Quantum Evolution - Tilted Forum Project Discussion Community

CSflim · 06-28-2003, 07:07 AM

Science is pretty much in agreement that all life on earth evolved over billions of years from much simpler single celled organisms. What is less obvious is where this first single cell came from. No theory is of yet completely satisfactory.
Some people insist that this single cell was placed on earth by God, in the knowledge that it would evolve into all of the plants and animals that we see today. This however is obviously not a very satisfactory solution.
Other people claim that the single celled organism arouse by chance, from random chemical mixing from the primordial soup. The chances of this happening are admitedly astronomically tiny. Even given the immense vastness of the universe, it is still highly unlikely. Some make the point of the possibility of a multiverse, so that even though the possibility of life arrising in a single universe is incredibly unlikely, given a near infinitude of universes, it becomes plausable. the fact that we are hear to ponder this question is proof that we inhabit the incredibly "lucky" universe. Again this is not really a very satisfactory answer.
Another theory is that life evolved from unliving material. Material with the power to grow and to replicate its own structure is a possible ancesstor to this cell. I won't go into the details too much here, but this is actually a more reasonable argument than it may sound. The example of crystalline structures is a good one, which can take in the required elements from its environment (feed) and use these to replicate its own structure. The probelm with this theory is that there is very little evidence for it. Most notably, where are the border line lving/dead structures today?
The list of theories of the origin of the "proto-cell" go on and on. However, one very interesting theory is the idea of Quantum Evolution. I seems quite plausible. The following extract requires a basic grasp of the concepts behind quantum mechanics, most notably the inverse-quantum-zeno effect (it is however expalined briefly).

Quote:

Think about the multidimensional walk that led to the self-replicator. It should be familiar in that it strongly resembles the way the inverse quantum Zeno effect can direct a quantum system along a particular path. The inverse quantum Zeno effect represents one of the peculiarities of quantum measurement, whereby a dense series of measurements along a particular path can draw that system along that path. Insertion of extra polaroid lenses, between vertically and horizontally polarized lenses (a perpendicular or orthogonal pair) rotates the angle of polarization of light. Without the extra lenses, the distance between the two states (vertical and horizontally polarized light) is too great. No light gets through. But the insertion of the extra lenses - each performing a quantum measurement - lays down a series of stepping stones which rotates the light from one state (vertically polarized) to another (horizontally polarized) in a series of short hops. A sufficiently dense series of measurements will lay down a path that will allow the photons to evolve smoothly from one state into another. Similarly, a dense series of quantum measurements of a particle along a positional path can move the particle along that path. The path may be only one out of a trillion equally probable, but quantum measurement can force the system to evolve in that measured direction.

But isn't this more or less what we want to do when we evolve the single amino acid arginine (R), along a single path through peptide multi-dimensional space to synthesize the self-replicator, RMKQLEEKVYELLSKVACLEYEVARLKKLVGE? In classical terms, the probability of the peptide taking the right route is close to zero (in fact 1/10^32). But if quantum measurements were performed along the route, then the inverse quantum Zeno effect could make that path much more likely. Can the inverse quantum Zeno effect make the reaction more probable? To see how, recall how the inverse quantum Zeno effect actually works. It depends on the ability of oblique quantum measurements to decompose a quantum state into sets of orthogonal (perpendicular) states. Measurement then forces one of those states to become real, and a dense series of measurement forces the system along the measured path. The polarization state of photons can be rotated by the inverse Zeno effect, as can the position of particles. If positional measurements can be performed to move electrons around in empty space, they can equally be performed to move electrons (or protons) around in the space of atoms and molecules.

Coninued on next post. Damn 5000 characters post limit!

CSflim · 06-28-2003, 07:07 AM

Quote:

Looked at this way, the chemical reaction leading to the first self-replicator (or indeed any chemical reaction) becomes a sequence of electron and proton movements within and between molecules. The walk in multi-dimensional peptide addition space, that led to the self-replicating peptide, becomes a walk in position space for electrons and protons. The route to a single self-replicator will still be extremely improbable but quantum measurement and the inverse Zeno effect could capture the motion of the particles along that route and thereby make it more likely.

But how can the motion of particles, within and between molecules, be measured? Enzymes can perform that feat. The precise position and energy of particles within enzymes is crucial for their enzymatic activity. Enzymes regularly perform quantum measurements of the states of their own particles. I have already described how proto-enzymes would have inevitably emerged in the quantum peptide. The enzymatic actions performed by these proto-enzymes would have performed quantum measurement of the particles that make up those peptides. The proto-enzymes would have emerged unscathed from the measurement process and - after measurement - their quantum state would have drifted back into the quantum realm. However, any chain of electron and proton motion that led to a self-replicator would have been irreversibly amplified into the classical world. Although proto-enzymes may remain at the quantum level, a self-replicator inevitably amplifies its quantum state to the classical level. The self-replicator nailed the growing peptide to the classical world.

We are then left with a chain of quantum measurements terminating with a self-replicator that amplified the quantum system to the classical level. This is exactly analogous to the inverse quantum Zeno effect. Whereas, in the light and sunglasses experiment, we rotated the angle of polarization of light by quantum measurements performed by a series of polaroid lenses; in the quantum proto-cell, it was a series of proto-enzymes that performed the quantum measurements. In the light experiment, it was our observation of light passing through the horizontal lens that performed the final irreversible act of measurement which amplified the quantum system; but in the proto-cell, it was the emergence of the self-replicator that nailed the system to the classical world. The emergence of the self-replicator was the end of the line for the inverse quantum Zeno effect. Quantum measurements by proto-enzymes along the route to the self-replicator laid down a series of stepping stones that led to the emergence of life.

Only a few measurement steps would have been necessary to enhance significantly enhance the probability of generating the first self-replicator. Remember that a single Polaroid lens performing quantum measurement can increase the probability for photon transmission through a crossed lens system (combination of horizontal and vertical lenses) from zero to six per cent - an infinite increase. Even if only two or three steps along the path to self-replication were subject to quantum measurement, it may have been sufficient to raise the probability of our self-replicating peptide from 1/10^32, to a value achievable in a quantum proto-cell within a small warm primordial pond. In this guise, the inverse quantum Zeno effect performed a role later taken over by Darwinian natural selection. just as the evolution of the highly improbable structure of the eye was guided through the multiverse of design by natural selection's ability to capture beneficial mutations, so the evolution of the highly improbable self-replicator was guided through a prebiotic chemical multiverse by quantum measurement's ability to capture the quantum states which led to the self-replicator.

This comes from a book called Quantum Evolution - The new science of life by Johnjoe MacFadden. It is an excellent read, which requires no prior knowledge. The first half of the book briefly explains natural selection, genetics and quantum mechanics. It can be skipped if you are already familiar with these topics. The second half expalins how the effects of quantum mechanics may have played a major part in our evolution, explains modern experiments which back up the theory, especially the phenomena of "Adaptive Mutations". It also goes on to hypothesise about the role of quantum mechanics in our evry conciousness.

So what do you think about the extract? Any thoughts? I can post other extracts if anybody wants.

Jack Ruby · 06-29-2003, 11:49 AM

This is a little too technical for most people, I'm afraid. Or maybe I just didn't pay enough attention.

CSflim · 06-29-2003, 02:27 PM

Quote:

Originally posted by Jack Ruby
This is a little too technical for most people, I'm afraid. Or maybe I just didn't pay enough attention.

hmmm.... I guess your right! Still, nobody can claim I didn't try!

It is a pity really. Its a very interesting hypothesis. I guess I could paraphrase it, if I actually believed there were people who were interested.

guthmund · 06-29-2003, 08:58 PM

I like to consider myself a pretty smart fellow, but

Brain, hurt, must pass.....out

yatzr · 06-29-2003, 09:57 PM

wow, that's deep

Slims · 07-01-2003, 12:18 AM

This just sounds like the Anthropic Principle in it's strongest form.

CSflim · 07-01-2003, 06:20 AM

Quote:

Originally posted by Greg700
This just sounds like the Anthropic Principle in it's strongest form.

No, its very different from the anthropic principle. The anthropic priciple proposed that all of the states of a quantum superposition (and hence all worlds resulting) are equally real. This hypothesis proposes that quantum superpositions, evolve themselves into reality through peptides, then enzymes, and ultimately, life.
It dismisses the anthropic principle in favour of the decoherence principle. Once a quantum superposition is "measured", by its environment, it becomes decoherent and hence "real". The way the superposition IS measured, is when it is in the form of a peptide/enzyme.

stingc · 07-05-2003, 08:17 PM

I have a lot of comments on this, so here goes...

I see no reason that this requires invoking quantum mechanics. Quantum mechanical measurement arguments should be avoided in any complex situation, especially far away from zero temperature. None of it is very consistent (should I explain further?).

As far as I can tell, the author just is saying that the probability for some process is larger than the naive estimate because all paths are not equally likely. I don't see this as profound, and it doesn't require talking about quantum mechanics. I do agree with it though. Anyone who's ever played with chemistry should agree that there are good and bad ways of synthesizing things. Also, molecules with the same groups stuck in different places are not in any way "almost the same."

The probabilistic arguments that I have seen arguing that life shouldn't have been spontaneous are all bunk to me. Why? We don't know enough to make any reasonably estimate of the probability. Let's assume for simplicity that "life," whatever that will be defined as, is based on more or less the usual biochemistry we know about. This is a huge assumption, but everyone makes it.

Now what is the minimal starting point for life? People can maybe come up with individual possibilities, but nobody can describe the entire space of possibilities. It is irrelevant to say that something will only exist on one of 10^32 earths if there are 10^35 such objects that could spawn life. A lot of this problem is simply because we only know about the form of life that we have here. There are surely other possibilities that work on very different principles. All of this has to be included to produce a good answer.

Even if we could write down all of these possiblities, we'd then have to know all reasonable ways that each of them could be produced, and the probability for each path (they aren't equal!). I think this is impossible for practical purposes.

People generally go ahead and make up a number anyways, which I think this is dishonest. A random number is not better than saying "we don't have a clue."

stingc · 07-05-2003, 08:28 PM

CSflim, your definition of the anthropic principle is not the usual one. The standard definition is that it is just a general philosophy saying stuff is the way it is because we wouldn't be here if things were any other way. The multiple universe hypothesis is *an* anthropic principle, not *the* anthropic principle. I think Greg was referring to the less specific definition. Its just semantics though

06-29-2003, 11:49 AM	#3 (permalink)
Jack Ruby Psycho Location: Belgium	This is a little too technical for most people, I'm afraid. Or maybe I just didn't pay enough attention. __________________ You don't know what you don't know.

06-29-2003, 08:58 PM	#5 (permalink)
guthmund big damn hero	I like to consider myself a pretty smart fellow, but Brain, hurt, must pass.....out __________________ No signature. None. Seriously.

06-29-2003, 09:57 PM	#6 (permalink)
yatzr Insane	wow, that's deep __________________ Mechanical Engineers build weapons. Civil Engineers build targets.

07-01-2003, 12:18 AM	#7 (permalink)
Slims Eccentric insomniac Location: North Carolina	This just sounds like the Anthropic Principle in it's strongest form. __________________ "Socialism is a philosophy of failure, the creed of ignorance, and the gospel of envy, its inherent virtue is the equal sharing of misery." - Winston Churchill "All men dream: but not equally. Those who dream by night in the dusty recesses of their minds wake in the day to find that it was vanity: but the dreamers of the day are dangerous men, for they may act out their dream with open eyes, to make it possible." Seven Pillars of Wisdom, T.E. Lawrence

07-05-2003, 08:17 PM	#9 (permalink)
stingc Psycho Location: PA	I have a lot of comments on this, so here goes... I see no reason that this requires invoking quantum mechanics. Quantum mechanical measurement arguments should be avoided in any complex situation, especially far away from zero temperature. None of it is very consistent (should I explain further?). As far as I can tell, the author just is saying that the probability for some process is larger than the naive estimate because all paths are not equally likely. I don't see this as profound, and it doesn't require talking about quantum mechanics. I do agree with it though. Anyone who's ever played with chemistry should agree that there are good and bad ways of synthesizing things. Also, molecules with the same groups stuck in different places are not in any way "almost the same." The probabilistic arguments that I have seen arguing that life shouldn't have been spontaneous are all bunk to me. Why? We don't know enough to make any reasonably estimate of the probability. Let's assume for simplicity that "life," whatever that will be defined as, is based on more or less the usual biochemistry we know about. This is a huge assumption, but everyone makes it. Now what is the minimal starting point for life? People can maybe come up with individual possibilities, but nobody can describe the entire space of possibilities. It is irrelevant to say that something will only exist on one of 10^32 earths if there are 10^35 such objects that could spawn life. A lot of this problem is simply because we only know about the form of life that we have here. There are surely other possibilities that work on very different principles. All of this has to be included to produce a good answer. Even if we could write down all of these possiblities, we'd then have to know all reasonable ways that each of them could be produced, and the probability for each path (they aren't equal!). I think this is impossible for practical purposes. People generally go ahead and make up a number anyways, which I think this is dishonest. A random number is not better than saying "we don't have a clue."

07-05-2003, 08:28 PM	#10 (permalink)
stingc Psycho Location: PA	CSflim, your definition of the anthropic principle is not the usual one. The standard definition is that it is just a general philosophy saying stuff is the way it is because we wouldn't be here if things were any other way. The multiple universe hypothesis is an anthropic principle, not the anthropic principle. I think Greg was referring to the less specific definition. Its just semantics though