Mass Extinctions

[RandomGuyOnCouch]

And it is. "Random" is the term we use to describe something sufficiently complex.

Random is the term we use to describe something statistically indeterminate, doesn't necessarily have to be complex.

Again, sufficiently complex. Something is 'indeterminate' if you can not work in all the variables and reach a conclusion, not because there is no determinable conclusion.

There are surely times when enough data cannot be collected, analyzed, or understood, but that doesn't mean that true randomness simply does not exist.

[Trolldor]

Well, it would be nice to find it.
Haven't yet.

[Ronja]

I agree that you won't know who/what will emerge from a mass extinction, but I don't know that this is at all surprising. Probably a paper written because the dude needed to publish something, and moved along the peer review process because there was nothing seriously wrong with it. Papers like that are good for giving someone else a chance to say "Oh, yeah?" and add another paper to their credits.

In a way I agree with that assessment, and in a way not. If the journalist at Wired (Brandon Keim) got it at all right, the dominating view of evolution among these statistics-focused dudes ("headed" by paleontologist Jack Sepkoski) has been that the long-term speciation results of a mass extinction event are calculable, predictable. That assumption is what this new dude, paleobiologist John Alroy, is questioning. And the reason he managed to get his article all the way up to Science, the one of the giant Siamese twins of peer-reviewed scientific publishing (the other one being Nature), is, IMO exactly that he is questioning a well-accepted and much used model.

Sepkoski ... also proposed that, by looking at the rate at which each group produced new species, one could predict the winners and losers of each mass extinction’s aftermath. Groups that diversified rapidly would flourish. Their destiny was already established.

“It’s a clockmaker vision of evolution. Each group has fixed dynamics, and if there’s an extinction, it just messes it up a bit,” said Alroy. “That’s what I’m challenging in this paper. There are limits, and that’s why we don’t have a trillion species. But those limits can change."

If I read the following correctly, Alroy worries about a cavalier attitude to the now happening mass extinction, which could be (very unscientifically) paraphrased as "nature will find a way to fix humanity's cock-ups, in a way that is pleasant enough for humanity."

Enough pieces have come together for Alroy to speculate on his findings’ implication for the future, given that Earth is now experiencing another mass extinction...

In the past, many evolutionary biologists thought life would eventually recover its present composition, said Alroy. In 100 million years or so, the same general creatures would again roam the Earth. “But that isn’t in the data,” he said.

Instead Alroy’s analysis suggests that the future is inherently unpredictable, that what comes next can’t be extrapolated from what is measured now, no more than a mid-Cretaceous observer could have guessed that a few tiny rodents would someday occupy every ecological niche then ruled by reptiles.

“The current mass extinction is not going to simply put things out of whack for a while, and then things will go back to where we started, or would have gone anyway,” said Alroy. Mass extinction “changes the rules of evolution.”

I don't like that last sentence (quote), because it is so vague, but I think if one looks at the Wired article as a whole, Alroy has a point. Will need to dig up the actual peer-reviewed article in Science to say anything more profound (and I don't have the time to do that now, so if anyone else has access to a campus license or something - hint, hint, nudge, nudge)...

[hackenslash]

Because Feynman explained the interference pattern by saying that paths that go through one slit interfere with paths that go through the other, if you turn on a light to determine which slit the particles pass through, thereby eliminating the other option, you will make the interference pattern disappear. And, indeed, when the experiment is performed, turning on a light changes the pattern...

(pg 81)
Omitted references to diagrams.

From Stephen Hawking's new book.

A particle exists in every possible history at the same time, which is why it can 'interfere' with itself, but if you observe it you determine which system history it takes, thereby eliminating both the interference and every other history.

As I thought, a misunderstanding of the observer effect. This doesn't actually take into account what constitutes an 'observer', which can also be a particle. We don't determine history as we observe it, history just is. On macroscopic scales, the vast majority of particles are being constantly observed by other particles, thus collapsing the wavefunction. Interpreting the result as our' determining history by our observation' on this scale amounts to quantum woo.

[Trolldor]

What part about 'turning on a light changes the pattern' do you not get?
That is directly influencing through observation.

And it is impossible to observe something without interacting with it.

[hackenslash]

What part about 'turning on a light changes the pattern' do you not get?
That is directly influencing through observation.

And it is impossible to observe something without interacting with it.

I do get it. Which bit of 'a particle constitutes an observer' do you not get?

[Trolldor]

You made a presumption and you missed the point.
When you get on track let me know.

[hackenslash]

No, I made a presumption and you confirmed it.

[RandomGuyOnCouch]

Well, it would be nice to find it.
Haven't yet.

Not necessarily true. You have referenced complex systems as having unknown deterministic variables or simply too many variables to keep track of. Could also simply be a true random in which case it has been found but, because it cannot be proven an unknown variable does not exist, it can't be verified as a true random.

[Trolldor]

In other words, "It would be nice to find it. Haven't yet."

[RandomGuyOnCouch]

In other words, "It would be nice to find it. Haven't yet."

Right, you could say that. Or you could be accurate and say "may have already found it, no way to verify, though".

[Svartalf]

I agree that you won't know who/what will emerge from a mass extinction, but I don't know that this is at all surprising. Probably a paper written because the dude needed to publish something, and moved along the peer review process because there was nothing seriously wrong with it. Papers like that are good for giving someone else a chance to say "Oh, yeah?" and add another paper to their credits.

Then why does Wired pick it up as if it's news? Is there so little happening in the tech world these days?

Or maybe the author of that paper just slept with the editor...

[Svartalf]

If the people disappeared, leaving the humans behind, this place would be much nicer.

mmmh... there probably not be enough umans left to populate and support a fair sized city

[Trolldor]

In other words, "It would be nice to find it. Haven't yet."

Right, you could say that. Or you could be accurate and say "may have already found it, no way to verify, though".

Not accurate at all, actually. No evidence to support this position.

[RandomGuyOnCouch]

In other words, "It would be nice to find it. Haven't yet."

Right, you could say that. Or you could be accurate and say "may have already found it, no way to verify, though".

Not accurate at all, actually. No evidence to support this position.

You find some giant fossilized bones. Do you 1) conclude that dragons are real, 2) extrapolate an evolutionary theory explaining dinosaurs, or 3) conclude that you found some giant bones and leave it at that?