More and more philosophers and scientists speculate that the basis of reality could be information, however there is something that does not come back to me in this line of reasoning: information is a resolution of uncertainty. Information seems to make no sense when taken alone, and to say that information is the basis of reality seems to logically imply that uncertainty is actually at the ground. Can anyone help me clarify this?

  • Simply understood, information is difference or contrast. The only reason 1 exists is because things that are not 1 exist. The only reason I exist is because things that are not I exist. So whatever you can measure empirically(with your senses) or reason about, you are performing a practice in distinguishing. The universe allows such a distinguishing to take place, hence it is reasonable to assume that the universe is made of information. And yet, information has the connotation of perception linked to it, which warrants further investigation.
    – Weezy
    Jun 2, 2020 at 10:25
  • Just as uncertainty/probability can be interpreted subjectively, as measures of subject's lack of information, and objectively, in terms of physical propensities (see SEP, Interpretations of Probability), so too can be the information. The proposers of information as the basis of reality, like Wheeler, Lloyd or Davies, opt for the objective interpretation. One can think of it as a form of idealism, but unlike the ideal of old theirs has quantifiable behavior and physical effects.
    – Conifold
    Jun 3, 2020 at 5:03

1 Answer 1


It is. Look at the uncertainty principle.

So, entropy is a multi-faceted concept mainly because, it applies where we can see all the moving parts, and also in matter where there are of the order 10^23 parts and many more states.

The information- or Shannon-entropy is defined in terms of signal loss on transmission through a channel, and this has been proven to be equivalent to thermodynamic entropy. In that technical sense, information can be defined as the inverse of entropy. And that is typically what is meant by everything is information - although information is also used in other senses even by those same physicists, causing confusion (for example, constraints, symmetries). The closest to the big bang we can see had the greatest degree of certainty about the state of the most matter; that is an equivalent description to saying it was in a high entropy state. It must be noted entropy is always relative, it is only meaningful in comparing states.

Entropy was long treated as a secondary property of matter, or mass-energy. But with relativity being about information propagation as limited to the speed of light, and quantum mechanics having the uncertainty principle defining quantum behaviour, information transfer & uncertainty is clearly fundamental to the behaviour of physical systems. It can be argued that modern physics is property-dualist, between mass-energy & information, and the expected resolution of those into a single description of mass-energy + initial conditions to provide a complete description in classical physics, has now shifted to an expectation that mass-energy will be subsumed into a more fundamental information space description. Mass is now described as interaction with the Higgs field. That just leaves space-time & the effect of mass on it, to unify all the known fields.

The programme to quantise the classical theory of gravity has failed, but space-time in quantum field theory only appears as unexamined background. So interest is now shifting to how space-time might be emergent from a quantum description.

Chiribella has proposed the 'purification principle', that increase of entropy is equivalent to the spreading out of information, or mixing of states that need to be known for a complete description. The conservation of information is increasingly speculated to be a universal principle by Susskind & others, because that would resolve the blackhole information paradox. Blackholes seem to have the highest density of states possible, another way of saying maximum entropy, behaving as a kind of frictionless superfluid inside the event horizon. Time there behaves so strangely that it's likely observations will be needed to move forward, like through gravity-wave observatories.

There are many professional physicists who give the information-as-fundamental view short shrift, eg Sean Carroll. It is intuitively appealing, but can certainly be argued that it just restates what was always known, to do physics we want to compare states of systems at different times, so we gather & compare information, and contrast.

  • 1
    Why do you say Sean Carroll gives it short shrift? In this post he discusses a proposal where spacetime is not fundamental but emerges from a picture where we divide a quantum state in Hilbert state into 'pieces' and then 'Use quantum information — in particular, the amount of entanglement between different parts of the state, as measured by the mutual information — to define a “distance” between them. Parts that are highly entangled are considered to be nearby, while unentangled parts are far away.'
    – Hypnosifl
    Jun 2, 2020 at 21:27
  • @Hypnosifl: Yeah I think that approach is extremely promising. Here he is stating exactly what he is sceptical about though youtu.be/SRd0IY23baA
    – CriglCragl
    Jun 2, 2020 at 23:49
  • Thanks, it sounds to me like in that interview he is making the point that in our current best theories of physics (standard model of particle physics and general relativity) one can do physics perfectly well without making use of the concept of information, but at the end he seems to say he's open to the possibility that a future more fundamental/accurate theory might be fundamentally about information.
    – Hypnosifl
    Jun 4, 2020 at 1:00
  • @Hypnosifl: Yes.. It pains me that he wasn't asked specifically about loop quantum gravity as information, or the it-from-bit doctrine, but presented with just a woolly pop science framing.
    – CriglCragl
    Jun 15, 2020 at 0:57

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