His forthcoming book may be of interest to LWers: A Crisis of Faith: Atheism, Emerging Technologies, and the Future of Humanity. Mostly it's a beginner's book about atheism, but chapter 20 discusses cognitive enhancement and mind uploading, and chapter 21 discusses existential risks as one of the most important things for humans to address once they've stopped fooling around with religion. There's also an appendix on the simulation argument.
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