81–90 of 143 posts
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I'm confused, isn't the whole schtick around past events being related to future events the basis of causality?
What evidence do we have that causality will continue to “exist”?
You can't argue that causality is real because it's always worked; that is begging the question.
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People who believe that past experience is a good predictor of the future will make decent predictions as a result; people who believe that past experience has nothing to do with the future ("anti-inductivists") will make wrong predictions again and again. The inductivists will therefore outcompete the anti-inductivists. On the other hand, as a friend of mine pointed out, for the anti-inductivists that manage to exis…
> The inductivists will therefore outcompete the anti-inductivists. You have no deductive or a priori reason to know this, rhetoric about "epistemically traps" aside.
Now, if one were to try to construct a theoretical argument, I suspect it would go as follows: "If we assume the world could change in every aspect from moment to moment (e.g. pieces of matter could teleport anywhere in the universe, physical constants might change by the second, laws of physics might change over time or space, the very concepts of space and time might become invalid, ...), then the space of possible worlds is enormous and incomprehensible. If we don't have any rational way of assigning probabilities to any of the possible worlds, then this method of thinking doesn't have any implications for correct actions, because every action could be the best in some possible world; in that case, as long as you assign nonzero probability to the "laws of physics remain constant" universe most of us believe in, you may as well act as though it's the truth." If someone does claim to have a rational way of assigning probabilities to the possible worlds, then that would have to be addressed on its own terms, and any conclusion may be possible; but most such ways that people have proposed will tend to imply that "simple" possibilities are most likely, and "the laws of physics remain constant" will tend to rank highly among them.
Her frustration with the priorities of theoretical physics probably is justified, but in this case I disagree with @skdh. Her claim is that any solution for the BHIP cannot be falsified, and that strikes me as too pessimistic for two reasons. First, look at the results of pushing the theory harder with respect to spinning black holes. Many predictions of Kerr's theory have been observed, even if the ring singularity…
Ancient philosophers debated the existence of atoms for centuries; then Boltzmann took the theory up to second gear by discovering the implications on temperature and entropy, and then Einstein proved their existence beyond a shadow of a doubt through his work on Brownian motion.
It might take centuries of mathematical work to discover an artifact of quantum gravity that's observable within our macroscopic world, but the work must be done.
Not a physicist, but Hossenfelder didn't clarify well that, unlike previous proposed solutions, this one only relies on standard quantum mechanics and general relativity, not strings or LQG. Similar in spirit to Hawking's original approach, which she did mention. She seems to have a beef with extrapolating (even well-accepted) math, rather than doing experiments. But this kind of work clarifies where the theories cla…
So this new result is derived semiclassically, right? Which means it was derived using more or less the same assumptions Hawking used to derive Hawking radiation. So couldn't the same objection be made about the claim that black holes evaporate at all? After all, we also have no empirical data about that, and likely won't have such data for a long long time.
Earlier quoted context omitted.
I'm confused, isn't the whole schtick around past events being related to future events the basis of causality?
What evidence do we have that causality will continue to “exist”?
Earlier quoted context omitted.
> The inductivists will therefore outcompete the anti-inductivists. You have no deductive or a priori reason to know this, rhetoric about "epistemically traps" aside.
That's true. "Induction works in practice" is merely an empirical fact. But it is a fact. Our bodies embed it already: evolution has worked because the environment has changed slowly enough for advantageous mutations to remain advantageous for long enough to become ubiquitous in the species. But, again, the thesis "empirical evidence doesn't matter" is immune to empirical evidence. Now, if one were to try to construc…
I like the tenor of your second argument, it reminds me of Pascal's wager. That said, you're not really addressing the problem of induction. We have no reason why you'd assign a higher probability to the "law of physics remain constant" to the "laws of physics are flipped in the next second", outside of gut reasoning.
If we can use gut reasoning about induction, no reason we can when we assume that quarks are a real thing, or think about this solution to the BHIP.
Her frustration with the priorities of theoretical physics probably is justified, but in this case I disagree with @skdh. Her claim is that any solution for the BHIP cannot be falsified, and that strikes me as too pessimistic for two reasons. First, look at the results of pushing the theory harder with respect to spinning black holes. Many predictions of Kerr's theory have been observed, even if the ring singularity…
I suppose her reason to assume we can't observe this is that evaporation takes extremely long time. For example, a solar mass black hole will take about 10^64 years to evaporate [1] (this is approximately 7 * 10^54 times the age of the universe). Note that astronomical black holes are heavier than the Sun, so take even longer to evaporate.
I suppose the micro black holes [2] might offer a glimmer of hope, but these objects are entirely hypothetical.
[1] https://en.wikipedia.org/wiki/Hawking_radiation#Black_hole_e... [2] https://en.wikipedia.org/wiki/Micro_black_hole
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> It's a theory that is almost uniquely derived from a pre-existing set of assumptions that do have a large body of empirical support. What additional assumptions (on top of the ones Hawking made) does the new calculation use that don't have a large body of empirical support?
The most plausible solutions can be read on Wikipedia along with the assumptions they either make, or violate: https://en.wikipedia.org/wiki/Black_hole_information_paradox...
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> The inductivists will therefore outcompete the anti-inductivists. You have no deductive or a priori reason to know this, rhetoric about "epistemically traps" aside.
So is this survivorship bias or something else? I don't understand your point. I have a white wall in front of me. If I take a brush and red paint and paint a big red circle on the wall, are you saying that the big red circle "just happens to be there" with no relationship to the brush, red paint and my actions?
All of our data about gravity is equally consistent with the theory “If I drop an apple it will fall only if it is before December 2020” as it is with our theory that the law of gravity will continue to exist in the future as it does today.