Series of absurd upgrades in nature's great search

post by lemonhope (lcmgcd) · 2023-09-03T09:35:20.760Z · LW · GW · 8 comments

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8 comments

So you want to find that special thing that replicates best and lasts longest? Just vibrate a bunch of molecules a long time!

You might reasonably assume that molecules wouldn't practically ever randomly assemble themselves into anything worth looking at. It happens a bit differently instead:

  1. Eventually, "solar systems" will form. Each one has an independent star (energy source) with several independent planets (experiment boxes) that vary in their temperature, mass, composition, etc dramatically. (Instead of just having a big homogenous soup throughout the universe with much less search power)
  1. A lipid layer boundary innovation thing leads to trillions of independent chemical experiments on some planets (instead of a big soup within each planet)
  2. A general protein factory is discovered. Critically, it uses a simple and concise and robust physical encoding scheme. This allows good bubbles from step 2 to copy quickly and exactly, and clear out weak bubbles faster.
  3. Very large multicellulared organisms make several search improvements: creatures can do sexual selection on each other instead of just getting random mutations; big smart fast predators can find & kill weak creatures quite effectively; parasites find weaknesses early & often. This all clears out weak replicators and leaves more room for the good ones.
  4. Some creatures develop language and culture, which isn't generally much use, except that it one day allows them to design new replicators from scratch.

So you really can just vibrate sand and get out all kinds of things!

A bit misleading to talk about nature's great search as natural selection via mutations+generations. It's actually much weaker (there is no algorithm or optimizer at all, only one long aimless physics sim) or uh much stronger (a five-level hierarchy having branch factor ~ 1 billion of experiments of different kinds).

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comment by Viliam · 2023-09-03T12:28:37.521Z · LW(p) · GW(p)

Also, Tegmark multiverse conveniently provides many causally isolated universes with different laws of physics, so that the above "too good to be true" conditions can happen in some of them.

Also, quantum physics: if you are not sure which random choice would lead to evolution of life, simply try both.

Replies from: lcmgcd
↑ comment by lemonhope (lcmgcd) · 2023-09-05T04:03:24.539Z · LW(p) · GW(p)

Do you personally believe in either of those?

Replies from: Viliam
↑ comment by Viliam · 2023-09-05T11:25:30.847Z · LW(p) · GW(p)

Ah, that's a difficult question. I don't think I will ever know for sure how this works. Smarter people than me will probably figure it out a few centuries after my death.

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I think that many-worlds interpretation of quantum physics or something similar is at least 50% likely to be true. By "something similar" I mean some version that says that superpositions never collapse, and multiple states have a symmetrical claim on being real -- that is, each of them is "real" from its own perspective, and the others are "not real" from its perspective, but everyone's perspective is like this, and from the "outside" there is nothing that makes one of them right and the others wrong.

That said, even if all quantum states are possible, some of them have greater measure than others. To translate it to sci-fi terms, you can have parallel universes, but some of them are "more real" than others. Like, each of them feels equally real "from inside", but there are different probabilities for ending up in one of them. Again, this is not about details, just the idea that: some things are more likely that others, the existence of parallel universes does not mean that you are free to throw away the laws of physics.

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With regards to Tegmark multiverse, my confidence is much lower. Unlike quantum physics, when we know for sure that superpositions exist at least temporarily (and at least like a mathematical metaphor), we have no experimental evidence about universes with other laws of physics, if such thing is possible. Also, it seems to answer some questions, but opens much more -- what kinds of universes are possible, and what is their relative measure? Can you imagine any laws of physics (maybe even logically inconsistent ones), or is it somehow limited to a certain type of laws? Are universes with less complicated laws of physics more likely; and if yes, how exactly do you measure the complexity? Unless we answer these questions, then even if we believe that universes with other laws of physics exist, it does not allow us to make specific predictions. A theory that doesn't make predictions is useless.

Like, when I try to think about this, it seems that the universe with the simplest laws of physics is... whatever is the simplest universal machine. Because it can run any other universe as a simulation. But this is also the least useful answer, because "our universe is simulated by a universal machine" tells you absolutely nothing about our universe. (Not even something like: "we should expect the laws of physics in our universe to be the most simple laws that allow existence of intelligent life". Because a universal machine can also simulate needlessly complicated universes.) Or maybe we should consider the complexity of the universal machine plus the complexity of the laws of the simulated universe? But then, the easiest recipe for simulation is "simulate all possible universes". Continue this way, and the "most simple" universe will be "a universal machine, simulating (among other things) a universal machine, simulating (among other things) a universal machine,...". Which doesn't actually seem simple to me.

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tl;dr -- quantum many worlds, probably yes; Tegmark multiverse, I have no idea

Replies from: sharmake-farah
↑ comment by Noosphere89 (sharmake-farah) · 2023-09-05T19:58:42.039Z · LW(p) · GW(p)

Unless we answer these questions, then even if we believe that universes with other laws of physics exist, it does not allow us to make specific predictions. A theory that doesn't make predictions is useless.

I tend to think that this is the biggest reason why despite thinking the Tegmark Multiverse theory is right, it ultimately sort of adds up to normality for most purposes, and why in practice it's not so useful for very much.

Replies from: Viliam
↑ comment by Viliam · 2023-09-06T11:16:08.325Z · LW(p) · GW(p)

Yes, knowing in detail how something adds up to normality, allows you to predict weird situations, or design experiments that go outside the normal. For example, understanding the "weirdness" of quantum physics on one hand doesn't change the everyday life; on the other hand it gives us quantum computers. Because we understand both how it is normal, and how to make it not-normal.

With Tegmark multiverse, we cannot even do experiments. At best, if we actually understood it deeply, we might be able to make better predictions about the laws of our universe. Maybe.

comment by Bayesian0 · 2023-09-09T16:32:02.756Z · LW(p) · GW(p)

Is it reasonable to talk like this, if talking about an implicit optimization algorithm? Especially if fitness is determined by environment and is evaluated immediately ( as in if a negative threshhold is passed, which is the complete absence of all instacnes of a gene, then the gene is out, until/if it remerges ), is my reasoning wrong?

Is there a reason that people often use sex or sexual selection as an example, I have seeen this quite some times now? Why is that important here? I am asking because it is used in "newcomer posts"/entry posts too, as in is it about mesa-optimization or crossover? Or is that rhetorical to achieve more exposure? I am asking because it is somewhat hard to interpret this pattern in a meaningful way, maybe there is no meaningful way.

I like the differentiation when explaining why evolution could be viewed as either efficient or inefficient.

comment by sithlord · 2023-09-06T13:19:01.981Z · LW(p) · GW(p)

you have forgot the most important part: https://en.wikipedia.org/wiki/Cosmological_natural_selection

which is supported by modern string theory ( a well kept secret among the experts)

Replies from: lcmgcd
↑ comment by lemonhope (lcmgcd) · 2023-09-06T17:06:58.884Z · LW(p) · GW(p)

What do you consider the strongest evidence / reason to believe?