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Comment by simonster | Hacker News Reader

Let's assume that evaluating a program takes one microsecond and one atom, and that we can parallelize the search across every atom in the observable universe. If the AGI program is 500 bits long, it will take about 10^57 years to find by brute-force search.

There's a difference between ideas for which there is not enough compute right now and ideas that are computationally intractable according to our knowledge of the physical universe.

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Even more fun, I learned from Bruce Schneier's blog post [1] that it takes a minimum 4.4E-16 ergs of energy for an ideal computer running at 4.4K to "flip a bit" in an ideal setting.

Wolfram says there are roughly 2E76 ergs of mass-energy in the universe. [2]

So even if all matter and energy in the universe were put together to power a computer that did nothing but count upwards from zero, there's only enough matter and energy in our universe for the computer to count to about 10^91, or roughly 2^304 [3]. That's not even counting trying to use each resulting set of bits for anything.

So I don't think we'd be able to design too many useful computers by flipping bits until a useful algorithm comes out (at least not in this universe.)

[1] https://www.schneier.com/blog/archives/2009/09/the_doghouse_...

[2] http://www.wolframalpha.com/input/?i=mass-energy+in+the+know...

[3] http://www.wolframalpha.com/input/?i=log2(mass-energy+of+the...)

So, given the Shannon number, even the universe itself can't be used to brute force a game of chess.

Simulating evolution could also be called brute force. Doing that at a scale comparable to our own evolutionary history may be way out of range for present computers, but not foreseeable ones. (http://e-drexler.com/d/06/00/Nanosystems/ch1/chapter1_1.html) Likely we'll get there sooner in some not-quite-so-brutish way -- I'd hope so for ethical reasons -- but that way is available.

There is no reason to assume that evolution always brings about intelligent live. Anything "higher" on the ladder than bacteria could very well be an aberration that only arose due to very specific circumstances on prehistoric Earth.

I think we have more than a sample of one instance to look at though. The distinctive thing about humans is more that we operated collectively according to social rules, than pure intelligence.*

Due to evolution, the coordination of individual entities has happened repeatedly. Individual molecules became living cells, some suggest living cells merged into cells with mitochondria, viruses and cells merged, single cells merged into multicellular organisms, insects organized into social colonies, and now primates, i.e. humans have also organized into social colonies.

This doesn't prove evolution always creates social multicellular life, but it means (IMO) there is a clear pattern that provides a reason to assume it does short of specific reasoning or evidence about a barrier - why should the bacterial level be unique, and which bacteria would be the highest level?.

*I don't think you can separate intelligence from a social context. What we think of intelligence is closely related to things like the willingness to give up current rewards for long term ones. But it's not "smart" to do that unless you have justified faith that you live in a stable society where people are trusted to follow social rules.

There are a couple of most plausibly hard steps: the origin of life up to just before bacteria split from archaea, and the origin of eukaryotes, which happened just once after something like 2 billion years. But I had in mind something cheaper more like scaling up the idea of http://www.karlsims.com/evolved-virtual-creatures.html. Intelligence has evolved in animals as unrelated as octopi and us.

In an artificial setting you can manipulate the conditions to favour whatever you want.

FYI, we know what the theoretical physical bounds are:

https://en.wikipedia.org/wiki/Bekenstein_bound

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