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Claims, yes. But he doesn't claim it. He puts it forward as a hypothesis. All useful hypothesis are, by definition, extra-ordinary.

by mr_luc 13y ago

a-priori 13y ago
Of course. It was the phys.org post which invoked Sagan's quote, and I was merely reusing it for rhetorical effect.
- mr_luc 13y ago
  Yeah - but there is a real distinction between theory and hypothesis, which that guy is probably acutely aware of. (Cmd-F on one page of his site shows the word hypothesis used 17 times). Reading a bit more, it seems like he's got expertise in a corner of science that could be relevant to what the article calls 'morphological change': "As the increasing apparent, magnificant, speed with which morphological change can occur continues to present itself for us to comprehend, the standard theory of random mutation followed by slow environmental selection, seems to stall. In my own opinion, female choice ... , but other mechanisms of mutation ... , now need to be considered anew. The role of hybridization in driving morphological change, as McCarthy has observed time and time again, particularly in his studies of avian species ... , may be the most powerful mechanism of all." Okay, so if the "speed of change" problem is a pretty wide-open question without a lot of firm answers, and if this guy has staked out a claim in the problem space ... my reaction is basically "good on ya'!" Go play god with interspecies breeding and come back in 5 years with an update. :)
- mistercow 13y ago
  >Sagan's quote Minor nitpick, but while Sagan popularized the saying, it probably originates with Laplace's "The weight of evidence for an extraordinary claim must be proportioned to its strangeness" (which is itself a rephrasing). This makes sense in historical context; the quote comes from 1814, two years after Laplace published the most well-known formulation of Bayes' theorem, which is exactly what the saying embodies.
mistercow 13y ago
>All useful hypothesis are, by definition, extra-ordinary. Not in the sense of that applies to that saying. In this context "extraordinary claim" means "claim with a very low prior probability". The saying can be expressed more precisely as "in order to upgrade to the level of expectation a hypothesis with a very low prior probability, it is necessary to make an observation of very low probability generally, but high probability given that the hypothesis is true." In other words, it's essentially just Bayes' theorem. And by no means are very-low-prior hypotheses inherently more useful. Certainly they have more impact than higher-prior hypotheses if they are validated, but in general, a very low prior means that a hypothesis is not worth wasting time considering. In some cases, a hypothesis can be so extraordinary that it becomes practically impossible to verify by experiment. In this case, for example, the hypothesis is so unlikely that it is quite difficult to imagine an experiment (or set of experiments) whose outcome was so unlikely that it would actually make us expect that humans were descended from ape-pigs.

Claims, yes. But he doesn't claim it. He puts it forward as a hypothesis. All useful hypothesis are, by definition, extra-ordinary.

by mr_luc 13y ago

Claims, yes. But he doesn't claim it. He puts it forward as a hypothesis. All useful hypothesis are, by definition, extra-ordinary.

a-priori 13y ago

Of course. It was the phys.org post which invoked Sagan's quote, and I was merely reusing it for rhetorical effect.

mr_luc 13y ago
Yeah - but there is a real distinction between theory and hypothesis, which that guy is probably acutely aware of. (Cmd-F on one page of his site shows the word hypothesis used 17 times). Reading a bit more, it seems like he's got expertise in a corner of science that could be relevant to what the article calls 'morphological change': "As the increasing apparent, magnificant, speed with which morphological change can occur continues to present itself for us to comprehend, the standard theory of random mutation followed by slow environmental selection, seems to stall. In my own opinion, female choice ... , but other mechanisms of mutation ... , now need to be considered anew. The role of hybridization in driving morphological change, as McCarthy has observed time and time again, particularly in his studies of avian species ... , may be the most powerful mechanism of all." Okay, so if the "speed of change" problem is a pretty wide-open question without a lot of firm answers, and if this guy has staked out a claim in the problem space ... my reaction is basically "good on ya'!" Go play god with interspecies breeding and come back in 5 years with an update. :)
mistercow 13y ago
>Sagan's quote Minor nitpick, but while Sagan popularized the saying, it probably originates with Laplace's "The weight of evidence for an extraordinary claim must be proportioned to its strangeness" (which is itself a rephrasing). This makes sense in historical context; the quote comes from 1814, two years after Laplace published the most well-known formulation of Bayes' theorem, which is exactly what the saying embodies.

mistercow 13y ago

>All useful hypothesis are, by definition, extra-ordinary. Not in the sense of that applies to that saying. In this context "extraordinary claim" means "claim with a very low prior probability". The saying can be expressed more precisely as "in order to upgrade to the level of expectation a hypothesis with a very low prior probability, it is necessary to make an observation of very low probability generally, but high probability given that the hypothesis is true." In other words, it's essentially just Bayes' theorem. And by no means are very-low-prior hypotheses inherently more useful. Certainly they have more impact than higher-prior hypotheses if they are validated, but in general, a very low prior means that a hypothesis is not worth wasting time considering. In some cases, a hypothesis can be so extraordinary that it becomes practically impossible to verify by experiment. In this case, for example, the hypothesis is so unlikely that it is quite difficult to imagine an experiment (or set of experiments) whose outcome was so unlikely that it would actually make us expect that humans were descended from ape-pigs.