[ExI] [Extropolis] Crosspost

[Keith Henson]

On Tue, Apr 15, 2025 at 4:58 AM John Clark <johnkclark at gmail.com> wrote:
>
> On Mon, Apr 14, 2025 at 3:43 PM Keith Henson <hkeithhenson at gmail.com> wrote:
>
>> > If you read the article, you seem to have missed that the 300-meter
>> sphere was a civilization, the brains were 10 cm cubes per Eric Drexler.
>
>
> I don't think it makes sense to hypothesize about the brain activity of millions or billions of separate individuals being computed inside a sphere of 300 meters.

Try reading it again.  Only the surface had uploaded humans, 100 to
the square meter.  The reason for the shape was the water flow for
carrying off 20 kW of waste heat from running a brain simulation at a
millionfold.  The reason for the size limit was to keep subjective
communication delays no worse than what we have on Earth.

> If there was an extremely fast and astronomically wide communication channel between your brain and mine so that every thought I had you had and every thought you had I had then we would stop being separate people, only Keith Clark (or John Henson) would exist.

You are assuming something that is not in the design.  On a subjective
basis, the communication needs to be no faster or more bandwidth than
we use today.  You don't merge with someone by watching their youtube
video or talking on the phone.  Of course you could, but that was not
in the physical design which is about communication delay and waste
heat problems of running fast.

But while I think the physics works for a million to one speedup, if
what we see at Tabby's star is data centers with trillions of uploaded
aliens, they did not take the speedup route.  If they had we would
never see them.  Whatever, data centers or dust, the light blockers
are 1.5 light seconds across.  I have posted the math on the Exi list
if you want to check it.

Keith

>  John K Clark    See what's on my new list at  Extropolis
>
>
>
>
>
>>
>>
>> >> > The problem is that the faster you run your brain, the more the world around you seems to slow down. With only a modest speedup, movement would seem like wading through molasses.
>>
>>
>> > That depends, interesting phenomena occur at all times scales. Even if your brain was sped up by a factor of a million billion, many particle physics phenomena would still seem to occur virtually instantaneously.
>>
>> >>  > For a million-to-one speedup, that means that all the communicating nodes can be no more than 300 meters apart,  i.e., configured as a sphere 300 meters in diameter with a hole to pump water in or out (for cooling). The area of the sphere is ~283,000 square meters.
>>
>>
>> > In previous posts I have given my reasons why I don't think a brain would be limited to a sphere of only 300 m in diameter, but even if it is that works out to be a volume of about 14,000,000 cubic meters. The average human brain is about 0.00135 cubic meters. And the signals in the human brain travel between 0.5 and 120 meters per second depending on if the axon is myelinated or unmyelinated. The speed of light is 300,000,000 meters per second.
>>
>>
>> >>  > One consequence that Eric Drexler discussed in Engines of Creation (end of Chapter 5) was a million years of science and engineering being done in one year. He didn’t discuss the subjective effect of a whole society uploading and subjectively experiencing a million years per calendar year.
>>
>>
>> > To GPT, Claude or Gemini it may seem like it's taken a million years to reach superhuman intelligence, but that doesn't mean we humans won't experience a superhuman AI before the end of the Trump administration.
>> >
>> >    John K Clark    See what's on my new list at  Extropolis
>>
>> > > 1) The maximum time it takes to send a message from one side of the brain to the other is NOT the only factor, another factor that is just as important if not more so is the bandwidth of that message channel; and for Mr. Jupiter Brain that bandwidth would be many billions or trillions of times wider than any biological brain has.
>>
>> > > 2) Mr. Jupiter Brain wouldn't need to use His entire brain for simple tasks, such as finding the integral of a 4D tensor equation, He would probably not be consciously aware of the steps He used to find it nor would He need to be, for Him the answer would just be intuitively obvious. In the same way a baseball player is not consciously aware of the steps his brain used to figure out the split second when he should start to swing his bat, he swung it when his intuition told him the time was right.
>>