COLLOQUIUM: 'The Physics of Can and Can’t': from the universal computer to the universal constructor 

You all prolly dont care at all but does any of you know of a way to get back into an instagram account?? I somehow forgot my account password. I appreciate any tricks you can give me!

@Kolton Jase Instablaster =)

@Jamie Genesis thanks so much for your reply. I found the site thru google and Im trying it out now. Takes quite some time so I will reply here later when my account password hopefully is recovered.

@Jamie Genesis it worked and I finally got access to my account again. I'm so happy:D Thanks so much you really help me out!

@Kolton Jase glad I could help xD

I think their point is that a Turing Machine is insufficient for predicting the world around us, in particular the rich area that lies between very simple systems and very complex or chaotic systems. I'm not sure.

@@david203 The question is: will it in principal be programmable (by whom) or will it just „somehow“ (BlackBox) gather data and TheSolution pops up after some time (42? Who will understand/believe/use such a solution? Is it neccessary that someone/something u/b/u it?)

@@waltertanner7982 Well, these are excellent questions. Unfortunately, the videos on Constructor Theory are so long-winded and vague that we have no idea what the answers are. I guess the founders (David Deutsch, et.al.) want to transform physics from a random collection of experimental and theoretical knowledge to, well, something else, I guess. See en.wikipedia.org/wiki/Constructor_theory, which speaks of "abstract specifications of transformations in terms of input/output pairs of attributes," whatever that means. All I can say is that if it can predict the way a creature looks and acts based on its DNA, or, even better, if it can design DNA to create a creature that looks and acts according to a specification, then it is most certainly successful in answering questions that physics is not even ready to ask. We shall see.

She specifically says in the lecture that a Turing Machine is not a universal computer, because it cannot create a copy of itself. So a Turing Machine cannot do what a living cell does. So it is not universal.

@@uazuazu I certainly agree. Turing Machines have to do only, ONLY with the computation of algorithms, step by step operations that end by halting. Nothing else. While computation is interesting and useful, it is not the whole operation of nature, or the whole province of physics. I wish the Constructor Theorists great luck, which they will need since they offer no actual construction that duplicates nature in any new way. Correct me, someone, if I'm wrong, but it all seems to be just words. After ten years of preparation, it's still just words. I want to know which cellular automata generate chaotic behavior, just by inspecting the automata rules. I want to know how to construct DNA that will build a given structure made up of proteins. Isn't this the province of Constructor Theory? And if the Constructor theorists are so innovative, how come they don't embrace the de Broglie-Bohm interpretation of quantum mechanics, which has been validated by experiment and solved QM's basic problems and eliminated its mysteries back in 1952?

Hm, maybe "conservation of energy" is just a name for the law of physics that "perpetual motion machines are impossible". What perpetual motion is, is also not really clear to me but I guess it can be more easily defined using transformations of substrates than energy.

Is it not like an engine of the possible?

It is a time evolution conserved quantity of a system whose differential is proportional to the work.

How can we do that?that is a huge information.

@@gaminghunt5837 Agreed. But there is a lot of speculation about how powerful future generations of quantum computers could be. If the 'many worlds' interpretation of QD turned out to be correct (big if), quantum computers might effectively be limitless (i.e. Infinite parallel processing).

@@audiodead7302 but how will we connect the computers together?what will we do if the computers malfunction?Chaos is everywhere.

Hope that's not the case. Radical ideas are always met with skepticism that lacks argument.

@@peaku8129: I'd be happy to be proven wrong, but I'm skeptical of grandiose claims, such as the ones by the authors involved in that theory, especially if they're accompanied by a lot of words instead of a lot of peer reviewed papers and clearly stated results. But never say never...

@@rv706 it is theoretical physics at it's most theoretical. I am curious, what sort of clearly stated results from papers do you expect?

@@greycookie666: Idk, is it at least possible to rederive quantum mechanics from constructor theory? If yes, is this done seriously or is it just handwaving? - Does CT make any testable predictions? --- I'm not familiar with CT, but in words it is said to obtain "everything" (quantum mechanics, thermodynamics, ...) and I am skeptical of things that are claimed to do everything.

@@rv706 nobody knows for sure where this theory is going. I guess the right attitude is to be an skeptic-optimist: Take every argument with a grain of salt, but be positive towards its development.

Where is the energy going in that case? It's going to the environment. The machine in one direction is turning potential energy into heat energy. It cannot go in the reverse direction and turn heat energy into potential energy. What you're talking about is a completely different "reverse" transformation which isn't a reverse transformation at all: where potential energy is used to move heat energy from the container to the environment.

@@uazuazu What if there is no atmosphere around the machine that I described ? Pulling the cylinder of the piston will increase the volume of the gas under the piston. That will cool the gas and there is no heat generated, quite the opposite : the gas will absorb the heat of the surrounding parts and the total amount of heat will be smaller. The machine X she described has been specifically chosen so it cannot reverse heat, but that does not prove it's impossible. It's not a fundamental law.

@@En_theo Still, the machine you describe is not the reverse of the original machine. It does not take the end-state back to the starting state.

@@uazuazu Actually it does, by compressing the air (the compressed air will have an elastic reaction) and the system will. But that's not what she explained, she compared the fact that stirring backwards could not cool the system and don't forget that system X and Y are two devices, not the same device in different states. As I said, she chose a machine (stirring) specifically so that it cannot be reversed. But that is meaningless, since her point is that reversibility was universally "impossible" while it's just impossible with "that" machine. So I still don't see the point here, maybe she forgot to explain a part that was obvious to her but not to the public.

A perpetual energy machine is impossible, that’s the “constructer” rule! Ask yourself Why is that? What physical rules apply? 🤯🤯🤯🤯🤯

Nice. It only works as long as other peoples' money drives it though, so it's the same thing, isn't it?

If it had more maths then it would not be a generalist lecture for interested laymen but a specialist one for qualified people. Did you simply not listen to her introductory remarks or were you at the time too busy working on your comment? If you are just so much better than she is at giving these sorts of lectures where is your channel, never mind your PhD XD

The whole point is to see what you can derive without getting into the details. It seems that they have already derived some useful results, e.g. predicting that if a gravitational field can be used to entangle quantum bits, then gravity must be non-classical (at least partly). So if that gravity experiment can be done (or observed in the cosmos somehow) and other people agree with the reasoning, then that takes physics one step forward.

TM, I find it odd that you should say this about engineers & physicists... notions like Fermat distributions, delta functions and their derivatives & integrals, orthogonal transformations of density functions, imaginary density functions (i.e. probability amplitudes), probabilities as solutions of integro-differential equations, all statistical mechanics, all thermodynamics, and on and on and on... were all developed by physicists decades (or longer) before engineers used them. (Your use of the term 'word salad' to describe a probability procedure that is well established in physics should be a warning sign to you. BTW, QM now has at least 9 diffeomorphically homologous representations that can produce calculations homomorphic to the Born rules.) My general rule-of-thumb used to be that physicists were about 50 years ahead of engineers in matters of theory, and I suppose this is still more or less the case. The good news is that engineers have a huge refreshing pool of futuristic ideas from which to quench their thirst. Drink deeply and enjoy.

@@rexdalit3504 Let me explain! Physicists did indeed develop statistical mechanics at an early stage - but critically this was before Kolmogorov's formulation of probability theory in the 1930's and the subsequent development of stochastic processes. Instead they continued to use primitive concepts such as "ensembles". It is quite telling that your list of mathematical tools are mostly 19th century (did you just make up Fermat distributions?): measure theory and abstract integration don't make your list (essential for modern probability theory), nor W*-algebras which is the noncommutative analogue. Engineers adopted the correct mathematical approach to describing noise and extracting information and subsequently controlling systems from the 1960's onwards as can be seen in the work of Kalman, Kushner, Stratonovich, Zakai, etc. Are you familiar with these? The quantum extension was worked out in the 1980's, but physicists still mess around with "collapse of the wave-function". The primitive conceptualization of probability used by physicists is problematic and is wholly inadequate for formulating and addressing practical problems solved by engineers - and this extends to quantum to. Talking about word-salads, can you give any of the "diffeomorphically homologous representations that can produce calculations homomorphic to the Born rules"?

I think it’s the shaper theory of Plato.

@@KRYMauL You mean the Theory of Forms?

@@carloscastanheiro2933 Yes, I think that’s essentially what this is.

@@KRYMauL I don't know, I think that's just a tiny portion of it. She talks about Quamtum computers and it feels so complex to me.

@@carloscastanheiro2933 That’s just an example.

I could easily understand her and English is not even my first language...

@@JJviniciuss ok, and? I don’t see how your understanding helps me understand her. And why are you assuming English is my first language? It’s my fifth.

@@hudatolah what I am saying is not that me understanding makes it easier for you. Is that you may not be fluent enough on the listening aspect of the language. And that would make sense since, as you said, English is your fifth language. Also, I never once assumed English was your first language... I never said that.

@@hudatolah If you can't understand her English, which is clear and understandable, you probably shouldn't complain that it's other people's fault.