6 ms·

This argument proves too much. By that same argument, nuclear fission, ordinary CPUs, steam engines, rockets, helicopters, jets, X-rays, radio waves, supercondu

by knzhou 7y ago

This argument proves too much. By that same argument, nuclear fission, ordinary CPUs, steam engines, rockets, helicopters, jets, X-rays, radio waves, superconductivity, superfluidity, air conditioning, liquid helium, liquid nitrogen, the Haber process, the fractional quantum Hall effect, Doppler cooling, graphene, long-distance satellite communication, gravitational waves, and GPS corrections for relativity all don't exist, because nothing in life is designed like them or takes advantage of them. You've literally taken us back to the 1700s. I know that it's fashionable to simply declare quantum computing is impossible, and there are some strong arguments in this direction, but this particular argument isn't one. The general reason people believe quantum computing is possible is that it describes just about all the things I mentioned above absolutely perfectly, along with literally thousands of other phenomena, with no deviations ever measured. This gives us good reason to assume quantum mechanics actually works, and if it does, then it's possible for quantum computing to work. (Also, of course you need to account for quantum mechanics to account for protein folding. You literally can't have chemical bonds at all without quantum mechanics.)

Iv 7y ago
The argument I propose is not a strong one. It is still an argument: if something is possible, why did evolution not use it? There are several possible answers: 1. Life may not have a use for it 2. It may be impossible to achieve with proteins and cells 3. It may not actually be possible For quantum computer I (weakly) believe that 1 and 2 are wrong: evolution and cognition would hugely benefit from quantum acceleration and biology operates at a scale where quantum effects are visible. I thought 3. slightly more likely but I'll readily admit that I am nowhere near the knowledge to be categorical about 2. And note that of the list of things you are giving, there are many that uses the same physical principles that are used by life: steam engine (expansion of heated gases), rockets (ignition of gas), jets (propulsion), helicopters (a rotating wing is a wing), radio waves/X-rays (the RF spectrum, which visible light is part of), etc... The rest, IMO, falls either under 1. or 2. For instance I doubt long-distance communication really offers a substantive advantage when you know whales can already contact each other at 100s of kilometers through shouts, and superfluidity may require conditions and materials that are impossible to reach for organic material. Note however that this last one is actually a kinda good (if weak) argument: if superfluidity was achievable through organic material and conditions close to the temperature and pressure average on earth, life would probably have found it, as it is clearly a useful property. If tomorrow we find that you can get room-temperature superfluids that are made out of C,H and O atoms, wondering why it is not found in nature will be a very good question.
- peteradio 7y ago
  It's 2. There is no way for cell/proteins to maintain a useful small scale quantum state.
- simonh 7y ago
  I don't think 2 is so easy to justify. Quantum state transitions occur all the time in a discordant mess of activity at room temperatures. The only way we can control for that and have quantum transitions occur in useful controlled circumstances is by operating at close to absolute zero, which isn't very conducive to exploitation by terrestrial life. It may turn out to be a similar issue to jet engines, or semiconductors. The materials and conditions required for them to operate just aren't very easy for terrestrial life to evolve into.
- soulofmischief 7y ago
  Nature works on the premise of emergence. It's entirely possible that the energy gradient required for a biological system to make successful, permanent changes beneath its fundamental layer of operation is just too much. Suppose this all started with a few self-replicating proteins. From that we got organelles, and then cells. Then multi-cellular organisms, then tissues, organs, etc. But working backwards, from protein -> molecular chemistry -> quantum phenomenon, may simply not be the path of least resistance and thus for the overwhelming majority of life in the universe, was not an evolutionary path.
- sriku 7y ago
  All that is assuming that you do know for certain the evolution did NOT exploit it. There is some extrapolative argument that hints at the contrary. Adrian Thompson's evolved FPGA circuits exploited a single chip's underlying physics in a manner no digital circuit designer would. By that thread, it would seem possible that evolution has already exploited quantum computation ... just that maybe we haven't had the tech eye to see it yet. After all, all systems are quantum mechanical.
  - smilliken 7y ago
    Rhodopsin, in our retina, exploits a quantun mechanical effect. You could argue that our brains are quantum computers if you consider our retina including rhodopsin to be part of the brain.
raverbashing 7y ago
I think in your list of examples there are plenty of cases where nature, while not building the exact thing uses the same underlying principles. There are a lot of seeds that are aerodynamic so that they get spread more widely for example. Even seeds that have controlled falls due to "autorotation" But of course on planet earth at least it is hard for nature to use things requiring too high or low temperatures. Nature doesn't need the Haber process, but it does fixate nitrogen.
- simonh 7y ago
  Right, so life could make use of quantum transitions that are used in quantum computing, without actually doing or using the results of quantum computations.
- knzhou 7y ago
  If your standards are low enough that you would say superconductivity appears in nature, then quantum computing certainly does.
  - raverbashing 7y ago
    > But of course on planet earth at least it is hard for nature to use things requiring too high or low temperatures So, no, superconductivity probably does not exist in nature
    - knzhou 7y ago
      Most candidates for quantum computing also require extremely low temperatures — in fact, lower than the ones for superconductivity.
kuschku 7y ago
> nuclear fission https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto... For pretty much every thing you list, nature has something pretty close to it in it. Even nuclear fission.
- gilleain 7y ago
  Although natural, that reactor is geological not biological. It's unlikely that enzymes could catalyse fission reactions. It would be amazing if they could...
- knzhou 7y ago
  If you really think you can explain all examples, why did you pick one (by far the easiest one) instead of letting me pick? Let’s see some natural examples that use general relativity, superconductivity, the fractional quantum Hall effect, and superfluidity.
emilfihlman 7y ago
Wtf? Non even remotely the same argument.

by knzhou 7y ago

Iv 7y ago

The argument I propose is not a strong one. It is still an argument: if something is possible, why did evolution not use it? There are several possible answers: 1. Life may not have a use for it 2. It may be impossible to achieve with proteins and cells 3. It may not actually be possible For quantum computer I (weakly) believe that 1 and 2 are wrong: evolution and cognition would hugely benefit from quantum acceleration and biology operates at a scale where quantum effects are visible. I thought 3. slightly more likely but I'll readily admit that I am nowhere near the knowledge to be categorical about 2. And note that of the list of things you are giving, there are many that uses the same physical principles that are used by life: steam engine (expansion of heated gases), rockets (ignition of gas), jets (propulsion), helicopters (a rotating wing is a wing), radio waves/X-rays (the RF spectrum, which visible light is part of), etc... The rest, IMO, falls either under 1. or 2. For instance I doubt long-distance communication really offers a substantive advantage when you know whales can already contact each other at 100s of kilometers through shouts, and superfluidity may require conditions and materials that are impossible to reach for organic material. Note however that this last one is actually a kinda good (if weak) argument: if superfluidity was achievable through organic material and conditions close to the temperature and pressure average on earth, life would probably have found it, as it is clearly a useful property. If tomorrow we find that you can get room-temperature superfluids that are made out of C,H and O atoms, wondering why it is not found in nature will be a very good question.

peteradio 7y ago
It's 2. There is no way for cell/proteins to maintain a useful small scale quantum state.
simonh 7y ago
I don't think 2 is so easy to justify. Quantum state transitions occur all the time in a discordant mess of activity at room temperatures. The only way we can control for that and have quantum transitions occur in useful controlled circumstances is by operating at close to absolute zero, which isn't very conducive to exploitation by terrestrial life. It may turn out to be a similar issue to jet engines, or semiconductors. The materials and conditions required for them to operate just aren't very easy for terrestrial life to evolve into.
soulofmischief 7y ago
Nature works on the premise of emergence. It's entirely possible that the energy gradient required for a biological system to make successful, permanent changes beneath its fundamental layer of operation is just too much. Suppose this all started with a few self-replicating proteins. From that we got organelles, and then cells. Then multi-cellular organisms, then tissues, organs, etc. But working backwards, from protein -> molecular chemistry -> quantum phenomenon, may simply not be the path of least resistance and thus for the overwhelming majority of life in the universe, was not an evolutionary path.
sriku 7y ago
All that is assuming that you do know for certain the evolution did NOT exploit it. There is some extrapolative argument that hints at the contrary. Adrian Thompson's evolved FPGA circuits exploited a single chip's underlying physics in a manner no digital circuit designer would. By that thread, it would seem possible that evolution has already exploited quantum computation ... just that maybe we haven't had the tech eye to see it yet. After all, all systems are quantum mechanical.
- smilliken 7y ago
  Rhodopsin, in our retina, exploits a quantun mechanical effect. You could argue that our brains are quantum computers if you consider our retina including rhodopsin to be part of the brain.

raverbashing 7y ago

I think in your list of examples there are plenty of cases where nature, while not building the exact thing uses the same underlying principles. There are a lot of seeds that are aerodynamic so that they get spread more widely for example. Even seeds that have controlled falls due to "autorotation" But of course on planet earth at least it is hard for nature to use things requiring too high or low temperatures. Nature doesn't need the Haber process, but it does fixate nitrogen.

simonh 7y ago
Right, so life could make use of quantum transitions that are used in quantum computing, without actually doing or using the results of quantum computations.
knzhou 7y ago
If your standards are low enough that you would say superconductivity appears in nature, then quantum computing certainly does.
- raverbashing 7y ago
  > But of course on planet earth at least it is hard for nature to use things requiring too high or low temperatures So, no, superconductivity probably does not exist in nature
  - knzhou 7y ago
    Most candidates for quantum computing also require extremely low temperatures — in fact, lower than the ones for superconductivity.

kuschku 7y ago

> nuclear fission https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor https://en.wikipedia.org/wiki/Natural_nuclear_fission_reacto... For pretty much every thing you list, nature has something pretty close to it in it. Even nuclear fission.

gilleain 7y ago
Although natural, that reactor is geological not biological. It's unlikely that enzymes could catalyse fission reactions. It would be amazing if they could...
knzhou 7y ago
If you really think you can explain all examples, why did you pick one (by far the easiest one) instead of letting me pick? Let’s see some natural examples that use general relativity, superconductivity, the fractional quantum Hall effect, and superfluidity.

emilfihlman 7y ago

Wtf? Non even remotely the same argument.