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Occam's razor is a heuristic used in the investigative process, not a principle. While it's fair to point out that a theory makes everything more complicated an

Occam's razor is a heuristic used in the investigative process, not a principle. While it's fair to point out that a theory makes everything more complicated and thus might make it less likely to be sound, it's not fair to push back on the first bit of research into a theory because they haven't had the time to fully develop it. Indeed, a scientific revolution generally starts by treating as false an assumption previously held as true. Not to say that this is a revolution, but if you push back too hard it won't be, whether it's true or not.

garmaine 8y ago
Also that point seemed odd. Isn't unification of two previously separate phenomenon (dark matter and dark energy) simpler in Occam terms? It's using one thing to explain two, even if the actual mathematics are more complex to state. Also there's other troubling cosmological issues that this would appear to address, such as Hubble's constant having slight variation outside of measurement tolerance, which slightly differing fluid densities would explain (vs the current assumption of unknown sources of error). Sabine's point, if it stands up, is that the author used a different equation of motion in their simulation than they write up in the paper. If true that's sloppy and bad, but it's not a point against the actual theory underlying the simulation, no?
- ajkjk 8y ago
  Whether it is simpler depends on the details of the unification. Two comparatively simple theories are not made simpler with a very complex unification.
  - vanderZwan 8y ago
    One could also think of it in terms of the the amount of "magic" required to make the simplification work.
  - garmaine 8y ago
    The electroweak force is most certainly not easier to describe than electromagnetism and the weak force separately. But we still talk about electroweak interaction as being a simpler theory than two separate fundamental forces, because it reduces the number of things that are needed to describe the universe, even with added computational difficulty.
- jcranberry 8y ago
  As far as I can tell Occam terms seem to differ depending on the convenience of whoever happens to be wielding Occam's razor.
jetrink 8y ago
As I read that paragraph, I thought to myself that the author should read Sabine Hossenfelder's recent book Lost in Math: How Beauty Leads Physics Astray. In that book, Sabine argues quite convincingly that our aesthetic judgements of new theories can mislead us. She says of simplicity, > This dream still drives research today. But we do not know whether more fundamental theories necessarily have to be simpler. The assumption that a more fundamental theory should also be simpler—at least perceptually simpler—is a hope and not something that we actually have reason to expect.
- throwawaymath 8y ago
  > As I read that paragraph, I thought to myself that the author should read Sabine Hossenfelder's recent book Lost in Math: How Beauty Leads Physics Astray. The author is Sabine Hossenfelder :)
  - jetrink 8y ago
    I realized when I reached the bottom of the post. It is odd to me to see her saying that the new theory is disqualified for not being as simple as alternatives after reading her book.
    - rwilson4 8y ago
      It's not disqualified for not being simple, it's disqualified for not making testable predictions. Given two theories, neither of which make testable predictions, the simpler one (and the one that has been studied more thoroughly) is the more reliable. Otherwise, why not just say that the missing mass is unicorns? And the energy driving the accelerated expansion of the universe is the energy of their love? There's no shortage of radical explanations for dark mass/energy. The scientific community takes them seriously to the extent that they are compatible with past observations and make testable hypotheses that distinguish them from other theories.
      - poopchute 8y ago
        The author of the negative mass theory said that it will be testable via the cubic kilometer ice array in Antarctica when it comes online (though I'm not sure how). He mentions it in his chain of 17 tweets that summarize the theory .
rytill 8y ago
It's not totally a heuristic, though it's intractable to use it the real way. Which theory has a shorter program that generates it?
sgt101 8y ago
History : Dun Scotus (really) probably invented Ockham's razor - William was his student and used it to avoid the thing that all medieval philosophers needed to avoid, namely being tied up and put on a bonfire. Why did Dun invent it (probably)… well here's the thing, Christianity has a God with three faces, son, father and holy ghost thing. Why? The answer is - don't multiply entities beyond necessity, so God has the number of faces necessary to do the job, no more, no less. I'm wittering on because this is where that heuristic came from, literally it's angels on pins stuff. So don't invest in it, I'd bet a bit that if we got Dun and Bill together with a few pints of mead they'd laugh themselves silly to here that 21st Century physics pins any weight onto their measure. The Greeks wouldn't have, the Chinese didn't, why do we?
- c1ccccc1 8y ago
  I mean, we still call it Occam's razor, but I don't think that it's really even the same principle by this point, it just shares the same name. In science today, we don't really care about the number of entities. We don't reject the idea that the stars are suns like our own just because that would imply that the number of atoms in the universe is drastically larger than the number of atoms in the solar system. Instead of hypotheses with the least number of entities, we favour hypotheses with the smallest Kolmogorov complexity. [1] As a slogan for the modern version, I like the phrasing by John Von-Neumann: "With four parameters I can fit an elephant, and with five I can make him wiggle his trunk." [2] [1] https://en.wikipedia.org/wiki/Kolmogorov_complexity https://en.wikipedia.org/wiki/Kolmogorov_complexity [2] https://www.johndcook.com/blog/2011/06/21/how-to-fit-an-elephant/ https://www.johndcook.com/blog/2011/06/21/how-to-fit-an-elep...
  - comex 8y ago
    Nitpick: The historical problem with stars being suns wasn't (just) the universe being larger than the solar system, but that the telescopic observations available at the time seemed to imply that every other visible star would have to be much larger than the Sun, in fact larger than the orbit of Saturn. This was because early astronomers didn't understand optical diffraction and thought the Airy disks visible around stars were the stars themselves, making their angular radius in Earth's sky seem vastly larger than the reality. [1] Both characterization of the Airy disk and observation of stellar parallax didn't occur until the 19th century, by which point religious objections wouldn't have had the same status as in Galileo's day anyway (for example, Darwin's work was published only a few decades later). Source: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.612.5617&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.612...

garmaine 8y ago

Also that point seemed odd. Isn't unification of two previously separate phenomenon (dark matter and dark energy) simpler in Occam terms? It's using one thing to explain two, even if the actual mathematics are more complex to state. Also there's other troubling cosmological issues that this would appear to address, such as Hubble's constant having slight variation outside of measurement tolerance, which slightly differing fluid densities would explain (vs the current assumption of unknown sources of error). Sabine's point, if it stands up, is that the author used a different equation of motion in their simulation than they write up in the paper. If true that's sloppy and bad, but it's not a point against the actual theory underlying the simulation, no?

ajkjk 8y ago
Whether it is simpler depends on the details of the unification. Two comparatively simple theories are not made simpler with a very complex unification.
- vanderZwan 8y ago
  One could also think of it in terms of the the amount of "magic" required to make the simplification work.
- garmaine 8y ago
  The electroweak force is most certainly not easier to describe than electromagnetism and the weak force separately. But we still talk about electroweak interaction as being a simpler theory than two separate fundamental forces, because it reduces the number of things that are needed to describe the universe, even with added computational difficulty.
jcranberry 8y ago
As far as I can tell Occam terms seem to differ depending on the convenience of whoever happens to be wielding Occam's razor.

jetrink 8y ago

As I read that paragraph, I thought to myself that the author should read Sabine Hossenfelder's recent book Lost in Math: How Beauty Leads Physics Astray. In that book, Sabine argues quite convincingly that our aesthetic judgements of new theories can mislead us. She says of simplicity, > This dream still drives research today. But we do not know whether more fundamental theories necessarily have to be simpler. The assumption that a more fundamental theory should also be simpler—at least perceptually simpler—is a hope and not something that we actually have reason to expect.

throwawaymath 8y ago
> As I read that paragraph, I thought to myself that the author should read Sabine Hossenfelder's recent book Lost in Math: How Beauty Leads Physics Astray. The author is Sabine Hossenfelder :)
- jetrink 8y ago
  I realized when I reached the bottom of the post. It is odd to me to see her saying that the new theory is disqualified for not being as simple as alternatives after reading her book.
  - rwilson4 8y ago
    It's not disqualified for not being simple, it's disqualified for not making testable predictions. Given two theories, neither of which make testable predictions, the simpler one (and the one that has been studied more thoroughly) is the more reliable. Otherwise, why not just say that the missing mass is unicorns? And the energy driving the accelerated expansion of the universe is the energy of their love? There's no shortage of radical explanations for dark mass/energy. The scientific community takes them seriously to the extent that they are compatible with past observations and make testable hypotheses that distinguish them from other theories.
    - poopchute 8y ago
      The author of the negative mass theory said that it will be testable via the cubic kilometer ice array in Antarctica when it comes online (though I'm not sure how). He mentions it in his chain of 17 tweets that summarize the theory .

rytill 8y ago

It's not totally a heuristic, though it's intractable to use it the real way. Which theory has a shorter program that generates it?

sgt101 8y ago

History : Dun Scotus (really) probably invented Ockham's razor - William was his student and used it to avoid the thing that all medieval philosophers needed to avoid, namely being tied up and put on a bonfire. Why did Dun invent it (probably)… well here's the thing, Christianity has a God with three faces, son, father and holy ghost thing. Why? The answer is - don't multiply entities beyond necessity, so God has the number of faces necessary to do the job, no more, no less. I'm wittering on because this is where that heuristic came from, literally it's angels on pins stuff. So don't invest in it, I'd bet a bit that if we got Dun and Bill together with a few pints of mead they'd laugh themselves silly to here that 21st Century physics pins any weight onto their measure. The Greeks wouldn't have, the Chinese didn't, why do we?

c1ccccc1 8y ago
I mean, we still call it Occam's razor, but I don't think that it's really even the same principle by this point, it just shares the same name. In science today, we don't really care about the number of entities. We don't reject the idea that the stars are suns like our own just because that would imply that the number of atoms in the universe is drastically larger than the number of atoms in the solar system. Instead of hypotheses with the least number of entities, we favour hypotheses with the smallest Kolmogorov complexity. [1] As a slogan for the modern version, I like the phrasing by John Von-Neumann: "With four parameters I can fit an elephant, and with five I can make him wiggle his trunk." [2] [1] https://en.wikipedia.org/wiki/Kolmogorov_complexity https://en.wikipedia.org/wiki/Kolmogorov_complexity [2] https://www.johndcook.com/blog/2011/06/21/how-to-fit-an-elephant/ https://www.johndcook.com/blog/2011/06/21/how-to-fit-an-elep...
- comex 8y ago
  Nitpick: The historical problem with stars being suns wasn't (just) the universe being larger than the solar system, but that the telescopic observations available at the time seemed to imply that every other visible star would have to be much larger than the Sun, in fact larger than the orbit of Saturn. This was because early astronomers didn't understand optical diffraction and thought the Airy disks visible around stars were the stars themselves, making their angular radius in Earth's sky seem vastly larger than the reality. [1] Both characterization of the Airy disk and observation of stellar parallax didn't occur until the 19th century, by which point religious objections wouldn't have had the same status as in Galileo's day anyway (for example, Darwin's work was published only a few decades later). Source: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.612.5617&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.612...