Why is the universe comprehensible? by Ian Durham

Hi Ian,

Thank you for a wonderfully written essay. I enjoyed it and I am largely in agreement with your conclusion, particularly when you wrote ``The fact remains that in order to say we comprehend some element of the universe we must necessarily obtain some information about that element. But obtaining that information is a physical process that necessarily has a context which constrains the nature of that information; the very act of acquiring information shapes the information acquired''.

This is an excellent point and the principle of comprehensibility is certainly a reflection of the physical limitations handed down by the uncertainty principle. As you point out, if the context of the questions being asked don't agree because we choose two incompatiable measurements---say x and p---then their is a fundamental limit to the comprehension we can achieve.

You then moved onto the price about the price of comprehension which fundamentally boils down to errors arising due to incompatible measurements. As you point out, if I'm computing pi to 50 trillion decimal places using two different algorithms, then surely they will reach different conclusions if they are not identical.

The uncertainty principle is certainly the fundamental limit of your essay, as it it in contextuality. If you ask an incomprehensible question, then it requires an infinite amount of energy to extract all the information about a particular variable. That is, localising your particles position does requires that you infinitely squeeze along p.

I largely agree with you and your essay and wrote a very similar essay focusing on the limits of computation, although focused from the perspective of open systems and dissipation---the errors arising from incomprehensible questions if you like---titled noisy machines. I hope you get a chance to take a look!

Well done on the great essay! I really enjoyed it!

Cheers,

Michael

Dear Professor Ian Durham,

Thanks for replying and sharing your thoughts!

Well, the way I interpreted this is when posing questions and constraining the universe of answers, we make sure it corresponds well to certain underlying grammar and semantics; and thus physics gets anchored to logic and mathematics.

In other words, science is projection of our observation onto the canvas of formal systems, such as logic and mathematics; hence why I stated physics gets anchored to mathematics and logic rather than the other way around.

In many way your work resonates well with Wittgenstein's seminal work Tractatus Logico-Philosophicus where he emphasis the centrality of language in understanding the world.

Best Wishes,

Raiyan Reza

Dear Ian,

This is a well-written essay for a general science readership that explains and defends thought provoking ideas. In other words, a perfect fqxi contest essay. It was fun to read and I think you had fun writing it. I hope you do well.

You do blame the state of the Physics on observers in the Universe, but your statements would offend only people in that category. On the serious side, the mechanics of creating valuable questions is the most important skill needed in science.

Sincerely,

Jeff Schmitz

Hi Ian,

My essay "Why your Robot is just not that into you" is mathematically out of the running, but I would like your opinion (bad or good). Any comments would be helpful for the next contest.

Sincerely,

Jeff

Dear Ian,

"Why is the Universe so comprehensible?" A great topic to which you have written a most stimulating essay.

I think our world is comprehensible because humans are good at searching out and then explaining patterns. First in natural science, then in our own creation - mathematics. As our science progressed, some of the patterns, or our deductions about them became established as our principles or laws - especially where symmetry was involved.

I believe, like Einstein, that `comprehensibility' means a scientific understanding of the universe's functional composition. In my essay I cover how the 3 Un's have impinged on my thinking as I work towards my goal of 'Structural Physics'.

If a condition of comprehensibility is one of measurement, and as you quoted "Feynman once famously said, if something disagrees with experiment then it's wrong", then isn't defining the experiment and its measurement in a truth-conditional way extremely important. Some might argue that is where EPR experiments have come unstuck. Part of the price of comprehensibility is the way we design our experiments.

On another thought-line, you stated: "Markus Muller recently constructed a self-consistent theory in which an objective external world emerges from more fundamental observer states." Isn't this similar in some way to applying Susskind and 't Hooft's idea of a holographic black hole event horizon to the Universe through multiple observer states? After all, Muller thinks the link between entropy and information remains, possibly leading to a holographic principle.

Thanks for your essay as it has extended the boundaries of my thinking.

Lockie Cresswell

Dear Ian,

I am absolutely delighted by this essay. One of the things you touch on is the separability (for lack of a better word) of the universe. We can make sense of it because of how explanations remain "in their proper bounds".

One thing I'm curious about: are there examples in "normal" life where explanations go out of bounds? i.e., you write "While it is impossible to prove that the answer to the question "what color is my hair?" will never be "narrow" or "dog", the fact remains that it is highly unlikely." It is possible to come up with an example that (however unlikely) violates the Principle of Comprehensibility?

Yours,

Simon

(You can find some remarks on "mutual explainability" in my contribution this year, for which I'd love to have your thoughts--please feel free to drop me a line by e-mail or as you please, because I think there's a lot of philosophical literature for me to learn from.) https://fqxi.org/community/forum/topic/3492

Hi Ian,

I waited a while to read your essay as I thought, comprehensibility is a too incomprehensible expression in order to get something comprehensible out of it. I was wrong. It was a clear enjoyable read. A few questions however remained that I would like to ask and a few remarks I would like to make.

It seems to me, that you the context, under which a question can be comprehensive, must be classical. I completely agree, that the very meaning of a spin, implies the possibility to make an experiment along some direction and that we can know in which direction has been made (and share this information). This means that the directions must be somehow classically distinguishable. They can be constructed as coherent spin states. But could you imagine, that someone holds a superposition of two such 'classical' states as context and not being able to agree with you in which direction the spin measurement has been done? Or do you see limits in the applicability of the superposition principle?

I personally cannot really get some operation meaning from such a superposition, as normally the superposition is not an eigenstate of a generator of the group SU(2) representation except for the lowest non trivial representation 1/2. But then one of the main principles of the QM seem to have only limited applicability.

In a similar matter you seem to look for a reconciliation between the subjective view and an objective one. This seem to me is a problem brought to us mainly in QM and specifically by Wigner's friend type experiments. Does the stability of the universe also here play a role for the comprehensibility of the experiment?

The stability of the universe sounds for me extremely dramatic and I do not know what you exactly count as stable. I asked this last question, because in my essay, the condition for an experiment to be comprehensible (I call it definable or measurable in my essay), is to be unitary and symmetric. So if Wigner tries to measure his friend being in the superposition with the probe, he breaks unitarity and symmetry within the friends subsystem. So Wigner trying to make a incompatible measurement on his friend would be enough to destroy the stability of his friends lab experiment.

You actually do not answer the question of why the universe is comprehensible, but of under which conditions it is. I would be happy, if you would find the time to read and comment on my essay that has a similar topic. I ask under which physical condition physical concepts are definable.

Luca

Dear Ian,

Good essay, interesting view. I agree there "..exist problems that are undecidable for physical reasons" and "The universe has fundamental limits baked into it." but can we not reduce them to 'infinitessimals'? If you interact with a spinning sphere at the equator and I ask; 'Is it + or - rotation?' Can you tell me? But how CLOSE to the equator must we be get 50:50 certainty? Is that not, as I think you suggest, just a matter of experimental precision, so can be reduced!? Now that +/- decidability also INCREASES, by CosTheta Latitude, from 0 to 1 towards the poles.

So now consider your Stern-G Fig.1.; We know all light has ellipticity, as do all orbitals, so if we hypothesise polariser interactions can change ellipticity (major axis orientation) as well as polarity, then we can say the magnets divert the 'state' BOTH WAYS, but only ONE channel corresponds to major axis amplitude so can 'click'.

Now in THAT case, with some simple conditions (shared axis, and vector additions) we can surely reduce 'quantum uncertainty' to the physical limit you suggest!? I've found that a powerfully resolving hypothesis, as I discuss in my own essay, giving Bells inequalities physically, as he always suggested was possible.

We can then ask the truth value question; "is my hair blond?" and get answers of recursively reducing precision of HOW blonde!? So a 'reducing' not 'excluded' middle between Blonde and Brunette.

You struggled with that concept last year, perhaps even ran from it as some do. Now I think it should be more comprehensible from your own viewpoint. Do let me know.

Very best

Peter

Dear Ian,

which color of hair would a pre-colonial Bantu have assigned to Marilyn Monroe? And what about an alien from a planet orbiting Sirius ?

"The universe has fundamental limits baked into it." Isn't it rather so that these 'limits' are constitutive means for there being something at all - FOR US?

Heinz

Hello Ian, Neil Bates here. I am very impressed by the literary quality of your piece, as well as the broad interdisciplinary scope and variety of picking various conceptual metaphors and points to make. Certainly something worthy of publication in a semi-popular science education forum. I must agree that issues of language in science and even basic description of experience can't be brushed aside. Too often, authors take the material of their discussions as simple clear givens. This is so despite decades of wrangling over the philosophical problems of quantum mechanics and even the scientific method. It is important in issues of the peculiar "Renninger null measurement" where we presume a "wavefunction" must have rearranged because a detector that COULD have found a particle showed a negative result. And what about unreliable detectors? Can they have ontological significance?

I haven't seen much similar to your speculations about the effective relativity of calculation. Some would say "so what" because math is conceived as a perfect Platonic thing in itself, yet foundational mathematicians still argue over discovery versus construction, the viability of unmet counterfactuals, etc.

Also: If you or other readers might take at look at my own piece, addressing the issue of the strong correlations of entanglement and how neo-mechanistic models of quantum physics aren't enough - it could use some votes on this last day. Thank you.