Objections to longtermism often focus on issues like fanaticism, discounting, or classic reasons to doubt the tractability of positively influencing the far future. I argue that another challenge has been underdiscussed relative to those—namely, that posed by unawareness: many of the long-term possibilities most relevant to our actions are unknown to us. I develop this challenge by introducing the notion of determinative unawareness, where unknown outcomes are decisive for whether an action is overall positive or negative. Greaves and MacAskill's responses—treating unawareness as ordinary uncertainty or appealing to catchall states—do not, by themselves, suffice, as it is far from clear how they can avoid arbitrariness. Importantly, I argue that existing cases outlining the relative robustness of some longtermist strategies, such as option value maximization, do not ultimately succeed in sidestepping determinative unawareness. I then discuss two broad ways one could relax the normative views supporting the longtermist thesis [...]

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Outline:

(00:11) Abstract

(01:22) 1. Introduction

(10:28) 2. The (determinative) unawareness challenge to longtermism

(15:08) 2.1. Unawareness importantly differs from mere uncertainty

(26:56) 2.2. The challenge of assigning utilities to unknown long-term outcomes

(37:41) 3. More promising avenues for rescuing longtermism in the face of unawareness?

(47:09) 4. Conclusion

(52:59) Acknowledgments

(54:06) Note for the jury of the Essays on Longtermism competition

(54:30) References

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Narrated by TYPE III AUDIO.