Saturday, January 14, 2006

Paul Davies clarifies the origin of life:

"All it takes to get life started is a quantum replicator - a process that clones bits of information attached to quantum systems by allowing them to interact with other quantum systems in a specific way. The actual system could be anything at all - the spin of an electron, a meta-stable atomic state, or a molecule that can flip between two conformations. The uncertainty inherent in quantum mechanics provides an in-built mechanism for generating variations."

Ahhh....that clears things up then!

15 Comments:

Blogger Lifewish said...

Seconded...

It really bugs me when people invoke "quantum did it" as a model of life's origins. Without a detailed description as to how this effect could arise, it's only one step above "Goddidit". I have yet to see such a description. We know that RMNS effects exist cos we've observed them, but I've yet to see any demonstration of quantum effects* in this context, and my personal guess is that biology is way too coarse to sustain serious quantum behaviour.

To the best of my knowledge, there are at least three convincing explanations as to how life could have emerged. This is not one of them.

* If anyone knows of such a demonstration, please tell

9:34 am  
Blogger Andrew Rowell said...

Lifewish,
You said:
"To the best of my knowledge, there are at least three convincing explanations as to how life could have emerged. This is not one of them."

What are your three convincing explanations?

9:40 am  
Blogger Lifewish said...

Well, they're basically oriented around which part of the cell evolved first. Option 1: it was self-replicating protein strands. This isn't as unlikely as it sounds - there do exist short self-replicating proteins, such as the 32-unit one mentioned here. As an added advantage, there are actually intermediate forms between self-replicating proteins and non-self-replicating ones, for example prions. This could provide the sloping golf course that would make things so much easier, although that's probably not necessary given how short the basic replicating chains are - it's a miniature golf course :)

Option 2: the chemical structure of the cell came first. This is the one that I understand least well, but it basically revolves around a set of equilibriating, mutually catalysing reactions (primitive metabolic pathways) getting set up - in a rockpool, say - and then "seeding" themselves. Eventually it would presumably be discovered that a cell-like structure was a good transport system. This model would incidentally provide a framework in which interesting protein or RNA chains would be a dime a dozen - they'd be constantly being created and broken down, until one finally appeared that could reproduce faster than it could be hacked apart. The golf course is still flat, but you'd be able to play two strokes a round rather than one*.

Option 3: the cell came first. Experiments that you can do in your home show that the sort of chemicals that would have been floating around in the primeval ooze (or probably foam - as happens today, gunk would have tended to collect at the seaside) are capable of forming primitive cell-like structures. These protocells, it has been discovered, form quite nicely around RNA chains, which would presumably protect the chain from being broken down. An element of competition enters the scene as RNA strands "battle" over the available lipids (for making the protocell) - some RNA strands are better than others at retaining lipids. My main concern here is that I can't see any way for the strands to become self-replicating - the golf course seems to slope towards the roughs rather than the hole.

My best guess is that no one of the above was uniquely responsible for life. At a guess, I'd say that protocells were the most likely first step, with the self-replicating proteins and metabolic reaction pathways hitching a ride between rockpools and eventually learning** to take good care of their hosts in the interests of colonising more and more rockpools. This would include copying the core RNA strand to ensure that the protocell was as stable as possible, so any protein that could do that would be very well placed to spread.

* I don't play golf, so apologies for any abuse of terminology

** Technically I should be sticking words like this in quotes because RMNS evolution is, of course, not intelligent. That's getting old quite fast though :) Any anthropomorphisation is not intended to imply intelligence, just its appearance.

11:46 am  
Anonymous Nathan said...

Will we ever really have a definitive idea for the origin of life by way of science? I mean, sure we can speculate on the 'primordial soup' and chemicals forming amino acids and such, but what about before that? I mean, science believes in a universe that is finite in its beginnings, so what was the transition from nothing to something? I don't see how science can even come close to speculating on the answer to that. If we have no naturalistic explanation, what other options do we have?

6:24 pm  
Blogger Lifewish said...

Will we ever really have a definitive idea for the origin of life by way of science? I mean, sure we can speculate on the 'primordial soup' and chemicals forming amino acids and such, but what about before that? I mean, science believes in a universe that is finite in its beginnings, so what was the transition from nothing to something?

I wouldn't tend to classify theories of the origins of the universe as being an "origins of life" issue - that way lies confusion. There's a couple of popular hypotheses about how the universe began. One is that it didn't - apparently, if you invoke imaginary (in the square root of -1 sense) time, you can get round the whole issue. I'm not completely sure I buy that though.

Another idea is that universes tend to bud off other universes - as black holes, maybe, or possibly even with the intervention of intelligent life. One interesting phenomenon of this is that, since universes could be expected to approximate the natural laws of their progenitor universes, there'd probably be an evolutionary pressure towards life-heavy universes. It's a cute thought. And, of course, since the universes are nicely walled off from each other, time probably doesn't need to be linear between them.

My personal belief is that at some point, with a few millennia of study behind us, we'll find out that the universe boils down to one equation and maybe a constant. Those two elements will in a sense be our universe. Our entire existence would be nothing more than the result of some cosmic Q&A session.

And maybe it's God doing the asking. Who knows?

1:48 pm  
Anonymous Nathan said...

Yes, sorry, what I meant to say was origin of the universe, and although its a bit off topic, we can't get to origin of life without going first through the origin of the universe.

"Another idea is that universes tend to bud off other universes."

Yes but this simply displaces the problem elsewhere, whether it arose "over there" or here does not really matter.

"My personal belief is that at some point, with a few millennia of study behind us, we'll find out that the universe boils down to one equation and maybe a constant."

I am not really so confident, I believe that this question is far beyond the realm of science, and no matter how much time passes, people will still ask this question. I mean, how is science supposed to determine how something arose from nothing? Because that is what it essentially breaks down to. I don't think that science is meant to answer this question.

5:22 am  
Blogger Andrew Rowell said...

I agree with you Nathan,
I think I said somewhere before...

You face a choice....either
Eternal self existent impersonal matter.
OR
An eternal self existent person able to make matter.

If you go for the first option then you have to believe in a mysterious process of entropy reversal.

11:06 am  
Blogger Lifewish said...

I pretty much completely agree with Nathan on this (in particular, my idea of how a universe starts is unconscionably fluffy). I would, however, add the caveat that an intelligent God is at least as improbable as spontaneously arising universes.

Andrew: What do you mean by entropy reversal, and how would nothing->God->World show less of it than nothing->World?

1:24 am  
Blogger Andrew Rowell said...

Lifewish,

I was not arguing for the nothing --> God step....and I don't know of anyone who would...indeed if "god" needed to begin then he would not really be "God"

It is either eternal God able to make matter from nothing
OR it is eternal matter.

If it is eternal matter then we need to explain why we are not in heat death.

8:49 pm  
Blogger Lifewish said...

I'm not sure quite what you mean by the "heat death" bit - iirc, we've got about 15 billion years before the Sun starts to balloon on us.

My point regards the probability of God is that, if we assume that an entity Just Exists, what're the chances of it turning out to be all-powerful, intelligent, benign etc? Without any sort of organising principle being applied to the entity (Gods presumably don't evolve significantly) the chances of our entity being like this are IMHO well below even the dodgiest calculations of the probability of abiogenesis.

Certainly the probability of an entity just happening to be intelligent, all-powerful, benign etc will be far far lower than, say, 1 in 100. Therefore, for it to be likely that such a God exists, we have to postulate that there are likely to be at least 49 other Gods that don't possess those qualities for each one that does.

This is precisely the sort of probability estimate that causes problems when trying to estimate how likely it is for a universe with our "fine-tuned" constants to emerge. There are, however, a couple of advantages that the latter has over the former. Firstly, there's nothing in science that prevents us from conjecturing the existence of billions of universes, whereas there's plenty in Christianity (for example) to prevent us from conjecturing the existence of billions of Gods.

Secondly, the existence of evolution as a concept suggests that, anywhere where self-replicating systems can form, "higher lifeforms" are likely to appear. This massively increases the size of the target that "blind chance" selection of universal constants has to hit - if they'd been slightly different, maybe it'd be an organised gas cloud typing this now. However, most religions I'm aware of would probably not be happy with the idea that, if things had gone differently*, God could be powerless or blind or mad or evil.

I guess what I'm trying to say is that "so who designed the Designer?" is indeed a legitimate response to the statement that a Designer is responsible for low-probability events - surely that Designer Himself will be equally low-probability.

On reflection, I can think of at least one explanation for how such a God could arise, but it would involve such a God not being timeless and wouldn't preclude an evil God in the least. I'd be interested to hear everyone else's explanations first.

* For some suitably timeless sense of "gone differently".

2:02 pm  
Anonymous Nathan said...

"I guess what I'm trying to say is that "so who designed the Designer?""

That still doesnt change the fact that there must have been a designer at one point in time or another. Its like asking where your lunch came from, and when I reply that the cook made it, you then ask me, well who made the cook? It doesnt solve anything.
A God is not something you can quantify, if someone made the God, well then he wouldnt really be God after all, would he?

This discussion is exactly why I think that this question is far beyond the realm of science. Already we are into philosophy and religion.

5:30 pm  
Blogger Lifewish said...

Its like asking where your lunch came from, and when I reply that the cook made it, you then ask me, well who made the cook?

Well, when a mummy cook and a daddy cook love each other very much...

The unnecessarily-sarcastic point being that we know perfectly well how the cook arose, thanks to the perpetual questioning of science. We know that two haploids fuse to form a zygote, we know an increasing amount about how the foetus develops from there, we know about the social and economic pressures that give someone an inclination to become, for example, a cook.

However, when we ask how the purported "Designer" of this system arose, and why He should fulfil certain criteria instead of the infinite number of other combinations of attributes that He could possess, there's nothing but silence. Given that a God exists, why should He display this particular set of behaviour patterns? It's as messy a question as asking why the universe should have a set of fundamental constants that permits life, and just as valid IMO.

The difference being that, in the case of the universe, we have some ideas as to how life could be plausible - ideas that would be mostly rejected if we attempted to apply them to God.

Note that I'm not saying that something made the God - I'm starting off with the assumption that such a God "just exists" and then trying to figure out what we can extrapolate about Him. The answer is "not a lot", hence the probabilistic mumbling.

Incidentally, can anyone provide me with a good reason why we shouldn't try to quantify God? The only one I can think of is "it might annoy him" but, since the judgement that such an attempt would annoy him is in itself a quantification of God's behaviour, I'm willing to take my chances.

2:02 am  
Anonymous Nathan said...

"Well, when a mummy cook and a daddy cook love each other very much..."

Ok, my initial point was that science cannot answer this question of the origin of the universe. We can't time travel back to see what happened so we speculate, so we guess. But when you get down to the very bare bones of the issue, we see that it is not a scientific question, it becomes a philosophical question.

I think my point about it not being a scientific question has been shown in this short discussion, as I said earlier, you have had to resort to lame, philosphical gesturings about the qualities of a God. You are not talking about science anymore here, and you are avoiding my initial statement about how science can possibly answer this.
I see there being two options, either there was a creator, or the universe is eternal. What is wrong with this kind of thinking?

5:54 am  
Blogger Lifewish said...

Ok, my initial point was that science cannot answer this question of the origin of the universe.

I'd agree completely that it can't do it directly. It may be possible to do it indirectly, or at least to demonstrate some way (like my "fundamental equation" conjecture) that the universe as we see it isn't really that improbable (on the assumption that universes exist). But you're right that this discussion has gone philosophical.

Sorry for side-tracking the conversation. I think I mistook something along the way for an introduction of the "we can't see how the universe could just exist naturally, so let's invoke a God" - apologies if this was a complete misinterpretation.

My argument then was that this is as much a displacement of the underlying problem (how can stuff, particularly complicated stuff "just exist"?) as the idea that universes bud off other universes.

2:20 pm  
Blogger beervolcano said...

You face a choice....either
Eternal self existent impersonal matter.
OR
An eternal self existent person able to make matter.


I doubt seriously that there can be "eternal matter."

But this webpage has some interesting stuff about heat death as it relates to the decay of the proton.

Some interesting lines:

The great British mathematical physicist P. A. M. Dirac noted the curious fact that the ratio of the strength of the electromagnetic vs the gravitational force is approximately the same as the ratio of the radius of an electron to the radius of the Universe.

What the hell is the radius of an electron?

Gravity controls the size of the Universe while the electric force controls the size of the electron. The strength of the electric charge controls the life span of virtual particle-antiparticle pairs, while the strength of the gravitational charge controls the life span of the Universe - including, coincidentally, the half-life of proton decay. When g = c, as in the interior of black holes, these distance, time, and force scales are (locally) equal. In black holes, space collapses, time stands still, and proton decay is as commonplace as particle-antiparticle annihilation.

I think it's great how there are these geometric relationships between the electric force and the gravitation force and this all relates to how the universe behaves.

All I can say about whether there is an eternal "person" (made of what?) is well beyond the scope of science.

12:58 am  

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