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> Nature is probabilistic, and seems to work. I think what you mean is that the currently most successful model of the physical world is probabilistic, but thi

> Nature is probabilistic, and seems to work. I think what you mean is that the currently most successful model of the physical world is probabilistic, but this doesn't mean that nature is.

sillysaurusx 6y ago
Mm. That's an interesting way of looking at it. But the assumptions are laid out by Feynman: https://www.youtube.com/watch?v=QRE0GxT6Zbw&list=PLgRI7D_FXEnrCM8T1czHfJsvbQd4V1jRc&ab_channel=L%27Universitaire https://www.youtube.com/watch?v=QRE0GxT6Zbw&list=PLgRI7D_FXE... Although I'd love to urge everyone to sit through all six hours, I recognize this isn't too practical. So -- with apologies to Feynman -- I'll have to do a poor job of translating: - The scientific method means that we are never certain we're right; we're only certain we're wrong. But (as with Newton's laws) it's pretty incredible we can last so long before we're proven incorrect! - The world seems to obey mathematics. But math != physics. One helps the other; discoveries in math have applied to physics, and vice-versa. - The heart of nature seems to be a purely mathematical construct, from which there is no escape. Many people have tried to model gravity as something other than the gravitational equation, e.g. suppose at every point in time there are particles shooting every direction simultaneously. Then gravity is merely us blocking these particles -- earth with respect to the sun blocks a certain fraction of particles towards the sun, and in fact inversely as the square of the distance. No math necessary! Unfortunately, doesn't quite work -- if it were true, the earth would have slowed in its orbit due to blocking the particles, and it wouldn't have lasted ~billions of years. So that's the end of that theory. - The double slit experiment seems to prove that the world has no other model other than probabilistic (see lecture 6). There is some fundamental limitation preventing us from narrowing down nature further than this threshold. - Every test designed to break this assumption has failed. Therefore, I say that the physical world is probabilistic, and I will wager any sum of money you'd like to bet that it will still be true within, say, 200 years. There is one interesting alternative: if everything in the universe is pre-destined. The complete absence of any kind of free will whatsoever. Every atom, every electron, every single subatomic particle, all predestined from the moment of the big bang til now. That seems to be the only way that it can't be probabilistic.
psychoslave 6y ago
Yes, I completely agree. I think however that the point was that whatever we build out of our best available physical theories ultimately relies on probabilistic grounds. Now on the other hand, we don't use quantum physics for every single human project out there, and for many human scale phenomena, we can act without concious probabilistic representations.
bawolff 6y ago
Have the right cosmic ray hit the right set of memory chips, and you will be super rich. That can happen in an entirely deterministic world. I think its important to distinguish between realistic probabilities and unrealistic probabilities. If the chance is 2^-100 %, nobody cares. Bitcoin is a lot less secure than that, but its still not something i realistically would worry about.

> Nature is probabilistic, and seems to work. I think what you mean is that the currently most successful model of the physical world is probabilistic, but this doesn't mean that nature is.

sillysaurusx 6y ago

Mm. That's an interesting way of looking at it. But the assumptions are laid out by Feynman: https://www.youtube.com/watch?v=QRE0GxT6Zbw&list=PLgRI7D_FXEnrCM8T1czHfJsvbQd4V1jRc&ab_channel=L%27Universitaire https://www.youtube.com/watch?v=QRE0GxT6Zbw&list=PLgRI7D_FXE... Although I'd love to urge everyone to sit through all six hours, I recognize this isn't too practical. So -- with apologies to Feynman -- I'll have to do a poor job of translating: - The scientific method means that we are never certain we're right; we're only certain we're wrong. But (as with Newton's laws) it's pretty incredible we can last so long before we're proven incorrect! - The world seems to obey mathematics. But math != physics. One helps the other; discoveries in math have applied to physics, and vice-versa. - The heart of nature seems to be a purely mathematical construct, from which there is no escape. Many people have tried to model gravity as something other than the gravitational equation, e.g. suppose at every point in time there are particles shooting every direction simultaneously. Then gravity is merely us blocking these particles -- earth with respect to the sun blocks a certain fraction of particles towards the sun, and in fact inversely as the square of the distance. No math necessary! Unfortunately, doesn't quite work -- if it were true, the earth would have slowed in its orbit due to blocking the particles, and it wouldn't have lasted ~billions of years. So that's the end of that theory. - The double slit experiment seems to prove that the world has no other model other than probabilistic (see lecture 6). There is some fundamental limitation preventing us from narrowing down nature further than this threshold. - Every test designed to break this assumption has failed. Therefore, I say that the physical world is probabilistic, and I will wager any sum of money you'd like to bet that it will still be true within, say, 200 years. There is one interesting alternative: if everything in the universe is pre-destined. The complete absence of any kind of free will whatsoever. Every atom, every electron, every single subatomic particle, all predestined from the moment of the big bang til now. That seems to be the only way that it can't be probabilistic.

psychoslave 6y ago

Yes, I completely agree. I think however that the point was that whatever we build out of our best available physical theories ultimately relies on probabilistic grounds. Now on the other hand, we don't use quantum physics for every single human project out there, and for many human scale phenomena, we can act without concious probabilistic representations.

bawolff 6y ago

Have the right cosmic ray hit the right set of memory chips, and you will be super rich. That can happen in an entirely deterministic world. I think its important to distinguish between realistic probabilities and unrealistic probabilities. If the chance is 2^-100 %, nobody cares. Bitcoin is a lot less secure than that, but its still not something i realistically would worry about.