4 ms·

Can you give an example of a falsified result?

sgt101 8y ago
All swans are white. I can sit for day after day not observing a black swan. This proves nothing, it does not prove the theory "there is no non white swan". But if I see a black swan then the theory that all swans are white is up the chute.
- madhadron 8y ago
  There's a distinction here. An experiment may measure a parameter to be zero instead of some nonzero value that everyone expected. That isn't subject to the black swan fallacy. Only when you are sampling is the black swan fallacy relevant.
  - sgt101 8y ago
    Yes agree, although the mechanism of measurement is important.
- pbhjpbhj 8y ago
  Hypothesis 0 - all adult swans have largely white plummage. Expectation - all observed swans "are white". Observation - some swans "are black". >"Nothing is falsified by the failure of an experiment to observe the expected." // The experiment failed to observe the expected. The hypothesis was falsified. Hypothesis 1 - all swans are white or black. --- Even with something like "we expected to find a Top quark at ~100GeV and found nothing" then the experiment has falsified that there is Top that would appear in such an experimental framework. We usual project that result beyond it's technical bounds, to say there is no top below that limit, is that what you're trying to get at? If you mean experiments aren't perfect then I don't see how that truism is useful. There have been a couple of potentially massive results in recent years that have fallen to poor experimental process.
  - sgt101 8y ago
    When a particle is observed at some energy the theories that predict that no such particle can exist are invalidated. It fault of the experiment to see something is just that, the experiment has failed. The causality of the failure is unknown, also if you do make the observation then the causality of the observation if unknown; Newton's observations and all the observations made by people who believed in a Newtonian universe were not unobserved when relating came along. I believe that the probabilistic approach to observation and observe to rule out approach in HEP now is a big error.
- jerf 8y ago
  The problem here is that in Aristotelian logic, which deals strictly in statements that are true or false and nothing in between, non-existent evidence is not evidence of non-existence. But this cute phrase, over-quoted and generally badly misunderstood, is not true because of the way the obvious, naive reasoning would lead you to believe... it is true because Aristotelian binary logic doesn't deal in anything like "evidence" at all. Non-existent evidence is not evidence of non-existence, because under this logic there is straight-up no such thing as evidence. There is only proof. However, while this form of logic is a great thing to teach children for their first (and likely only) one, and while your fancier logics probably ought to have some sort of Correspondence Principle for this style of logic, this rigid style of logic is not terribly useful in the real world, where statements of rigid, solid, 100%-confidence mathematical truth are in short supply. In any probabilistic logic, non-existent evidence is evidence of non-existence. It is not proof. But it is evidence. It is true the human mind may have a tendency to overweight the evidence, but that's fixed by math. So, while there is a sense in which the oft-trotted out phrase is true, in logics useful in the real world, it is simply false. After all... what other evidence of non-existence do you expect to gather? If you do not believe in the invisible, intangible unicorn that lives in your garage that Sagan liked to talk about, what other actual evidence for that belief do you have other than a complete lack of evidence it exists? There is no way for you to disprove it under Aristotelian logic. (And this style of logic doesn't have a great story for statements it can neither prove nor disprove, which is another reason why mathematics moved past it a long, long time ago.) If string theory is wrong, what other evidence for that can we gather other than the predictions of string theory being false? Remember, we can build physics models based on, say, Loop Quantum Gravity that excludes strings and may seem to predict the universe correctly, but that does not logically prove that there are not also strings in the universe. We exclude strings or other broken models only by consistently failing to collect evidence they are true.
  - sgt101 8y ago
    >>We exclude strings or other broken models only by consistently failing to collect evidence they are true Which is not a reason to consider them excluded. There is no reason to believe in the unicorn, or strings it there are powerful predictive alternate theories that explain the observed facts. But science creates contingent knowledge, not truth, that is all.
ncallaway 8y ago
The Michelson-Morely experiment is a famous experiment that pretty conclusively falsified the theory about aether. The experiment originally set out to detect and confirm the existence of the aether, but ended up falsifying the theory instead. https://simple.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment https://simple.wikipedia.org/wiki/Michelson%E2%80%93Morley_e...
- sgt101 8y ago
  So you disbelieve dark matter because it's not been directly observed?

All swans are white. I can sit for day after day not observing a black swan. This proves nothing, it does not prove the theory "there is no non white swan". But if I see a black swan then the theory that all swans are white is up the chute.

madhadron 8y ago
There's a distinction here. An experiment may measure a parameter to be zero instead of some nonzero value that everyone expected. That isn't subject to the black swan fallacy. Only when you are sampling is the black swan fallacy relevant.
- sgt101 8y ago
  Yes agree, although the mechanism of measurement is important.
pbhjpbhj 8y ago
Hypothesis 0 - all adult swans have largely white plummage. Expectation - all observed swans "are white". Observation - some swans "are black". >"Nothing is falsified by the failure of an experiment to observe the expected." // The experiment failed to observe the expected. The hypothesis was falsified. Hypothesis 1 - all swans are white or black. --- Even with something like "we expected to find a Top quark at ~100GeV and found nothing" then the experiment has falsified that there is Top that would appear in such an experimental framework. We usual project that result beyond it's technical bounds, to say there is no top below that limit, is that what you're trying to get at? If you mean experiments aren't perfect then I don't see how that truism is useful. There have been a couple of potentially massive results in recent years that have fallen to poor experimental process.
- sgt101 8y ago
  When a particle is observed at some energy the theories that predict that no such particle can exist are invalidated. It fault of the experiment to see something is just that, the experiment has failed. The causality of the failure is unknown, also if you do make the observation then the causality of the observation if unknown; Newton's observations and all the observations made by people who believed in a Newtonian universe were not unobserved when relating came along. I believe that the probabilistic approach to observation and observe to rule out approach in HEP now is a big error.
jerf 8y ago
The problem here is that in Aristotelian logic, which deals strictly in statements that are true or false and nothing in between, non-existent evidence is not evidence of non-existence. But this cute phrase, over-quoted and generally badly misunderstood, is not true because of the way the obvious, naive reasoning would lead you to believe... it is true because Aristotelian binary logic doesn't deal in anything like "evidence" at all. Non-existent evidence is not evidence of non-existence, because under this logic there is straight-up no such thing as evidence. There is only proof. However, while this form of logic is a great thing to teach children for their first (and likely only) one, and while your fancier logics probably ought to have some sort of Correspondence Principle for this style of logic, this rigid style of logic is not terribly useful in the real world, where statements of rigid, solid, 100%-confidence mathematical truth are in short supply. In any probabilistic logic, non-existent evidence is evidence of non-existence. It is not proof. But it is evidence. It is true the human mind may have a tendency to overweight the evidence, but that's fixed by math. So, while there is a sense in which the oft-trotted out phrase is true, in logics useful in the real world, it is simply false. After all... what other evidence of non-existence do you expect to gather? If you do not believe in the invisible, intangible unicorn that lives in your garage that Sagan liked to talk about, what other actual evidence for that belief do you have other than a complete lack of evidence it exists? There is no way for you to disprove it under Aristotelian logic. (And this style of logic doesn't have a great story for statements it can neither prove nor disprove, which is another reason why mathematics moved past it a long, long time ago.) If string theory is wrong, what other evidence for that can we gather other than the predictions of string theory being false? Remember, we can build physics models based on, say, Loop Quantum Gravity that excludes strings and may seem to predict the universe correctly, but that does not logically prove that there are not also strings in the universe. We exclude strings or other broken models only by consistently failing to collect evidence they are true.
- sgt101 8y ago
  >>We exclude strings or other broken models only by consistently failing to collect evidence they are true Which is not a reason to consider them excluded. There is no reason to believe in the unicorn, or strings it there are powerful predictive alternate theories that explain the observed facts. But science creates contingent knowledge, not truth, that is all.

ncallaway 8y ago

The Michelson-Morely experiment is a famous experiment that pretty conclusively falsified the theory about aether. The experiment originally set out to detect and confirm the existence of the aether, but ended up falsifying the theory instead. https://simple.wikipedia.org/wiki/Michelson%E2%80%93Morley_experiment https://simple.wikipedia.org/wiki/Michelson%E2%80%93Morley_e...

sgt101 8y ago
So you disbelieve dark matter because it's not been directly observed?