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In the end, the problem with the claim is that if it is true then 'computer' is defined so loosely as to be uninformative; as soon as you add plausible conditio

In the end, the problem with the claim is that if it is true then 'computer' is defined so loosely as to be uninformative; as soon as you add plausible conditions, it seems obviously false. According to the best physics, the universe: isnt programmable; doesn't evolve deterministically; isnt described by functions over integers; isn't electronic; doesnt transmit power through programmable operation; isn't abstract; doesnt have causal powers through mere arrangements of parts; .. and so on. Whatever it could mean, "computer" here is a strange term. I've no idea why people are so keen on it. I take it to be a sort of humean-idealist-passivist theory: the world is an abstract set of discrete states that are just mere arrangements with no necessary connections; there is only pattern in these discrete states; these patterns are abstract and can be realised by mere number alone. This is roughly somehting like an early 20th C. logicial positivist view, which was somewhat influential -- but it's wholey false, and throw out in scientific practice

optimalsolver 3y ago
>doesn't evolve deterministically Isn't that still debated?
- titzer 3y ago
  Not really. The best models that we have to explain measurable physical phenomenon are wave equations from quantum mechanics that describe probably distributions. There have been proposals for nearly a century that a deterministic model underlies this, but they have to contend with observed phenomenon and inconveniences like Bell's Theorem that suggest that our universe just isn't deterministic. That said, we don't have a unified theory of the universe. General relativity, the dark matter question, and quantum mechanics have not been unified into any mathematical theory. All of those theories are pretty weird, mathematically. And we have no efficient way to simulate on classical computers the models that we do have. We don't live in a billiard ball universe. It's a CS fantasy that evaporates as soon as you start doing experiments on matter and energy in the actual universe we are in.
  - mjburgess 3y ago
    Yes, the biggest problem with this mere mechanistic picture is why anything should move at all. The csci view is essentially a divine command one: the machine runs because of it's 'program' which is somehow external to the machine. But this is a metaphor/illusion for programmable devices like electronic computers, which breaks down for the actual universe. The universe must be inherently dynamical, ie., not mere discrete states that change by rules, but properties whose nature is to interact with the world... This is why the abstract mathematical conception of "computer" cannot describe anything physical: mathematical objects do not have temporal properties; they do not change. This leads to the illusion, for electric devices, that the change is extrinsic to the physics of the system since we can specify the algorithm (somewhat) abstractly. But it isnt.. your pieces of meat, are in the end, the causal power which moves the liquid crystal, electric field, etc.
    - fellowmartian 3y ago
      I think this a caricature or at least a shallow view of computationalism. Nobody is claiming that the universe is a computer of the same kind as the ones we have. Instead, I think, it claims that the universe has to necessarily be computational in order to be real - everything has to be computational to be real, otherwise how can it ever be implemented. On your "divine command" bit: I don't think any theory has a good claim on the ultimate ontology of reality, so I don't see how one view is better than another. It's all some kind of divine command at the moment. Computationalism at least constrains the necessary properties the divine must have.
      - titzer 3y ago
        > everything has to be computational to be real But that's just circular logic. It begs the question as to what is "computational" and what is "mathematical". E.g. Tegmark has good points in the "Mathematical Universe" that describe possible interpretations of what it means to be mathematical. But how is computation different than math? I'd argue that computation is primarily stateful, logical, and (mostly) deterministic with a clear flow of time, whereas mathematical models are often time-reversible (as most, if not of QM is), stateless, and not necessarily "logical" in the sense of relating finite symbolic quantities. Rather mathematical models happily relate infinite series, manifolds, surfaces, high-dimensional spaces, they talk about fields and operate on functions, etc.
madisp 3y ago
Isn't the universe the only computer in some sense? All of the compute power we have is just an arrangement of matter to have the universe perform computations for us.
- mjburgess 3y ago
  I don't regard computation as a physical process, or a property of any kind. It's a description of a system, say like "salad" or "party", which whilst informative in conversation, doesn't map to any actual property of reality. ie., there is no property shared by all salads, nor by all computers. Saying, "everything is a computer" is a bit presocratic in its way, like "everything is water" or "everything is fire" In practice, what we mean by "computer" is something which can transmit power in a programmable fashion.. this has more to do with our ability to control devices, and what those devices are, than anything in the "computer". It turns out LCDs, keyboards, CPUs, etc. can all be joined up so I can do something with them.. I call this a "computer" and leave it there. As far as the mathematical definition goes, all functions from ints->ints are computable.. this is eitehr useless or uniformative. It has no relevance for physics.
- taneq 3y ago
  From that point of view, all the other matter is also a computer, it's just for the most part computing really boring functions.
- bigboy12 3y ago
  How is it not electric?? You have trillions of fields and particle’s everywhere. How’s it not programmable? It’s computing new structures with gases at any moment.
  - exe34 3y ago
    The electric part seems an arbitrary limitation. The original computers ran off food, which okay technically is chemistry which technically is just a minor application of coulomb's law, but ultimately you can use stones in the desert or water flowing through pipes to compute. Of course all this is still based off chemistry, but you can imagine computing with gravity or nuclear forces.
figassis 3y ago
What would happen if you could build an artificial being that was capable of taking in input (action) and provide output (reaction). I don’t think predictability should be a defining property of computers, or we would not be trying to build AI. How components interact with each other, or how it is powered should also not define a computer. Your brain is a computer and we still don’t have much of a clue how it works. We started computing with rudimentary tools and then kept extending that model to what it is today. What would happen if our concepts were entirely different?
- mjburgess 3y ago
  So you're working backwards from the claim that reality is a computer to defining computer. Yes, by the time you enumerate all the properties of reality, and call them a "computer", you'll find that this is not a computer in the sense of computer science.
  - exe34 3y ago
    That's a bit like determining a ship can only be made of wood, isn't it? A ship needs to float, it needs to be made of buoyant material and it needs to have a sail. If a "sailor" is adjusting the power to a propellor that's turned by an electric motor that's running off a turbine driven by steam from a magical rock, it's not what we define as naval science, is it?
    - goatlover 3y ago
      The thing missing here is that it's only a ship for humans. Ships are cultural artifacts. If we said the universe was a ship that was sailing itself, that would be misapplying something we make for nature itself. Independent of human culture, ships are just arrangements of matter. We make particular arrangements meaningful. Same thing applies to computers and computation. It's only meaningful to use those words for matter we arrange to do certain stuff for us.
      - exe34 3y ago
sesteel 3y ago
I was taught the universe was a computer in 3 different college courses 25 years ago. Not exactly a revelation. "According to the best physics, the universe: isnt programmable; doesn't evolve deterministically; isnt described by functions over integers; isn't electronic; doesnt transmit power through programmable operation; isn't abstract; doesnt have causal powers through mere arrangements of parts; .. and so on." You can't say any of these things because electronic computers exist within the universe, but I get what your point is. That said, there are physicists beginning to assume the universe IS a computer and work forward from that assumption.
pasquinelli 3y ago
before computers were programmable, there were still computers. before they were machines, there were computers. a computer is a thing that carries out a computation. obviously, the universe computes spacetime. but i agree, that's not an interesting fact.
- constantcrying 3y ago
  If an abacus is a computer, then the term is near meaningless and quite unhelpful.
random3 3y ago
perhaps the problem is you're trying to fit computer in the wrong level of abstraction or projecting your position wrt to it incorrectly. E.g. a computer may or may not be programmable for processes that live inside the computer. This said, the compute abstraction is a logical gadget. Logical in the sense that it aims for consistency at a mininmum. A logical gadget is a computer, by Curry-Howard correspondence. This is a broad enough framework to explain why what you're debating against is the case: given that philosophy bridges language to logic and provies the framework for all sciences, seeing nature as compute is like saying there's a logic to nature. So yes, everything is compute. Everything more detailed that that, turing machines, digits, whether it's it from bit or not is a separate matter of debate that may or may not be required.
- Al0neStar 3y ago
  > everything is compute. Isnt this the problem OP is referring to? If everything is compute then no useful distinction can be made.
  - random3 3y ago
    The utility is relative to the purpose. If everything is compute that you don't know how to program, and that's all you want to do - sure that's useless. If you what you want is a powerful analysis framework, that's gold. If you know how to abstract your way forward with that framework that too. So arguing that the distinction is useless because it's universal, is like saying logic is useless because it's universal.
croutons 3y ago
The article clearly states that it’s using our colloquial meaning of “computer” as a metaphor to help convey their thought experiment. It even has a disclaimer about using metaphors. FWIW I think it’s an interesting thought experiment. I think it’s especially interesting to draw the parallel to biology. Clearly our brains are doing computation by even the strictest definition of computer, so at which biological level does computation stop? A chunk of my brain is clearly doing computation, a neuron must be doing computation since that is the building block for our brains. Single cells must also be doing computation since a single cell had all of the computational knowledge encoded in it to build me. All of these processes are built upon physical reality, so it’s not that big a leap that similar processes might emerge elsewhere and at different scales and using different physical mechanisms.

optimalsolver 3y ago

>doesn't evolve deterministically Isn't that still debated?

titzer 3y ago
Not really. The best models that we have to explain measurable physical phenomenon are wave equations from quantum mechanics that describe probably distributions. There have been proposals for nearly a century that a deterministic model underlies this, but they have to contend with observed phenomenon and inconveniences like Bell's Theorem that suggest that our universe just isn't deterministic. That said, we don't have a unified theory of the universe. General relativity, the dark matter question, and quantum mechanics have not been unified into any mathematical theory. All of those theories are pretty weird, mathematically. And we have no efficient way to simulate on classical computers the models that we do have. We don't live in a billiard ball universe. It's a CS fantasy that evaporates as soon as you start doing experiments on matter and energy in the actual universe we are in.
- mjburgess 3y ago
  Yes, the biggest problem with this mere mechanistic picture is why anything should move at all. The csci view is essentially a divine command one: the machine runs because of it's 'program' which is somehow external to the machine. But this is a metaphor/illusion for programmable devices like electronic computers, which breaks down for the actual universe. The universe must be inherently dynamical, ie., not mere discrete states that change by rules, but properties whose nature is to interact with the world... This is why the abstract mathematical conception of "computer" cannot describe anything physical: mathematical objects do not have temporal properties; they do not change. This leads to the illusion, for electric devices, that the change is extrinsic to the physics of the system since we can specify the algorithm (somewhat) abstractly. But it isnt.. your pieces of meat, are in the end, the causal power which moves the liquid crystal, electric field, etc.
  - fellowmartian 3y ago
    I think this a caricature or at least a shallow view of computationalism. Nobody is claiming that the universe is a computer of the same kind as the ones we have. Instead, I think, it claims that the universe has to necessarily be computational in order to be real - everything has to be computational to be real, otherwise how can it ever be implemented. On your "divine command" bit: I don't think any theory has a good claim on the ultimate ontology of reality, so I don't see how one view is better than another. It's all some kind of divine command at the moment. Computationalism at least constrains the necessary properties the divine must have.
    - titzer 3y ago
      > everything has to be computational to be real But that's just circular logic. It begs the question as to what is "computational" and what is "mathematical". E.g. Tegmark has good points in the "Mathematical Universe" that describe possible interpretations of what it means to be mathematical. But how is computation different than math? I'd argue that computation is primarily stateful, logical, and (mostly) deterministic with a clear flow of time, whereas mathematical models are often time-reversible (as most, if not of QM is), stateless, and not necessarily "logical" in the sense of relating finite symbolic quantities. Rather mathematical models happily relate infinite series, manifolds, surfaces, high-dimensional spaces, they talk about fields and operate on functions, etc.

madisp 3y ago

Isn't the universe the only computer in some sense? All of the compute power we have is just an arrangement of matter to have the universe perform computations for us.

mjburgess 3y ago
I don't regard computation as a physical process, or a property of any kind. It's a description of a system, say like "salad" or "party", which whilst informative in conversation, doesn't map to any actual property of reality. ie., there is no property shared by all salads, nor by all computers. Saying, "everything is a computer" is a bit presocratic in its way, like "everything is water" or "everything is fire" In practice, what we mean by "computer" is something which can transmit power in a programmable fashion.. this has more to do with our ability to control devices, and what those devices are, than anything in the "computer". It turns out LCDs, keyboards, CPUs, etc. can all be joined up so I can do something with them.. I call this a "computer" and leave it there. As far as the mathematical definition goes, all functions from ints->ints are computable.. this is eitehr useless or uniformative. It has no relevance for physics.
taneq 3y ago
From that point of view, all the other matter is also a computer, it's just for the most part computing really boring functions.
bigboy12 3y ago
How is it not electric?? You have trillions of fields and particle’s everywhere. How’s it not programmable? It’s computing new structures with gases at any moment.
- exe34 3y ago
  The electric part seems an arbitrary limitation. The original computers ran off food, which okay technically is chemistry which technically is just a minor application of coulomb's law, but ultimately you can use stones in the desert or water flowing through pipes to compute. Of course all this is still based off chemistry, but you can imagine computing with gravity or nuclear forces.

figassis 3y ago

What would happen if you could build an artificial being that was capable of taking in input (action) and provide output (reaction). I don’t think predictability should be a defining property of computers, or we would not be trying to build AI. How components interact with each other, or how it is powered should also not define a computer. Your brain is a computer and we still don’t have much of a clue how it works. We started computing with rudimentary tools and then kept extending that model to what it is today. What would happen if our concepts were entirely different?

mjburgess 3y ago
So you're working backwards from the claim that reality is a computer to defining computer. Yes, by the time you enumerate all the properties of reality, and call them a "computer", you'll find that this is not a computer in the sense of computer science.
- exe34 3y ago
  That's a bit like determining a ship can only be made of wood, isn't it? A ship needs to float, it needs to be made of buoyant material and it needs to have a sail. If a "sailor" is adjusting the power to a propellor that's turned by an electric motor that's running off a turbine driven by steam from a magical rock, it's not what we define as naval science, is it?
  - goatlover 3y ago
    The thing missing here is that it's only a ship for humans. Ships are cultural artifacts. If we said the universe was a ship that was sailing itself, that would be misapplying something we make for nature itself. Independent of human culture, ships are just arrangements of matter. We make particular arrangements meaningful. Same thing applies to computers and computation. It's only meaningful to use those words for matter we arrange to do certain stuff for us.
    - exe34 3y ago

sesteel 3y ago

I was taught the universe was a computer in 3 different college courses 25 years ago. Not exactly a revelation. "According to the best physics, the universe: isnt programmable; doesn't evolve deterministically; isnt described by functions over integers; isn't electronic; doesnt transmit power through programmable operation; isn't abstract; doesnt have causal powers through mere arrangements of parts; .. and so on." You can't say any of these things because electronic computers exist within the universe, but I get what your point is. That said, there are physicists beginning to assume the universe IS a computer and work forward from that assumption.

pasquinelli 3y ago

before computers were programmable, there were still computers. before they were machines, there were computers. a computer is a thing that carries out a computation. obviously, the universe computes spacetime. but i agree, that's not an interesting fact.

constantcrying 3y ago
If an abacus is a computer, then the term is near meaningless and quite unhelpful.

random3 3y ago

perhaps the problem is you're trying to fit computer in the wrong level of abstraction or projecting your position wrt to it incorrectly. E.g. a computer may or may not be programmable for processes that live inside the computer. This said, the compute abstraction is a logical gadget. Logical in the sense that it aims for consistency at a mininmum. A logical gadget is a computer, by Curry-Howard correspondence. This is a broad enough framework to explain why what you're debating against is the case: given that philosophy bridges language to logic and provies the framework for all sciences, seeing nature as compute is like saying there's a logic to nature. So yes, everything is compute. Everything more detailed that that, turing machines, digits, whether it's it from bit or not is a separate matter of debate that may or may not be required.

Al0neStar 3y ago
> everything is compute. Isnt this the problem OP is referring to? If everything is compute then no useful distinction can be made.
- random3 3y ago
  The utility is relative to the purpose. If everything is compute that you don't know how to program, and that's all you want to do - sure that's useless. If you what you want is a powerful analysis framework, that's gold. If you know how to abstract your way forward with that framework that too. So arguing that the distinction is useless because it's universal, is like saying logic is useless because it's universal.

croutons 3y ago

The article clearly states that it’s using our colloquial meaning of “computer” as a metaphor to help convey their thought experiment. It even has a disclaimer about using metaphors. FWIW I think it’s an interesting thought experiment. I think it’s especially interesting to draw the parallel to biology. Clearly our brains are doing computation by even the strictest definition of computer, so at which biological level does computation stop? A chunk of my brain is clearly doing computation, a neuron must be doing computation since that is the building block for our brains. Single cells must also be doing computation since a single cell had all of the computational knowledge encoded in it to build me. All of these processes are built upon physical reality, so it’s not that big a leap that similar processes might emerge elsewhere and at different scales and using different physical mechanisms.