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As I understand it, the uncertainty principle implies actual, rather than measured, uncertainty of complementary variables. I recently heard an argument which stated that quantum indeterminacy is consistent with the theory of simulated reality because such uncertainty prevents an arbitrary amount of information being extracted from even one particle's variables, thus allowing simulation without infinite resources.

In general, what would a universe without uncertainty be like? More specifically, could intelligent life exist in such a universe and use technology?

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closed as primarily opinion-based by user10851, John Rennie, CuriousOne, Qmechanic Aug 2 '16 at 8:45

Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.

  • $\begingroup$ Immediately after posting this question, I found this exact question on the World building Stack Exchange. Still, perhaps someone could elaborate more here. $\endgroup$ – S. Hale Aug 2 '16 at 3:26
  • $\begingroup$ It would imply that the momentum and position operators of every particle commute with one another. Taking the limit to newtonian physics... $\endgroup$ – dualredlaugh Aug 2 '16 at 3:33
  • $\begingroup$ I see the argument, but I don't agree with that. Like stated in the comment above, your case corresponds to nothing but classical mechanics. Classical mechanics is much either to simulate (on a computer) than quantum mechanics. $\endgroup$ – pathintegral Aug 2 '16 at 3:47
  • $\begingroup$ We have been unable to construct stable matter models without assuming the structure of quantum mechanics, so, at least from what we know about how nature expresses itself (with symplectic manifolds), it's either uncertainty or a pretty boring (empty) place. $\endgroup$ – CuriousOne Aug 2 '16 at 5:04
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Perhaps the most catastrophic consequence of removing quantum uncertainty would be the instability of atoms

As we understand them, electrons are attracted to nuclei due to their opposite electric charges. However, electrons do not orbit the nucleus like planets around a star; the uncertainty principle precludes electrons from orbiting in definite paths. Instead, electrons exist in an smeared-out cloud of probability around the nucleus. The cloud can change shape and energy when hit by photons or other particles, but for the most part this cloud is unchanging. The technical name for this cloud is orbital and is a specific kind of quantum wavefunction.

The fact that the orbitals are stationary is very important because accelerating electric charges emit radiation (look up bremsstrahlung radiation and synchrotron radiation). Without quantum uncertainty, an orbiting electron emits radiation because a circular orbit requires the electron to accelerate towards the nucleus. This acceleration causes the electron to emit radiation, which causes the electron to lose energy and fall closer to the nucleus. The in-falling electron orbits the nucleus faster and faster, emitting radiation at faster and faster rate until it collides with the nucleus in less than a nanosecond.

If our universe were born without quantum uncertainty, approximately 380,000 years after the big bang, every electron in the universe would have merged with every proton, leaving the universe populated with nothing but neutrons, photons, and neutrinos for all eternity. I don't see how intelligent life could form from such non-interacting entities.

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Quantum indeterminacy is inherent in quantum mechanics. The Heisenberg uncertainty is in the core of the quantum dynamics.

If the underlying level of nature were not quantum mechanical, it would be newtonian, and then bound states would not exist:electrons and protons would neutralize each other, chemistry would not exist as there would be no atoms, etc etc. Information would be irrelevant because there would be nobody to worry about it.

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