Comment by ValentinA23 | Hacker News Reader

Comment by ValentinA23 | Hacker News Reader

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The anthropic principle in its weak form isn't really a hypothesis - it's more of a methodological principle that warns us against unnecessary theories. This is best illustrated by the historical debate between Dirac and Dicke (who came up with this idea) about cosmic coincidences.

In 1937, Dirac noticed striking numerical relationships between fundamental physical constants and the age of the universe [1]. He proposed these couldn't be coincidental and suggested fundamental constants must vary with cosmic time. But Dicke (1961) showed that some of these "coincidences" weren't so mysterious: they were necessary conditions for our existence as observers [2]. The universe had to be old enough for heavy elements to form in stars, but not so old that all stars burned out. These constraints naturally explain some of the numerical relationships Dirac found, without requiring varying constants.

However, Dicke's argument has limits: it only works for coincidences necessary for intelligent life. It can't explain away "gratuitous coincidences" - numerical relationships that aren't required for our existence. This is particularly relevant because Dirac's work was actually part of a longer tradition - going back to Weyl in 1919 [1] - of physicists finding peculiar numerical relationships between physical constants.

While the article discusses coincidences that make our existence possible, we need to consider how to explain the other ones. Is it even feasible ? Let me give it a try.

If physical constants were "set" randomly, with their observability conditioned only by whether they allow intelligent life, we should expect to find both types of coincidences in our universe: the necessary ones that enable our existence, and gratuitous ones that just happened to come along for the ride in our universe's "roll of the dice".

This leads to a disturbing conclusion: for laws of physics to be discoverable by observers in a universe without a creator, they must contain misleading elements as a by-product of what allowed these observers to emerge. The universe seems to impose a double-bind on its observers - the very conditions that make it observable must also make it deceptive.

[1] https://en.wikipedia.org/wiki/Dirac_large_numbers_hypothesis https://en.wikipedia.org/wiki/Anthropic_principle [2] https://en.wikipedia.org/wiki/Anthropic_principle#Anthropic_...

This is only loosely related but I thought you might be interested in a new paper, just described[1] by Sabine Hossenfelder.

They started with the assumption of a multiverse, and said that we're most likely to find ourselves in a universe that has physical constants allowing for the most observers. They checked such a constant, and found that the constant is nowhere near the ideal; if it had been different, there would be a lot more planet-bearing stars in our universe. They claimed this as evidence that the other universes don't exist.

[1] https://www.youtube.com/watch?v=IXzV7zdl4oU

Here's a counterargument.

Let's say there are two possible coincidences, A and B, each with an independent one-in-a-million chance. Coincidence A is necessary for life to emerge, but B is irrelevant.

Now let's say there are a trillion universes, with random settings. Only one in a million universes have coincidence A, but those are all the universes with observers. All the observers see coincidence A.

Out of those million universes, we can expect to see only one universe with coincidence B. The vast majority of observers will only see the coincidence that allowed them to exist.

But how can you determine that you're not one in a million?

You can't, not for sure. But this does mean that we shouldn't expect to find gratuitous coincidences. Most likely, the apparent coincidences we observe in physics and cosmology will either be necessary, due to physical relationships we don't understand yet, or will be explainable by the anthropic principle.

Would being one in a million itself be a coincidence though, one which we couldn't differentiate from coincidences explainable by the anthropic principle? "Most likely" doesn't satisfy me.

It's easy to form conjectures, but there is a deep metaphysical problem when it comes to satisfactorily modeling a system from the inside. It's turtles all the way down [0]. Unless our universe is embedded within another system, and its configuration at least partially mirrors the configuration of the system it is embedded within [1], and this is recoverable, then we really just can't make many absolute claims about the nature of our universe's particular configuration.

[0] And the only way out is by solving the deepest metaphysical problems which physics has not been able to touch, such as, "Why is there anything at all?"

[1] An example might be the conservation of energy, or stationary action. If such principles were to hold even within a system our universe might be embedded in, we could start to narrow down a few things and maybe uncover some suprauniversal inevitabilities. The challenge is proving that without observing the universe from the vantage point of a host system, which would really mean proving the inevitability of such principles in any system of sufficient complexity.

Anthropic principle explains only coincidences necessary for existence of life. If a coincidence isn't necessary for life, then it's not explainable by anthropic principle.

Physics isn't unable to touch the problem "Why is there anything at all?", it only doesn't touch it because the problem was declared to be useless to think about, and you obviously can't touch it without thinking. The usual reason is that the thing kept existing since previous time.

Not quite. It was declared useless to think about precisely because physics can't answer the most fundamental question of "Why". Richard Feynman went off on an interviewer for asking "Why are they doing that?" (regarding magnetic attraction/repulsion) precisely for this reason. [0]

He considers it a waste of time to consider, because you fundamentally can't make meaningful progress on the problem with our current tools and understanding, and it's possible that no amount of tools or understanding can reach the bottom-most turtle. There are some things we may simply never know.

https://www.youtube.com/watch?v=Q1lL-hXO27Q

That you can't make progress is not a fact, but an opinion. But it's a fact that you won't make progress if you don't try to solve problems.

As another example, Lee Smolin disagrees with anthropic principle, because he believes anthropic principle doesn't allow to study such fundamental problems. At least he thinks solving these fundamental problems is science's business.

I agree that it's worth pursuing, but it turns into a metaphysical journey, and metaphysics is a branch of philosophy, not physics. We have to establish that it's even possible to answer these questions.

>Physics isn't unable to touch the problem "Why is there anything at all?"

>Not quite. It was declared useless to think about precisely because physics can't answer the most fundamental question of "Why". Richard Feynman went off on an interviewer for asking "Why are they doing that?"

In Chinese, Korean or Japanese, "how" and "why" are the same word. A "why" after all, always decomposes into a "there is" (fields, particles, properties such as mass) and a "how" (the associated laws). Physics is restricted to the latter but hasn't been able to find a definitive frontier between the two. A "there is" often decomposes into another "how" and another "there is" after progress is made. Example: mass and the higgs field.

>We have to establish that it's even possible to answer these questions.

We won't know until we try. Like Poincaré conjecture was pending for a century.

My claim is just that if we see something that seems like an unlikely coincidence, we should look for explanations. Either there's some underlying reason that it isn't a coincidence after all, or there's a reason that no observers would be possible if it were otherwise.

It's possible that occasionally, we'll waste our time looking for explanations of things that really are coincidences. But since this will be rare, it's worth looking for explanations anyway.

So false coincidences or false gratuity (+ the rare coincidences allowed by the probabilities of non-correlated variables).

There seems to be a contradiction in terms in my approach: how could I conceive of gratuitous coincidences that are outside of the causal network necessary for life to emerge and at the same time expect they are not entirely independent from necessary coincidences ?

Both necessary and superfluous coincidences could be manifestations of "structural coherence" and correlate to the degree of "order" or "complexity" of the universe. I'm unsure about my choice of words (knowing that there are precise ways to measure those), but maybe what I'm trying to grasp at is that emergence of observers is a hard problem, as shown by the very small margins the fundamental constants need to sit within for this to happen. Our existence isn't attributable directly to the singular values they take, but to the expressivity they allow, carbon chemistry being an example of that.

Maybe the laws of physics and fundamental constants operate like a sophisticated construction system. Like Lego, they offer increased degrees of freedom and expressive potential, but this very complexity comes with the cost of enabling marginally legal or "quasi-valid" configurations. A high level of compositionality inherently generates possibilities beyond strict necessity—introducing both meaningful structures and potential anomalies.

We could almost put this to test by measuring how easy it is to find non-sensical quasi-equations in the laws of physics, comparing our set of fundamental constant values with randomly generated ones. I guess distinguishing false coincidences and false gratuity would constitute the wall preventing us from doing so.

Coincidences are possible, the question is what conditional probability you expect them to happen with.

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