Comment by Cogito | Hacker News Reader

Comment by Cogito | Hacker News Reader

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> We haven't found that, and apparently aren't even close.

We do have ideas! Specifically, within the RNA world hypothesis, the transition period is called the virus world [0]

> given all the incredibly, insanely, unbelievably rare DNA sequences that exist in the world today,

We have a good understanding of where diversity comes from, I'm not sure what point you're making here.

> why is such a fundamental process not abundant as fuck already. Where'd it go? Why is this even a mystery?

I don't think anyone thinks this process need be 'fundemental', though it definitely is pivotal. It only really needed to happen once, and then DNA was off reproducing and spreading by itself. That said, it looks like viruses converting RNA to DNA could still be happening today.

In general, we don't expect novel self-reproducing molecules to arise today, because they are out-competed by existing self-replicating molecules. In a world where nothing is replicating the first replicator is king. In today's world a brand new replicator is food for something else.

> Maybe it's possible that your romantic view of how this all happens (pseudo-Darwinian circa 2020) isn't telling the whole story?

I don't think I, or anyone else really, is claiming to tell the whole story - just that we have good reason to believe this came about through physical processes, and no evidence to believe... well I'm not sure what else there could be.

What are you proposing?

[0] https://en.wikipedia.org/wiki/RNA_world#Evolution_of_DNA

Interesting discussion. I’d like to ask a sincere question:

Wouldn’t a system A that is capable of encoding another complex system B, need to be as complex in order to encode all the information in the result?

It’s like a compression algorithm, you can encode the information, but the complexity level of that information is still there (also the difficulty in compressing the information increases very fast - exponentially or maybe even factorially).

So if the most basic protein sequence requires so many bits of information, wouldn’t anything capable of producing that (in a non-random manner) also require at least that level of information (if not more).

It doesn’t matter what process we call systems A and B.

So it seems if randomness doesn’t solve the problem (because math), then the only conclusion is that there is a fundamental requirement for intentionality.

It's possible for a simple thing to encode something more complex, deterministically.

The prime example is The Game of Life - simple rules from which complex behaviour emerges.

This idea of information is one we're putting onto the system, not some inherent attribute. Yes, the encoding of a protein needs to have enough information to produce that protein (or a family of proteins), but that says nothing about the process that created the encoding.

For example, a strand of RNA can be spliced in many different ways to create many different proteins [0] and this process can go weird in many ways. New sequences will arise from this process, even though they weren't 'intended' to.

[0] https://en.wikipedia.org/wiki/RNA_splicing

Yes, and useful proteins are basically the equivalent of "oscillators" or "spaceships" in the game of life. But must runs of the game of life are not oscillators or spaceships, just like most proteins are useless.

That's why the "initial condition" is so important, and why DNA is so important: without a good "start state", you get useless results—just like in the game of life.

What we are trying to find is not Conway's rules for the game of life, but this: how do we produce useful starting states (DNA) with a physical system? And more importantly, how do we create those starting states preferentially (i.e. non-randomly)?

We still need a model for how useful DNA (which corresponds to the "initial state" in the game of life) gets created. And we have no model for that right now, other than assuming unique random initial states are continually occurring and letting the law of large numbers eventually "find" winners.

Minor side note, but most runs of the game of life actually will produce spaceships and/or oscillators, even starting from a random configuration. (Initialize a 100 x 100 box of cells randomly, and you're virtually guaranteed to get several gliders flying off of the resulting mess.)

For DNA, at least, it could have come from RNA (as per the link in my last post).

While I don't think the pre-biotic problem is solved at all, we have a lot more models of how it could have happened than you seem to credit - this is after all a huge research area.

For example, here is one [0], and here is a whole journal issue on the subject [1].

I found these by searching for 'evolution of DNA' and 'evolution of RNA'.

Now, these models all include some randomness, but in no way does anyone assume "unique random initial states are continually occurring... letting the law of large numbers eventually "find" winners"

The models show plausible environments where pre-biotic synthesis of RNA (or RNA pre-cursors) can occur, and stabilise.

This model you keep bringing up - randomly selecting a molecule from all possible combinations of atoms and saying 'enough time will get you one that works' - is not mentioned anywhere that I have seen. Perhaps some lay-people (of which I am definitely one!) believe it, but as you point out it is so obviously implausible it falls down on first inspection.

There are other models (lots of them!) and they don't rely on this pure randomness.

[0] https://phys.org/news/2018-01-chemical-evolution-dna-rna-ear...

[1] https://www.mdpi.com/journal/life/special_issues/evolution-R...

The Game of Life doesn't produce complex behavior from simple rules.

The complex behavior comes from a large enough random starting state combined with a very low minimal required complexity to see something interesting. Also, even for a short interesting run of local behavior, the game never produces a stable behavior that grows in complexity beyond the initial information encoded in the random state. (i.e. if there is a bubble of cool stuff happening somewhere on the 2d plane, something usually interferes with it and destroys that pattern - like waves in the ocean, even when the energy curves combine to form a wave once in a while, they are limited and temporary).

So the Game of Life is actually an example that the system is limited to the information encoded in the initial starting state.

In the starting state there is either:

- a large enough random search space (i.e. a million random attempts with a 100x100 board might get something cool looking)

- intentionality (a person can design a starting state that can produce any possible stable system)

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