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You could just as well say that the cosmic ray pions are more likely to destroy right-handed DNA, which would have the opposite effect. And I don't think essent

You could just as well say that the cosmic ray pions are more likely to destroy right-handed DNA, which would have the opposite effect. And I don't think essential mutations were particularly hard to come by in the primordial soup. UV light works fine, as do many, many chemicals. Or just more-primitive copying machinery. I don't think this weighs very heavily against the random symmetry-breaking hypothesis.

SideburnsOfDoom 4y ago
> You could just as well say that the cosmic ray pions are more likely to destroy right-handed DNA, which would have the opposite effect. You could, and it's going to be one effect or the other that is stronger - One of the chiralities will have an advantage due to this effect, relative to the other. And now we know which one.
- yyyk 4y ago
  >You could, and it's going to be one effect or the other that is stronger... And now we know which one. If the result would have been the other way around, we could have had here on NH the same story with the same argument with about the same conclusion. That's not very helpful. Note also the null hypothesis (none of these 'effects' matter, and choice is rather random) has the same non-explanatory potential as the story does.
thomastjeffery 4y ago
We already know the conclusion of this story: right-handed DNA is what exists today. The effort here is not to create a story blindly from known fundamentals into wherever that story might lead. The effort is to fill the gap in story from known fundamentals to a known conclusion. We don't know if other circumstances could have lead to another conclusion, and that would indeed be an interesting question to answer. But we do know that the conclusion we are living in somehow favored right-handed DNA. If this backstory leads to two potential conclusions - either left-handed or right-handed DNA, and not both - and we are already experiencing one of those conclusions (right-handed DNA), then it is OK for that backstory to be ambiguous. We don't need to prove the impossibility of the left-handed result. We only need to illustrate the impossibility (or unlikelihood) of both conclusions existing together at the end of the story.

SideburnsOfDoom 4y ago

> You could just as well say that the cosmic ray pions are more likely to destroy right-handed DNA, which would have the opposite effect. You could, and it's going to be one effect or the other that is stronger - One of the chiralities will have an advantage due to this effect, relative to the other. And now we know which one.

yyyk 4y ago
>You could, and it's going to be one effect or the other that is stronger... And now we know which one. If the result would have been the other way around, we could have had here on NH the same story with the same argument with about the same conclusion. That's not very helpful. Note also the null hypothesis (none of these 'effects' matter, and choice is rather random) has the same non-explanatory potential as the story does.

thomastjeffery 4y ago

We already know the conclusion of this story: right-handed DNA is what exists today. The effort here is not to create a story blindly from known fundamentals into wherever that story might lead. The effort is to fill the gap in story from known fundamentals to a known conclusion. We don't know if other circumstances could have lead to another conclusion, and that would indeed be an interesting question to answer. But we do know that the conclusion we are living in somehow favored right-handed DNA. If this backstory leads to two potential conclusions - either left-handed or right-handed DNA, and not both - and we are already experiencing one of those conclusions (right-handed DNA), then it is OK for that backstory to be ambiguous. We don't need to prove the impossibility of the left-handed result. We only need to illustrate the impossibility (or unlikelihood) of both conclusions existing together at the end of the story.