20 Comments

I wonder if some people conflated:

How many "humans" do you think will ever exist?

with

How many "humans" do you think will have ever existed?

That would explain the 11-12 cluster as an anticipation of extinction.

Then the 12-13 has a longer human phase before evolving into another species that isn't human anymore.

And a third scenario where the civilisation stabilized towards valuing creating humans, and does so across the cosmos.

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A specific number wouldn't do justice to my credence and frequency distribution.

Plus, my uncertainty isn't just an epistemic one, but also a moral one. For example, I'm not sure whether I would count a Mati em-clade as 1 person or more.

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My best guess is 12-13 for "we call humans" (if there's a "biosingularity" or "Age of Malthusian Industrialism" scenario) and 20+ for "they call humans" (should either translate into a true singularity), but with <11 likeliest if Katechon Hypothesis is true (though I put only a low probability on that).

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For that to happen you would need to (1) universalize fertility restrictions below replacement and (2) maintain such a regime globally and indefinitely into the future. Tall call.

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Responses here give several people who could explain: https://twitter.com/robinha...

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Assume people live on average 80 years. Each year gives us 8bn/80 = 100mio people. Telomere erosion may make us die out in 4 million years. Average 2 mio years: 2mio * 100mio = 200 Trn potential But what is a human as we know it nowadays? I would say max 200k years so I get 20Trn

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On 2nd thought 100x current pop is too big for self destruction to be plausible. Instead let's try1') Destruction by non-rare aggressive rival civilization

..which admittedly begs the question why there is an "aggressive civilization rarity desert" between 1') and 2)

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My best shot at arguing for inherent trimodality: Squint your eyes and you can map the modes to the following scenarios:1) Self destruction in our technological infancy2) Deastruction by (rare) aggressive rival civilization3) We are alone in our Hubble volume

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Would you call yourself a Neanderthal? I wouldn't, although 23andme tells me I'm about 2% descended from them. I suspect the idea of "humanity" would seem similar to future human-descendants, under the most optimistic scenarios.

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Technology as we know it requires enormous amounts of fossil fuels; prior to the widespread use of coal, metal was expensive. Since practically all of the easily-accessible fossil fuels have been used, humans without advanced extraction technologies may not be able to start over. Fossil fuels recover so slowly that it's unlikely "human" would be a relevant concept when they return.

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There can also be a kind of post-industrial steady state reached with <0.2T, with humanity not going anywhere really beyond this planet. Getting biological humans to other stars will be difficult to say the least. Enormous amounts of energy will be required, this may be solved but the second resource is time, that one may never be solved. Living on other planets will be difficult, they may vary wildly in gravity, habitable zone, length of day, terraforming may be to time and resource consuming to be worth it. Humans are after all the highest animal adapted and a part of Earths ecology, we can't live somewhere else that is not highly adapted and modified to ourselves. Maybe something like Ringworlds or Orbitals here in the solar system, although it would have to be mini-orbitals as most science fiction mega structures are built out of unobtanium. The solar system may support a couple of trillion this way.

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I voted 0.1-1T WCH because I think we become posthuman by 2500. Hopefully human population can growth 0.5-1% till then, mostly off planet obviously.

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What's the scenario that gets you a "permanent" return to pre-industrial technology? If humanity still exists, in essentially any form, I don't see how you "permanently" constrain the future development of technology.

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Your #2 may correspond to the highest clump, but your #1 doesn't match the lowest clump. Killing ourselves in the next century would result clearly in <0.2T.

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That is true you would have to add a further criteria such as 'the largest set of individuals that are all reproductively compatible with each other that includes the present set.'

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One problem, or at least complication, with your model is that humanity can branch. So you can have multiple species at the late or final stages who cannot breed with each other, but are 'human'.

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