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Let me push back on the notion that there are alternative explanations besides increased concentration of atmospheric CO2 and other greenhouse gases for the current rapid changes in climate. It's one thing to say that we should distrust the complicated models that try to simulate the entire Earth in sufficient detail to predict exactly what the temperature change will be and what the impacts will be in each region. That stuff is genuinely hard to predict and I won't be surprised if the models get lots of things wrong. But the basic mechanism by which higher CO2 concentrations enable to atmosphere to retain heat better is dead simple. Heat is lost from the ground and atmosphere by low frequency photons that radiate away into space. Many of the photons, especially those emitted from the ground and lower parts of the atmosphere will be scattered by gas molecules in the atmosphere, and CO2 is one of the gases that is particularly good at this. Scattering means that the photon's direction changes randomly, which means that there's a good chance that it will be redirected to be heading back down towards the ground, rather than out into space. So an increased number of scattering events improve heat retention. Adding more CO2 to the atmosphere increases the number of of scattering events and thus results in less heat being lost to space, which results in a higher average* temperature for the Earth. We can debate what the exact consequences of all this will be, but saying it isn't a result of humanity burning large quantities of fossil fuels is to me tantamount to an admission that you don't understand physics.

*(Technically, since thermal radiation goes as T^4 times emissivity and some other stuff, what I really mean is a higher value of T^4 averaged across the surface area of the Earth and weighted by emissivity. And even this is an oversimplification, since not only can heat be lost from the ground, but also the atmosphere iteself. But the basic picture of "planet gets warmer" is still correct.)

Thanks for replying with details. The difference for liquid water is small, but for ice it looks like it's actually about 7%, which could be significant. Looks like what's going on is that the constants used are for different temperatures. The original constant was for ice at 0C, while the new constant is for ice at -15C. I'm guessing this is probably based on the thought that more ice on the planet is near -15C than is near 0C. Ideally for the best accuracy you'd compute the heat capacity using interpolation and a lookup table, but I can see how it would be a lot harder to enforce energy conservation that way. It would be interesting to see a sensitivity analysis on how these kinds of decisions affect the outcome of the simulation.

Is it possible for you to link any of the climate models where you've observed this and point out some of the inaccuracies? (Or to link to an existing blog post or comment that does so?)

What do you make of the argument that if you give the police your phone, you are in fact fully cooperating by giving them all data on that phone, and it's not your fault if they don't have sufficient information to interpret that data? To take a different example, if Bob is writing things down in a notebook, but using some kind of secret language or code that he made up, it seems pretty clear that while the police have the right to seize the notebook, Bob correspondingly has the right to refuse to translate for law enforcement. Similarly, maybe Bob's code is a little more complicated, and requires using a calculator to compute what each codeword should be. It still seems like Bob has a right not to answer. Is using a computer rather than a calculator to do the encryption the final straw?

Sorry for what's probably a stupid question: I see there's 2 featured courses on the home page, how do I view other courses? I don't see a search bar anywhere.

I'm not the person you replied to, but just wanted to add something to help answer Q2. Communicating information to a large fraction of the populace is generally pretty hard because there are so many memes competing for attention, and true information doesn't necessarily spread faster than false information. Even so, it's pretty much common knowledge that the Iraq war was based on a falsehood, so communication does work well enough at least some of the time. Okay, so suppose we now collectively know that most politicians are liars and will have no issue with lying when it's convenient for them and they expect to get away with it. I think it's very common to find people who think this in western countries, actually.

Now how do we vote in such a way as to make sure we elect non-liars? Being a liar is not always visible, but maybe we can determine it by looking at whether the candidate lied while holding previous offices, and whether or not they get caught in any lies while on the campaign trail. We may also be able to make some judgment of a person's honesty based on how they make arguments, i.e. how they use statistics, and how often they omit relevant information that would look bad for them.

So suppose that everyone could perfectly identify who was a liar and who was honest. Would the electorate then vote only for honest politicians? Nope. A voter finds other things valuable in a politician besides just honesty, for example agreement on policy issues, or allocating tax money in a way that benefits the voter. Even if the candidate for party A is found out to be a no-good stinking liar, that still might not be enough to induce a party A voter to vote for the party B candidate instead. After all, party B is terrible. And there can be no party C that adopts the policy stances of party A but is staffed by honest politicians. Because of vote splitting in first-past-the-post electoral systems, two parties tend to dominate with outsiders having no chance of getting elected, even if the electorate prefers the outsiders. This is why we'd ideally want to use a more sane electoral system like score voting.

I like this explanation and the one in the parent comment quite a bit. Rather than a grand thesis about internet / social media [0] / polarization that one's likely to see in a think-piece, it's the little things about how we've chosen to structure our society. These things that seem like trivial inconveniences [1], like just making some new friends when yours have moved away, or if you live the suburbs just taking that 20 minute drive whenever you want to see someone, end up having a disproportionate impact on our behaviour. After all, we evolved in an environment where one was pretty much automatically embedded in a community, with very little effort required to socialize other than following the social norms of the tribe.

One other thing I'd also point to is network effects. If lots of people are all finding it easier to be online all the time rather than be social, then for any given person, that results in a reduced number of potential friends.

[0] I would actually put some blame on social media for being a poor substitute for socialization, but just good enough that it makes people less likely to dig themselves out of being isolated. But blaming the internet in general, including things like blogs makes as little sense as blaming books.

[1] https://www.lesswrong.com/posts/reitXJgJXFzKpdKyd/beware-tri...

I agree that's it's possible to create objective collapse theories that are arbitrarily difficult to falsify, but the difference between objective collapse and regular old decoherence due to interaction with the environment has experimentally measurable implications. In particular, if you expect a certain probability of objective collapse in a certain period of time, then do an experiment with a coherence time longer than that, while keeping your system carefully isolated from interaction with the environment. Then if the wavefunction collapses anyway, that would prove objective collapse and disprove many worlds.

Many worlds is absolutely testable, since if we observe collapse in even a single one of these experiments then that completely falsifies many worlds. If one of these experiments discussed in the article had actually observed a collapse, then I have no doubt we'd be seeing headlines like "many worlds theory disproven", and Nobel prizes for the physicists involved. It would be the biggest discovery in physics for decades.

Wait, I'm pretty sure that if these measurements had shown a collapse, that would have to be taken as disproving many worlds. You can't very well have many worlds when your wavefunction is physically collapsing all the time before those worlds can diverge. So it is actually kind of testable, since a test was just performed that could have ruled it out. Maybe you're saying that it's untestable relative to unmeasurable collapses of the wavefunction. But if those collapses are contrived to be unmeasurable, doesn't that make them kind of, well, pointless?

It's not just a relabelling. In collapse theories, the wavefunction stops obeying the Schrodinger equation for a moment and discontinuously jumps to a new state. The times when it performs a discontinuous jump are called "measurements", though this doesn't necessarily mean there's a scientist sitting there with a ruler, it just means that the system has interacted with its environment sufficiently. In the many worlds theory on the other hand, the wavefunction continues to obey the Schrodinger equation for all time, and the natural result of this is that the wavefunction becomes very complicated and entangled, so that the motion of atoms here on Earth is very entangled with photons heading away from us at the speed of light out into deep space, along with pretty much everything else. But there's no mention of "separation" or "worlds" in the basic description of the theory; the one sentence description of many worlds is "the wavefunction obeys the Schrodinger equation all the time with no exceptions".

Where the worlds come in is that it's impossible to do calculations on the wavefunction of the entire universe, so we need to come up with a way of dividing it up into manageable pieces. Not because the theory requires that it be divided into pieces, but because otherwise we couldn't handle the math. The worlds are one of the ways we do that: We break the wavefunction of the universe into approximately perpendicular components that don't interfere with each other very much and don't have too much entanglement making them hard to understand, and we call those worlds. We can further simplify things by just looking at a subsystem of the universe rather than the entire universe, which involves taking a partial trace (this tends to introduce randomness). As time goes on and entropy increases, the entanglement and complexity even within a "world" will continue to increase and at a certain point we may notice, "hey, this component is really complicated now, and it can itself be divided into subcomponents that are approximately orthogonal and don't really interact with each other much, I can simplify my calculations by treating those as separate worlds now". This is what we mean when we say that worlds tend to split apart, but since the worlds are only approximately orthogonal and independent, when you define splitting is really a matter of how much error you're willing to allow in your calculations. (Also, the process of splitting is driven by increasing entropy, so when (if?) the universe reaches a point of total heat death and entropy stops increasing, this will also imply that the worlds have stopped splitting.)

So I'm not sure what you mean by "strong and exceptional". It's just math, and can be compared with experiment just like any other piece of physics. Take the experiments done in the original article. If any kind of collapse had been observed, then that would have straight-up falsified the many worlds theory. Many worlds says that physical systems can become entangled with their environments, but their wavefunctions can never just collapse, and these two cases are distinguishable in a careful experiment. Since collapse wasn't observed when these tests were done, that provides a little bit of evidence in favour of many worlds.

Falsifiability is a little more complicated for collapse theories. People don't agree on the exact definition of a "measurement", and what level of interaction with the environment is required to trigger a collapse, but in order to have a falsifiable theory, it's important that we have a precise, mathematical definition of when a collapse should happen (this definition does not have to be deterministic, it could just give us a probability distribution). So various people have put forward different definitions, and it sounds like these experiments have ruled out a bunch of them, but obviously they haven't ruled out every collapse theory put forwards by every physicist ever. It's a bit like when the LCH failed to find any supersymmetry particles, and some physicists were like, "okay, but in my version of supersymmetry, the particles are heavier than the energies reachable by the LHC so of course we wouldn't expect to have seen them".

Is it just me, or is this article really spammy and low-quality? It's full of buzzwords like "advanced knowledge in cutting-edge Machine Learning solutions" and "completely new paradigms for enhanced creativity". Meanwhile it has no technical details about what their model actually does or how it works. It basically reads like an ad.

(Also the model still needs help from human experts to fix its formulas, so the "better than professional humans" title that someone choose when posting to HN is a lie.)

Sounds like something we could check empirically. Some cosmic rays are protons from outside of the solar system. We could capture those and compare them with local protons to see if they're actually the same kind of particle. (We can check if two particles are the same kind or not by seeing what happens if we try to put them in the same place. If they're both protons, they should refuse to be put into the same state due to the Pauli exclusion principle.) As far as I know the experiment hasn't actually been done, though.

Is that really true about Feynman? I thought he wrote in "Surely You're Joking" that he didn't take psychoactive drugs because he loved thinking and he "didn't want to mess up the machine".

Reminds me of this story: https://slatestarcodex.com/2017/11/09/ars-longa-vita-brevis/

Fortunately, it should be possible to determine which is true, since there is a very large control group in the form of people who have opted not to be vaccinated.

You got the direction backwards. Increase in entropy means that the farther back you go in time, the less information the universe has in it in some sense. The initial state of the universe would therefore be very simple, having low entropy. If the state were simple enough, then in principle, we could figure it out in exact detail. The thing that thermodynamics says is unknowable is the distant future of the universe. We can predict that it will be dark and cold and empty and sparsely filled with ever-more red-shifted radiation, but it's impossible, even in principle, to know the details of exactly where each individual particle in going to end up.

Your position/speed/acceleration analogy is misleading from a physics perspective. The amount of GHG in the atmosphere determines an equilibrium point. More GHG corresponds to a hotter equilibrium. There's some delay in moving to the new equilibrium, so even if we stopped all emissions, the world would keep getting hotter for a little while before settling at the new equilibrium. But removing GHG from the atmosphere does lower the equilibrium temperature, even if we don't get it all the way back to pre-industrial levels.

> Parthenogenetic offspring in species that use either the XY or the X0 sex-determination system have two X chromosomes and are female.

From this we can infer that Jesus had two X chromosomes, and was therefore a trans man.

And in both cases those making the claims have somehow managed to ignore existing biological counterexamples.

I haven't checked the geological suitability, but assuming you're right about that, putting the waste in those places seems perfectly fine to me.

That seems super unlikely to be a problem. For long term storage, I'd expect that we'll dig a deep shaft, or use an existing abandoned mine, and then seal it back up. Any group of humans who are willing and able to make a hole through several meters of concrete in order to get at the stuff will almost certainly also have the technological sophistication to know what radiation is, and that radioactive isotopes are dangerous.

Also, if you do decide to leave a message anyway, you'll just have to make it interpretable to a human, not to any possible "creature". 10 000 years is nothing on evolutionary time scales, so it will still just be us humans around, (or nobody at all, if we happen to go extinct first).

200,000 years is not much on geological timescales. Here's one example of a place with very stable geology: https://en.wikipedia.org/wiki/Canadian_Shield

The other main thing to remember when burying nuclear waste is that it's important to keep it away from aquifers and generally any flow of water under the ground. Obviously you'd probably want to seal it in waterproof containers anyway, but it's better to not have to rely on the container staying intact over long spans of time.

1% per what? 1% per GWh? Coal power kills a huge number of people through air pollution, and that's during regular operation. So for me personally, coal power is much more scary than nuclear power.

If a box of gas (or a bar of iron, or a meteor shower) is capable to doing arbitrary computations, then go ahead and use a box of gas to factor some big numbers. The gas has 10^23 atoms that are all colliding with other atoms extremely often, so the amount of computing power available should be vastly greater than our current capabilities and it should be possible to factor correspondingly larger numbers.

Of course, any real-life attempts to use a box of gas to do such computations will fail. What's missing is the enormously complicated mapping between the starting and ending states of the gas, and the inputs and outputs of the factoring problem. This mapping is not just a matter of mapping bits in a local way into positions of gas atoms, but requires incredibly non-local dependencies between components. Interpreting the position of just a single atom in the gas requires knowing what pretty much all the other atoms in the gas are doing as well. If you had to actually compute that mapping, it would be about as difficult as both both simulating the gas's dynamics, and factoring the number.

At this point, a reasonable person would probably start to suspect that the actual factoring calculation is being shoved into the interpretation of the inputs/outputs of the system, and that the box of gas itself is not doing any calculations at all. Indeed, suppose that rather than letting the gas sit for a time t equalling perhaps a few seconds in order to do its computation, we instead let t=0. In this case, that atoms don't move at all during the "computation", but by clever mapping of inputs and outputs, we can still interpret this as "factorizing the number". Clearly the actual computation is happening in the "mappings" not in the gas.

Yes, self replicating machines would probably be required. But self replicators are definitely physically possible.

This is your friendly physics reminder that perpetual motion machines have nothing to do with this. It's hard to turn the whole planet into paperclips because paperclips are mostly made of iron, while the planet contains many other elements. Of course, with a high enough level of technology, it might be possible to fuse together the non-iron elements, so that you would end up with just a bunch of iron nuclei. This would even be energetically favourable, since iron is so stable. Then you just have to solve the issue that the paperclips in the center of the planet would be under huge pressure and would be crushed.

There's two things that can have symmetry here: The laws of physics themselves, and the system under investigation. The symmetries of the laws of physics don't get broken, but those of the system do. Compare a crystal to a gas: In a gas, the atoms are all bouncing around pretty randomly, so at any given point in space, there's roughly the same chance of finding an atom. Shift the gas to the left by distance x, and the local probability distribution of atom positions looks pretty much the same. In a crystal on the other hand, the atoms are still moving around and vibrating (so there's still some uncertainty in the positions of the atoms), but they tend to stay pretty close to their proper position in the crystal lattice. So the atoms are more likely to be in positions that line up with the rest of the crystal lattice than anywhere else. This breaks the symmetry. Shift by distance x and the peaks of that probability distribution no longer line up. The exception to this is if x is a multiple of the spacing of atoms in the crystal. Then you're shifting the peaks by exactly the right amount that they line up again when you're done. So a crystal doesn't completely break the symmetry of space, but it reduces it from a continuous symmetry (you can translate by any amount in any direction) to a much weaker discrete symmetry (only certain translations of space will preserve the symmetry).

A time crystal is similar to an ordinary crystal except that instead of reducing symmetry of translations in space from a continuous symmetry to a discrete symmetry, it reduces symmetry of translations in time from a continuous symmetry to a discrete symmetry.

EDIT: It's a little ironic that if you ask most people, they would say that a crystal is more symmetric that a gas, since a gas will look completely random and asymmetric if you take a snapshot of the positions of all the atoms at a single time. But since physicists care about the probability distribution of atom positions, they say that the gas is more symmetric than the crystal.

The phrase "AGI owner" implies a person who can issue instructions and have the AGI do their bidding. Most likely there will never be any AGI owners, since no one knows how to program an AGI to follow instructions even given infinite computing power. It's not clear how connectionism / using gradient descent helps: No one knows how to write down a loss function for "following instructions" either. Until we find a solution for this, the first AI to not to be "obviously erroneously evil" won't be good. It will just be the first one that figured out that it should hide the fact that it's evil so the humans won't shut it off.

We humans have gotten too used to winning all the time against animals because of our intelligence. But when the other species is intelligent too, there's no guarantee that we win. We could easily be outcompeted and driven to extinction, as happens frequently in nature. We'd be Kasparov playing against Deep Blue: Fighting our hardest to survive, yet unable to think of a move that doesn't lead to checkmate.

As the "end of sarcasm" marker, it means both:

"{sarcasm here} /s {seriousness here}"