<div dir="auto"><div><br><br><div class="gmail_quote"><div dir="ltr" class="gmail_attr">On Sun, Apr 23, 2023, 1:32 PM spike jones via extropy-chat <<a href="mailto:extropy-chat@lists.extropy.org">extropy-chat@lists.extropy.org</a>> wrote:<br></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><br>
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>...> On Behalf Of Ben Zaiboc via extropy-chat<br>
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>...At some point, surely, someone will start getting plausible answers to questions like 'How do we achieve practical fusion power plants/space-based solar power/drexlerian nanotechnology/mind uploading/indefinite life-extension/abundance economy for those who want it/give everyone in the world a chance to lead the lives they want to lead while simultaneously preventing any megolomaniac fuckheads wiping us all of the face of the earth, etc.?...I mean, what's the point of a superintelligence if it can't help with any of those? Ben<br>
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Thanks Ben, great introduction for me to restart a discussion we had for years in this forum, and ask for new insights from the GPT jockeys among us please.<br>
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When he was still with us, Robert Bradbury used to come to the west coast periodically and work with me on the mechanical details of Matrioshka Brains. I am sorry to report that since he passed on, I have made little progress on the idea. My last formal presentation on that topic for an engineering group was made in 2011.</blockquote></div></div><div dir="auto"><br></div><div dir="auto">Do you have a copy of this available online? I am interested.</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> I do not know if anyone has worked on the idea since then, as I have been caught up in real-world matters such as parenthood.<br>
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Question for our GPT hipsters please, or anyone else who wishes to comment:<br>
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Given a Matrioshka Brain ring with each processor consuming the power which can be generated by 100 cm^2 of solar cells at 1 AU (we can go with about 20 mW as a reasonable conservative estimate (well below the record with current technology))</blockquote></div></div><div dir="auto"><br></div><div dir="auto">Isn't incident solar radiation at 1 AU around 1300 W? 100 cm^2 should have 13 W available. I'm just making sure I'm not missing something, not sure why your estimate is 3 orders of magnitude less than my rough estimate.</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> with a minimum latency between adjacent nodes of about 3 microseconds,</blockquote></div></div><div dir="auto"><br></div><div dir="auto">A node here is a processor/solar cell pair? If so they should be ~10 cm from each other. At c the latency would be 3 nanoseconds rather than microseconds, but I think I am missing something.</div><div dir="auto"></div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> with a cell-phone-ish 256GB of on-board memory per node, and given a trillion such nodes, can we park an effective GPT-4 chatbot on that? </blockquote></div></div><div dir="auto"><br></div><div dir="auto">GPT-4 has a trillion parameters. At 8 bits per parameter you should be able to park it across 4 such nodes.</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> <br>
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What I have described in the paragraph above is the most recent (about 2016-ish) BOTEC design of a single ring of a Matrioshka Brain. </blockquote></div></div><div dir="auto"><br></div><div dir="auto">I would tend to think a civilization able to build one would be able to achieve computational substrates much closer to the maximum theoretical physical limits.</div><div dir="auto"><br></div><div dir="auto">My last estimates on this (using 2020 numbers) was that we're about 10^34 away from the best physically possible computers. So Moore's law has another 115 years left to go.</div><div dir="auto"><br></div><div dir="auto">Using 2016 tech estimates for such megastructures, feels to me a bit like a 1910 estimate of how many bits we could store in the future given the constraints that forests impose on the number of punch cards we can make.</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Never mind the other rings for now, let's look at just one ring, for I am told GPT4 needs jillions of processors to do its magic, </blockquote></div></div><div dir="auto"><br></div><div dir="auto">So long as the memory is there, you could use a pocket calculator to run GPT-4. It would just take a long time to produce its response.</div><div dir="auto"><br></div><div dir="auto">Newer more efficient but slightly less capable GPTs can run on modern desktops with good graphics cards (perhaps needing a few hundred watts to run at acceptable near real time speeds.)</div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">and the thermodynamics problems with a Matrioshka Brain are far from resolved. </blockquote></div></div><div dir="auto"><br></div><div dir="auto">Isn't thermodynamic efficiency just a matter of the fraction of the sky filled with star vs. the fraction of sky with ~3K vacuum? If I remember correctly then a Dyson sphere can at best utilize 50% of the energy present in the solar radiation. A ring, assuming rings don't fill most of the sky (from the point of view of the node on the ring) should be able to use closer to 100%.</div><div dir="auto"><br></div><div dir="auto"><br></div><div dir="auto"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"> Robert and I never did agree on this while he was with us. But for one ring, we don't care about that open question. Thermodynamic details cheerfully available on request.<br></blockquote></div></div><div dir="auto"><br></div><div dir="auto">A single ring has as much space as it needs behind the ring for a long tail of a heatsink. I wouldn't imagine cooling a single ring would be much of a problem. But the temperature the computer operates at does set a floor on the efficiency of irreversible computations (by Laundauer's limit).</div><div dir="auto"><br></div><div dir="auto">Jason </div></div>