John Michell: Country Parson Described Black Holes in 1783 (2000)
amnh.org
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Great show if you can find it. Another show, Connections, is much more popular, and traces the family tree of various inventions. Again, highly recommended!
Hard to believe it's a quarter of a century since it finished.
I miss all those relatively unflashy science programmes. They all have to be a bit over the top and made into rather showy but shallow “event” TV, probably featuring Brian Cox on a mountain or in a desert for some reason.
Hart-Davis has afaik been “cancelled” for some years.
* Newton and Leibniz with calculus
* Darwin and Wallace with evolution
* all those shared Nobel Prizes by independent scientists (eg: Feynman and Tomonaga/Schwinger with quantum electrodynamics, et al)
Presumably because knowledge converges and the field in question becomes ripe for discovery.
Take neural nets. FLOPS/$ crosses some magic number so that universities can afford the hardware, and bam; AI everywhere. No obvious theoretical breakthroughs since the 70s, but suddenly the field gets intense due to economics.
It's odd how blatantly simple stuff can be so difficult for even experts to see sometimes.
1) Schmidhuber does NOT claim to have invented it. He even provides lots of really old references. You know it's old when he didn't invent it, at least in his own mind.
2) even with his generous attributions, "the first application of backpropagation to neural networks" is from 1980.
3) "LeCun et al. (1989) applied backpropagation to Fukushima’s convolutional architecture (1979)".
In other words, the chain rule is really old but figuring out how to use that to adjust weights in neural nets was surprisingly unobvious. It was even more unobvious that that was a good way of adjusting weights.
These results would have all started to happen at about the time the cost of computation was within reach of the researcher's budgets. The "theoretical" breakthroughs are of the form "we can implement this technique from the 60s and get good results". Which is impressive, but it does not represent breakthroughs of knowledge as much as incremental improvements in hardware crossing key thresholds. The breakthrough is detecting that hardware can make something work now.
It most certainly would. Not in the 50's, of course, but in the 60's and 70's.
http://www.roylongbottom.org.uk/whetstone.htm
Look at the MFLOPS columns.
It seems to me that we had to wait until decent memory sizes and decent fp performance was a lot cheaper and therefore much more accessible => much easier to do experiments without having to justify them to higher-ups => somebody figured out 1) how to do backpropagation on neural nets and 2) that it was useful.
In other words, it wasn't obvious at all. It required experimentation.
It would have been practically useful from the 60's (for small neural nets and high-value problems) and 70's (not so small neural nets or lower-value problems) if somebody had figured out how to do it and that it was a useful thing to do.
Evolution is more debatable, it seems that Darwin's voyages of discovery were certainly an important part of his thinking. Still, it happened ~200 years after European ocean expeditions really started taking off, so doesn't seem like it was cutting edge experimentation.
The evolution of ideas seems like a much more plausible explanation.
Leibniz I'm not sure about, but given the timing? There was definitely a lot of interest in basic physics at the time and I bet that was related to his interests, somehow. It isn't a hard set of coincidences to imagine. That was all being fueled by improvements in measuring technology.
Evolution of ideas is plausible, but it suggests a remarkably homogeneous intellectual environment in a time where communication was expensive. Economic forces are a lot more likely to me, they scale. What we see in maths is usually one genius can discover a huge amount of stuff very quickly, they don't need to wait for other people to have ideas for them. They just need a little push in what to direct their attention to.
> Evolution of ideas is plausible, but it suggests a remarkably homogeneous intellectual environment in a time where communication was expensive.
Science doesn't often advance alone, it requires communication between scientists. And that same communication spreads ideas among those scientists, until they build a common understanding.
It is impossible to do physics by thought experiments. There are an infinite number of logically consistent mathematical models of universes out there, only a small subset of them match up reasonably well to the one we exist in. Science requires experiment. It doesn't have to be the same person doing the experimenter and interpreting the results, true enough, but the interpreter is still bottlenecked by data collection.
> Science doesn't often advance alone, it requires communication between scientists
No it doesn't. The whole point of this thread is that science often advances in parallel with no communication between scientists. Once the raw data has been collected - which is an economic issue - or conditions arise where a new problem needs to be solved - also economics - then it is a relatively short matter of time until someone comes up with a compelling theory. One very bright scientist can often exhaust a big chunk of what can be deduced from the currently collected data. And the implication of this is every time there is an economic advance in the cost of data collection there will be a big boom in scientific understanding.
People rediscover calculus to this day, every so often we all get a laugh because some very bright doctor figures out he can sum rectangles under a curve. The only limiting factor is whether people realise that they need to describe curves, areas and tangents precisely.
Thought experiments are an important tool used by many brilliant physicists when it is not possible to carry an actual experiment yet. Their usefulness is in the opposite of what you say: sure, they can't prove a teory correct, but they can point out potential problems by finding contradictions. As an example, here you can find a famous and very important thought experiment in the field of thermodynamics: https://en.m.wikipedia.org/wiki/Maxwell%27s_demon
Tell that to Einstein.
I can only suppose that you are taking 'communication' to mean only direct communication via face-to face conversation or the exchange of letters, but communication is a transitive operation, and, in fact, your thesis is tacitly predicated on this leading to the dissemination of knowledge. The more I learn about the actual history of science (as opposed to 'scientific genius' hagiography) the clearer this becomes.
If you are looking for an economic perspective on this, the emergence of the infrastructure of academic publication would be a good place to start.
Strongly disagree. The mathematical universes are heavily ordered by their simplicity and logical consistency and you can sort through them with thought alone.
Also, anyway, the act of 'doing physics' includes a lot more than the somewhat small category of 'testing hypotheses with experiment'. It's like 95% model building and 5% experiment.
Sure, but for the vast majority of physical theories before electrodynamics, our senses plus a few ancient instruments (meter sticks, hourglass, scales) were plenty enough. Galileo's relativity principle and his observation that all objects fall at the same rate in a vacuum were based on thought experiments and physical intuition, not actual experiment (apparently, he did try later to actually perform the experiment, but I think it didn't really work).
> The whole point of this thread is that science often advances in parallel with no communication between scientists. Once the raw data has been collected - which is an economic issue - or conditions arise where a new problem needs to be solved - also economics - then it is a relatively short matter of time until someone comes up with a compelling theory.
Sure, people can discover things in isolation. But science only advances when others learn of those things and can build upon them. Neither Newton nor Galileo nor the person in the article invented all of their theories from first principles - they were building on lots of thought and ideas that they had learned from other scientists.
> People rediscover calculus to this day, every so often we all get a laugh because some very bright doctor figures out he can sum rectangles under a curve.
Actually, calculating surface areas in this way is very very old - according to this Science article [0], it was already in use around 50 BCE. So it's not actually surprising that it has been rediscovered independently. I don't think much of Newton's work has been, apart from Leibniz (though that might also be because it's been so widely disseminated afterwards).
[0] https://www.science.org/doi/full/10.1126/science.aad8085
Microscopes were invented in the 1600s and cell biology as a discipline began soon after. But the dynamics of speciation were perhaps too grand to have been noted in the minutiae of slides.
And it would not be for almost another century after Darwin till we understood that the mechanics of evolution were driven by random mutations of DNA.
You can pretend the world is filled with tiny creatures all day long, but until you can see them with a microscope, it’s just an imaginative idea, not science.
Then the money dried up, as agriculture changed.
What was specific to the Anglican church in England at the time was that because of the control of the church by the state and the aristocracy it was possible for people with the right connections to be just handed the job with little requirement to do it. IIRC they could even pay curate to do the actual work.
So the English church had a rather unique arrangement where each parish had a source of funds independent of central government or church bureaucracy. That was the attraction of the job for intellectuals. As long as you kept your head down and didn't screw up big time, you were left alone.
Yes Parsons had a class-based sinecure and several of them made huge contributions to science and society. But the vast majority did or achieved nothing and were a drain on resources.
The first wave of globalisation- caused largely by the US ice trade - where taking ice from lakes meant refrigerated train carriages and ice warehouses in Chicago and new York, and refrigerated ships crossing the Atlantic. Suddenly small farms in England, France and Vermont were competing with Iowa corn fields.
There was a 1870s collapse in food prices and the subsequent collapse in social structures - we simply could not afford to keep indolent parsons, and now their “parsonages” are prized second homes
a drain on whose resources?
[1] Percentage of earnings, canonically a tenth, but not sure whether/how much that was always the case.
Look, they had a social organization. Somehow or other, they managed to be the most powerful nation on Earth. It seems sort of idle to nitpick on it.
Personally I put the birth of the Industrial Revolution up There in the top five moments of human history something like
Fire
Domestication of wheat
Wheel
Cortez meeting Montezuma
Industrial Revolution in Northern England of all Places
Whatever it was it happened once. And we have copied it not replicated it (look at Meiji restoration with emperors wearing bowler hats “just in case it helps”.)
We cannot get off this train, so we really need to know how the train works
Would they have a sense of mission - or would they feel entitled and frustrated at the same time? Some would do well of course. But without training, without a calling, it’s not great.
That’s the situation - the social elite of a nation simply sat as mid level church managers.
OK then.
We assume Woodforde (the parson in mid 18 early 19 century England is fairly representative. Yes weddings christenings and burials but mostly … nothing much beyond weather and food.
Did he support a new school, improve the unionisation of the farm workers, yadadada
Society grows or stagnates. Having the elite supported by the majority of workers and then just sitting back and stagnating seems … worthless.
How many of us are pushing in the right direction - that history will look back in two centuries and say “good”
But you do you.
What is our modern understanding of this? Are there kinds of local clusters you could detect with the naked eye?
https://arxiv.org/abs/2311.01865
For naked eye clusters look up pleiadis in the northern emisphere and LMC/SMC in the south, and then you can use stellarium (see other HN post)
> ... it is conceivable that our entire observable universe is a supermassive black hole within a larger universe.
One of my pet peeves is this vague idea about the universe being an infinite fractal, universes inside atoms, etc. It's an appealing idea, but it's totally inconsistent with quantum mechanics and the difference between the strength of forces on different length scales.
Edit: not a physicist by the way, would also love someone who actually knows what they’re talking about to butt in.
Something is falsifiable if you can think up some empirical test that would refute it. That test doesn't need to be feasible. In the case of black hole universes, such a theory may be falsifiable, but we don't know enough about the composition of black holes to even formulate the tests. I'm not a physicist, but my impression is that falsifiability is less important to physics than the ability for a hypothesis to predict and explain observed phenomena.
[1] https://www.salon.com/2020/10/18/why-physics-nobelist-roger-...
> He reasoned that such particles, emerging from the surface of a star, would have their speed reduced by the star’s gravitational pull, just like projectiles fired upward from the Earth. By measuring the reduction in the speed of the light from a given star, he thought it might be possible to calculate the star’s mass.
>Michell asked himself how large this effect could be. He knew that any projectile must move faster than a certain critical speed to escape from a star’s gravitational embrace. This “escape velocity“ depends only on the size and mass of the star. What would happen if a star’s gravity were so strong that its escape velocity exceeded the speed of light? Michell realized that the light would have to fall back to the surface.
Relativity makes black holes much more "final" than this original concept, but he was definitely thinking in the right direction.
If you don't limit yourself to entirely ballistic trajectories you can escape without ever reaching that point's escape velocity.
To explain why nothing, not even things on non-ballistic trajectories, cannot get out of black holes you've got to turn to weird headache inducing general relativity stuff.
It's much easier to think of the gradual warping of spacetime around a black hole so that more and more directions are down. East? No, that's really east and down. Left? Nope, you thought you were going left but it is left and down. Less and less "up" is available to you until you are on a knife edge where you can make an orbit (assuming a non-rotating black hole, no angular momentum) around the event horizon with a photon. Beyond that, everything is some flavor of down.
That when mass becomes high enough that light can't escape nothing else can escape either doesn't pop out of the math until you have general relativity.
Unless the rocket collapses into a black hole under the sheer mass of all that fuel.
One would certainly not expect elementary particles to function like rockets.
But yeah, nobody could come with a description of a black hole anything like the modern one before 1900. Anything older is certain to be very different.
Imagine accelerating an electron in some sort of magnetic field, in series. In a Newtonian system any speed is achievable.
GR forbids this though.
Does it though?
It's not a question of enough mass. It's a question of being compact enough. There is no minimum mass for a black hole, but the smaller the mass, the smaller the surface area of the horizon (the 2-sphere that the mass has to collapse inside to form the hole).
The wave theory of light came quite a bit later, in Maxwell's time.
But he didn't postulate this at all. He simply postulated (as per Newton) that light is made of particles with mass, which could thus be affected by gravity. Since they are moving at a finite speed, the light particles would be slowed down by gravity, and eventually completely stopped.
He further proposed, based on this model, that the mass of an object could potentially be determined by determining how much slower the particles were moving.
This doesn't work. Light doesn't really get slowed down by gravity, and you definitely don't have any slow light that was created from stars trillions of miles away.
It's a cool idea, but doesn't work with how light actually propagates.
Why are Wikipedia contributors hallucinating the meaning of "black complexion"? Apparently since "black people" were not capable of intelligent thought, "black complexion" means "In this case it means he was sad and melancholy".
Do Wikipedia contributors then think that "fair or white complexion" must mean "happy and high-spirited"?
Or is it because all the black people around in the medieval era were uneducated slaves performing menial tasks? What terminology would be used describe the complexion of people of "black African appearance" if "black complexion" meant "sad and melancholy" people?
Charles II was described as "tall black man" when he was on the run during the civil war. I guess those on the look out for him were supposed to look for a tall, "sad and melancholy" looking man, as though that would be a help in picking him out, forgetting that in the middle of a bloody civil war there would be lot of sad people of all heights, shapes and widths out and about.
I would have parsed that as meaning he behaved in a generally dour way.
Since when has the word "description" referred to a person's temperament?
The only time it seems that "complexion" refers to a person temperament is only when if taken literally it refers to a very dark-skinned person or what we call a "black man" in our era, like an African, a Melanesian or a South Asian.
For instance General Monck was described as a "black man" with a sanguine complexion, which should tell you that he was actually a "black man", because sanguine is the reddish-brown, or fawn color that Africans and South Asians exhibit.
Would that mean the "black" used to describe him meant he was sad and melancholy when on the other hand sanguine meant cheerful?
I think you should check the depiction of an English monarch on the frontispiece of Hobbes Leviathan, and also learn about Anton Wilhelm Amo, before concluding that a the term "black complexion" must refer to the temperament of an insightful natural philosopher.
It’s also possible that you’re just a simulation. What is the point? Just to shock.
I think the most likely explanation is that John Michell was a space alien, looking to peddle common knowledge in his galaxy for Earth fame.
https://en.m.wikipedia.org/wiki/George_Green_(mathematician)
Frankly history is replete with bumpkins making extraordinary discoveries. Being a bumpkin is associated with ignorance, not stupidity. Intelligence is pretty uniformly distributed, even among the black, short, fat, and bumpkins.