6 ms·

Physics and chemistry are pretty robust, everything else is far squishier. It's pretty easy to get identical atoms or molecules or subatomic particles. It's m

Physics and chemistry are pretty robust, everything else is far squishier. It's pretty easy to get identical atoms or molecules or subatomic particles. It's much harder to grow a field of identical plants or raise hundreds of identical mice.

analog31 10y ago
It's also harder to do things to plants and mice, much less humans, without knocking them so far out of balance that it ceases to be a meaningful experiment.
- jfarlow 10y ago
  That's a strong statement. I'd say it 'ceases to be trivially interpretable'. And I think this is part of where the 'the published paper said ___ so it must be true!' disparity between scientists and public becomes more apparent. In biology when you design a good experiment, run it, come up with a model that fits your experiment, no scientist would ever pretend that their articulated model was how things actually worked. It's close, it's reasonable, but many more publications would be needed to confirm it. A single publication just is not enough to decomplexify the entanglements in biology. Many other scientists will use that model as the basis for their newer experiment, and when their results do not comport, they alter, adjust, or if need be, discard the original model. The trouble with biology is it might take an entire 'Cell' paper (12 pages of dense publication - ie, many many grad-student-years of work) just to come up with the most simplistic model for what the biological experiment observed. That doesn't mean it wasn't meaningful - it was just much more complicated and less easily well-describable than physics and chemistry experiments. But very much like physics and chemistry, there is a definite trend towards a well-described and predictable system. Models actually get increasingly accurate over time. And this feature might be part of the border in defining a 'robust' science.
  - xaa 10y ago
    > just to come up with the most simplistic model Yeap. Bioinformatician here. Not only are most published models overly simplistic -- which everyone acknowledges -- but I think our bigger problem is we don't even have a reasonable "meta-model" of biology. What I mean by that is, imagine experiments were instantaneous and free. How would we then incorporate the results into a mathematical/computational/predictive framework that describes biological reality in a way analogous to physics? AFAIK, we haven't the foggiest clue. Biology is pretty theory-light and empiricism-heavy, probably because we have good results with things like "I dunno what this mold is secreting, but it seems to be killing the bacteria!" So our experimental results are pretty precise (although arguably not "robust" between strains/conditions/etc), when people bother to use n>3, but the models and theory are anything but.
- semi-extrinsic 10y ago
  > knocking them so far out of balance that it ceases to be a meaningful experiment Things in physics can sometimes be knocked so far out of balance during an experiment it boggles the mind, while still rendering perfectly sensible observations. E.g., I once heard the LHC described as "trying to determine how a grand piano works by throwing lots of them one after one down a very long set of well-defined stairs equipped with lots of very sensitive microphones and force sensors". In other cases, nothing could be farther from the truth. Say you are measuring heat transfer coefficients in high-Re laminar flow through a tube. A single 100-micron step imperfection in the tube wall will render your results pretty much useless. The distinguishing feature of physics is perhaps that one can know to a very high degree of precision before constructing the experiment which parameters/uncertainties it is very sensitive to.
0x445442 10y ago
Agreed, from a Physicist's perspective, Darwin's Theory is extremely "squishy".
- Luc 10y ago
  Nonsense.
- jon2k17 10y ago
  Could you expand on that?
- ealloc 10y ago
  My impression is that physicists who say this usually don't know much about the theory and evidence for evolution. (I am trained in physics, I now do biophysics). What about the beautiful and often very precise linear relationship between radioactive dating of the fossil record, and genetic dating using the molecular clock? What about the beatiful correspondence often found between the principle components of genetic variation and geographical position (isolation by distance)? What about all the biochemical discoveries related to DNA function (including the existence of DNA itself), how mutations occur, about heritability? What about everything we've discovered about genome composition and how it changes over time? (duplicate genes, pseudogenes, transposons, hotspots of various kinds). Is a DNA sequence less precise than a spectral line?
  - xaa 10y ago
    (Bioinformatics) I wonder if he means not that evolution is false/unfalsifiable/irreproducible, but that it is not really a very predictive theory. I agree there is a lot of evidence that it happened and continues to happen, but predicting how it will happen, i.e., how an organism will evolve, what genes will mutate etc, in a certain environment, is very difficult and really basically impossible. > What about the beatiful correspondence often found between the principle components of genetic variation and geographical position (isolation by distance)? Funny you mention this. There is a student I work with trying to observe this with metagenomics data with much less success than you might imagine.
saxonklaxon 10y ago
Which branch of science or philosophy did you apply to reach your non-squishy conclusion?
jhbadger 10y ago
On the other hand, those "squishy sciences" have nothing as squishy as string theory, which can't even be tested experimentally. In most sciences, theory papers without confirmatory experimental results to show that that it isn't mere fantasy are rejected.
- stult 10y ago
  There's nothing squishy about string theory. The line between currently untested hypotheses and those supported by reliable experimental results is quite clear in physics. You frequently see journalists representing the results of unreplicated garbage psychology experiments as scientific fact yet you never hear anyone claiming string theory is any such thing. We know how to test string theory but we lack the ability to generate sufficient energy to do so. We don't even know how to reliably test many of the theories generated by the social sciences. That's the difference between a robust science and a squishy one: effective methods for generating and testing hypotheses. String theory is part of the "generating" process. It makes falsifiable and (theoretically) testable predictions. There's no reason that experimental results are required for that process, so long as everyone is clear about the hypotheses not being experimentally supported yet. The separation between theoretical and experimental physics is particularly necessary because testing quantum physics hypotheses involves multi-billion dollar investments in particle colliders. Yet once that investment is made, the experiments are effective at testing the theories and the theories are effective at being tested by experiments. You can't say the same about the squishier end of the scientific spectrum.
  - jhbadger 10y ago
    The comment I was responding to was specifically calling out biology as "squishy". As a computational biologist myself, I have experience in getting my purely computational papers rejected before I learned that you have to collaborate with experimentalists to get a really good paper.
    - xaa 10y ago
      (Fellow CB here) I have had the same experience. Although I think this phenomenon is because of a heavily empirical bias in biology, not because the experimental data that is usually paired with comp bio models is actually all that useful in supporting the model. "Generate hypothesis with CB and present experimental data that is mostly irrelevant to it" seems to be a good recipe for getting Nature papers, actually.

analog31 10y ago

It's also harder to do things to plants and mice, much less humans, without knocking them so far out of balance that it ceases to be a meaningful experiment.

jfarlow 10y ago
That's a strong statement. I'd say it 'ceases to be trivially interpretable'. And I think this is part of where the 'the published paper said ___ so it must be true!' disparity between scientists and public becomes more apparent. In biology when you design a good experiment, run it, come up with a model that fits your experiment, no scientist would ever pretend that their articulated model was how things actually worked. It's close, it's reasonable, but many more publications would be needed to confirm it. A single publication just is not enough to decomplexify the entanglements in biology. Many other scientists will use that model as the basis for their newer experiment, and when their results do not comport, they alter, adjust, or if need be, discard the original model. The trouble with biology is it might take an entire 'Cell' paper (12 pages of dense publication - ie, many many grad-student-years of work) just to come up with the most simplistic model for what the biological experiment observed. That doesn't mean it wasn't meaningful - it was just much more complicated and less easily well-describable than physics and chemistry experiments. But very much like physics and chemistry, there is a definite trend towards a well-described and predictable system. Models actually get increasingly accurate over time. And this feature might be part of the border in defining a 'robust' science.
- xaa 10y ago
  > just to come up with the most simplistic model Yeap. Bioinformatician here. Not only are most published models overly simplistic -- which everyone acknowledges -- but I think our bigger problem is we don't even have a reasonable "meta-model" of biology. What I mean by that is, imagine experiments were instantaneous and free. How would we then incorporate the results into a mathematical/computational/predictive framework that describes biological reality in a way analogous to physics? AFAIK, we haven't the foggiest clue. Biology is pretty theory-light and empiricism-heavy, probably because we have good results with things like "I dunno what this mold is secreting, but it seems to be killing the bacteria!" So our experimental results are pretty precise (although arguably not "robust" between strains/conditions/etc), when people bother to use n>3, but the models and theory are anything but.
semi-extrinsic 10y ago
> knocking them so far out of balance that it ceases to be a meaningful experiment Things in physics can sometimes be knocked so far out of balance during an experiment it boggles the mind, while still rendering perfectly sensible observations. E.g., I once heard the LHC described as "trying to determine how a grand piano works by throwing lots of them one after one down a very long set of well-defined stairs equipped with lots of very sensitive microphones and force sensors". In other cases, nothing could be farther from the truth. Say you are measuring heat transfer coefficients in high-Re laminar flow through a tube. A single 100-micron step imperfection in the tube wall will render your results pretty much useless. The distinguishing feature of physics is perhaps that one can know to a very high degree of precision before constructing the experiment which parameters/uncertainties it is very sensitive to.

0x445442 10y ago

Agreed, from a Physicist's perspective, Darwin's Theory is extremely "squishy".

Luc 10y ago
Nonsense.
jon2k17 10y ago
Could you expand on that?
ealloc 10y ago
My impression is that physicists who say this usually don't know much about the theory and evidence for evolution. (I am trained in physics, I now do biophysics). What about the beautiful and often very precise linear relationship between radioactive dating of the fossil record, and genetic dating using the molecular clock? What about the beatiful correspondence often found between the principle components of genetic variation and geographical position (isolation by distance)? What about all the biochemical discoveries related to DNA function (including the existence of DNA itself), how mutations occur, about heritability? What about everything we've discovered about genome composition and how it changes over time? (duplicate genes, pseudogenes, transposons, hotspots of various kinds). Is a DNA sequence less precise than a spectral line?
- xaa 10y ago
  (Bioinformatics) I wonder if he means not that evolution is false/unfalsifiable/irreproducible, but that it is not really a very predictive theory. I agree there is a lot of evidence that it happened and continues to happen, but predicting how it will happen, i.e., how an organism will evolve, what genes will mutate etc, in a certain environment, is very difficult and really basically impossible. > What about the beatiful correspondence often found between the principle components of genetic variation and geographical position (isolation by distance)? Funny you mention this. There is a student I work with trying to observe this with metagenomics data with much less success than you might imagine.

saxonklaxon 10y ago

Which branch of science or philosophy did you apply to reach your non-squishy conclusion?

jhbadger 10y ago

On the other hand, those "squishy sciences" have nothing as squishy as string theory, which can't even be tested experimentally. In most sciences, theory papers without confirmatory experimental results to show that that it isn't mere fantasy are rejected.

stult 10y ago
There's nothing squishy about string theory. The line between currently untested hypotheses and those supported by reliable experimental results is quite clear in physics. You frequently see journalists representing the results of unreplicated garbage psychology experiments as scientific fact yet you never hear anyone claiming string theory is any such thing. We know how to test string theory but we lack the ability to generate sufficient energy to do so. We don't even know how to reliably test many of the theories generated by the social sciences. That's the difference between a robust science and a squishy one: effective methods for generating and testing hypotheses. String theory is part of the "generating" process. It makes falsifiable and (theoretically) testable predictions. There's no reason that experimental results are required for that process, so long as everyone is clear about the hypotheses not being experimentally supported yet. The separation between theoretical and experimental physics is particularly necessary because testing quantum physics hypotheses involves multi-billion dollar investments in particle colliders. Yet once that investment is made, the experiments are effective at testing the theories and the theories are effective at being tested by experiments. You can't say the same about the squishier end of the scientific spectrum.
- jhbadger 10y ago
  The comment I was responding to was specifically calling out biology as "squishy". As a computational biologist myself, I have experience in getting my purely computational papers rejected before I learned that you have to collaborate with experimentalists to get a really good paper.
  - xaa 10y ago
    (Fellow CB here) I have had the same experience. Although I think this phenomenon is because of a heavily empirical bias in biology, not because the experimental data that is usually paired with comp bio models is actually all that useful in supporting the model. "Generate hypothesis with CB and present experimental data that is mostly irrelevant to it" seems to be a good recipe for getting Nature papers, actually.