a unique view of the world, and dances around ideas without a single cohesive terminus. Like Hofstaedter, Parfit offers an assortment of perspectives using many detailed examples. But where Hofstaedter's examples often have narriative structure, Parfit's feels more like formal logic. So, it is dense.

However, Parfit contributed more towards moral philosophy—especially how it is impacts culture today—than anyone else in recent memory. A friend refers to Parfit's contributions as baffling: nearly no one had meaningfully moved moral philosophy forward in a long time, and then Parfit offers several ideas that had basically been missed until him.

He explores moral theories, personal identity, and the implications of ethical decisions on future generations. "Common-sense morality"—the type of morality that most people have—is overall self-defeating. As in, if everyone adopted it, we'd be worse off. He explores precisely why this is the case, and uses this as a foundation to explore how self-interest impacts how we treat ourselves over time. What is your moral obligation towards your future self?

In fact, what makes a person the same person over time? This may feel like a strange or insignificant question, but ends up leading to powerful conclusions about ethics and morals. Furthermore, to what extent do people who don't (yet) exist have moral weight? Using examples about the effects of climate change and the potential trade-offs between quality and quantity of lives, he exposes the repugnant conclusion: "For any perfectly equal population with very high positive welfare, there is a population with very low positive welfare which is better, other things being equal." Which feels wrong: we don't morally optimize for population growth at all costs.

Reasons and Persons is for you if you want to explore the foundations of movements such as Effective Altruism, or care deeply about ethics and moral philosophy. It doesn't offer specific "here's how to live your life" advice, but has contributed significantly towards my own personal moral foundation. For that, I recommend, if this doesn't scare you away:

The book is long, and sometimes complicated. I have therefore separated my arguments into 154 parts…


These are entirely subjective, and roughly try to capture my personal enjoyment and usefulness, and how likely I'd recommend it to others. Don't read too much into this unless you love my judgement. Rough guidelines:

A: Top quartile. Changed the way I think about something.

B: Worthwhile. I took away something useful.

C: Didn't hit, wouldn't directly recommend. Likely won't revisit.

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