
The Weakness of Anthropic Arguments - srl
https://ineffectivetheory.com/weakness-anthropic-arguments/
======
goodside
I feel like the challenge of explaining fundamental constants understates the
strength of anthropic reasoning. Most regions in space are empty voids — why
aren’t we in such a void right now? Being anywhere near the orbit of a star is
extremely unlikely a priori. Why are we on a planet with oceans teeming with
other life forms, instead of a barren rocky desert, which seems to be the norm
for planets in general? Why are we exactly on the _surface_ of that planet, as
opposed to being 1,000 kilometers up in the sky or down underground, swimming
in hot magma?

These are the questions where “Because those are the only conditions suitable
for your existence to happen” is so obviously correct the questions make you
roll your eyes. Applying the anthropic principle to fundamental constants is a
speculative extension that might be right or wrong, but there are plenty of
mundane coincidences that have no other answer.

~~~
tlb
Empty space is like the pencils lying on the ground in the article's analogy.
We can observe both habitable space and empty space, and we have a good theory
to explain why we don't find ourselves in empty space. With some effort we can
go to empty space and see what it's like.

But we can't observe parts of the multiverse with different fine structure
constants, which puts it in a different category of entities that Occam's
razor recommends not to multiply.

~~~
goodside
Agree completely, but a lack of direct observation isn’t the only evidence we
have, at least in principle. If you had an unimaginably powerful computer that
could run simulations to determine whether life could form for other values of
fundamental constants, the answer would say something about the plausibility
of an anthropic explanation for their values. If it turns out that any slight
adjustment makes life (of any form, however alien) impossible, anthropic
explanations are more likely. If it turns out that any choice of constants
produces _some_ form of life, anthropic explanations are less likely. We can’t
run this simulation, but we can make at least weak inferences about what parts
of the parameter space preclude life.

More speculatively, as we’ve gathered more observation, we’ve repeatedly found
a world consistent with the theory, “Things could be different; your local
conditions are unrepresentative; there was a de facto parameter sweep and
you’re in an odd corner of it.” Humans are in a very specific place with
respect to their surroundings on many, many scales. Admittedly, though, not on
the very largest scales we can observe. The cosmos does appear homogenous
eventually. Anthropic cosmology is tantamount to the claim that this
homogeneity isn’t the end of the story, and that on some “larger” scale (which
might not correspond literally to spatial position), the non-homogeneity
resumes and explains why our region is the way it is. If there were some a
priori theoretical reason to suppose that constants actually do vary, just so
slowly that they appear constant within any given Hubble volume, it would add
credence to the explanation that we’re just once again in an odd part of a
parameter sweep.

~~~
meheleventyone
Isn't the issue there verifying that our simulations of other values are
accurate?

For example within a certain range of values Newton's law of motion hold but
outside of that they don't. We can simulate outside of that range as if they
do but luckily can observe that those simulations don't hold experimentally.

~~~
tlb
Yes, it's hard to verify simulations. Not because we don't know what the
equations are, but that solving the equations with finite amounts of computing
requires a lot of clever approximations which are hard to verify except by
comparing with experiments, which we can only do for the laws of physics that
operate in our neighborhood of the multiverse.

The ultimate experiment would be to start simulating at the big bang with
slightly different parameters and see if intelligent life evolves on one of
the simulated planets after several billion years of simulated time. But we're
very far from such an experiment being feasible.

~~~
meheleventyone
The point is that we’ve worked out the equations based on what we observe from
our Universe. We don’t know and can’t demonstrate they necessarily hold for
other constants or Universe configurations. Just like Newton was correct with
his laws of motion for the range of values he had access too but subsequently
we know they don’t work for both much smaller scales and much larger scales.
And we have no way to verify that our equations do accurately model other
universes even if we could argue that they do. So no amount of fidelity of
simulation (and associated problems therein) necessarily demonstrate anything.

We shouldn’t confuse the map for the terrain in other words.

~~~
tlb
We may be talking about two different things. I'm talking about a multiverse
where different parts have different values for constants (like the fine
structure or gravitational constant) but the equations are the same. If you're
talking about a universe with structurally different equations implying
different conservation laws, then indeed we can't demonstrate anything about
it.

~~~
meheleventyone
But we don't know either way... and importantly don't (yet) have a means to
know.

Axioms aren't helpful in that regard.

------
AgentME
I think this post's assumption that intelligent life is inevitable is
unsupported. Just because lots of systems are Turing complete doesn't at all
imply that intelligent life or even life in general is likely to arise from a
random initial state. There's no support in the post for this jump in logic.

I think the solution to the Fermi paradox is that intelligent life is just
spectacularly unlikely, and that we're the only intelligent life in the
observable universe. I think most people reason that we're probably not that
special, that our conditions aren't too rare, and that the likelihood of
intelligent life given those conditions must be somewhat good, but I don't
think any of this reasoning is valid given the anthropic principle. I think
the fact that we find ourselves in a world where we're alone is evidence for
the sheer unlikelihood of life.

If there were many values of the fine structure constant that could create a
universe with any life at all, then I would guess that across that range of
values, there would be more variation where some values would create a
universe with rare lonely life and some values would create a universe where
life was more plentiful. In that case, we would be more likely to find
ourselves in a universe where life was more plentiful. But if there were a
tighter range of possible constant values that create a universe with any life
at all, then I would expect less variation with only universes with rare
lonely life. Given that we find ourselves in a universe with rare lonely life,
that seems like evidence that there isn't much room for variation in the
constants while staying life-supporting.

~~~
TillE
It's somewhat reasonable to assume that we're the only intelligent life in our
corner of the galaxy (the practical reach of an artificial radio signal), but
the observable universe is a really, really big place.

~~~
AgentME
It's been estimated that self-replicating Von Neumann probes could populate
our galaxy in 10 million years. I haven't seen an estimate about them
populating multiple galaxies, but I assume many could be hit within some
multiple of that, and the growth would be exponential. Even if most
intelligent life generally doesn't decide to make self-replicating probes, it
only takes one civilization in the history of the (observable) universe to do
it to make a huge effect.

It's possible that life is just likely enough that none of them have yet
chosen to or have been alive long enough to create self-replicating probes,
but I don't think it's correct to assume that the likelihood value for life
would be on the extreme upper end of the range that's compatible with our
observations.

------
ggambetta
> In this universe, where α ≈ 0.007297352569, you’re reading an article about
> the anthropic principle; in the universe where α ≈ 0.007297352569, at the
> very least, it’s reasonable to guess that you would not be. (Good news: in
> that universe, you’re a billionaire playboy philanthropist!)

Both values of α look identical to me, but the text implies that they're
subtly different - is this a typo in the article, or am I missing something?

~~~
couchand
I read this as putting all the weight on the wavy approximate equals; the
alternate universe described is incredibly similar to, but not quite the same
as, ours.

~~~
leephillips
I’m sure he must have meant to change the last digit, but something went
wrong. We exist because of a typo!

~~~
TheSpiceIsLife
Thereby exposing God as nothing more than an average _copy editor_.

------
njarboe
The Anthropic principle idea that this universe's physical properties can't
vary much and produce carbon/hydrogen/oxygen (CHO) based life on the surface
of planets is probably not correct and was just popularized many decades ago
when the understanding of nuclear physics was not as complete as it is now.
The possible paths to a CHO universe with acceptable planet surface conditions
were not well explored.

From the linked article: "Suppose the fine structure constant were in fact 10%
different — enough to prevent stellar fusion from producing carbon."

This is an old idea and is probably false (I am not an astro/nuclear
physicist) but the author of this in-depth paper is[1]. Fred Adams is at the
Physics and Astronomy departments at the University of Michigan and in this
2019 paper[1], with over 500 references, states the fine structure constant
can vary by 4 decades/orders of magnitude (decade=log10(max value/min value)).
See table two on page 140 for that range and ranges of some other fundamental
values. The most constrained value ranges still vary by an order of magnitude
(down quark mass and the up-down quark mass difference).

[1][https://arxiv.org/pdf/1902.03928.pdf](https://arxiv.org/pdf/1902.03928.pdf)

------
squibbles
I find the argument against anthropic arguments to be weak.

* The terms _life_ and _intelligence_ lack formal definitions.

* The predicate _why_ lacks a formal definition.

* The argument does not address the maximum number of possible configurations of the universe, which dilutes any quantitative arguments. Most importantly, the cardinality of the maximum number of possible configurations is not addressed. For example, the possibility of an aleph number [0] was not addressed.

* The argument does not address qualitatively different structures of the universe, such as universes with discontinuous lengths or types of affine spaces [1] where measurement as we understand it does not exist.

The list of concerns above is not exhaustive, and I don't think addressing
them individually will necessarily salvage the argument. While stronger
arguments for or against the anthropic principle are possible, I think they
deserve much more rigor.

[0]
[https://en.wikipedia.org/wiki/Aleph_number](https://en.wikipedia.org/wiki/Aleph_number)

[1]
[https://en.wikipedia.org/wiki/Affine_space](https://en.wikipedia.org/wiki/Affine_space)

------
Veedrac
The key most people miss about the anthropic principle, and that seems to be
the confusion here, is that when you're filtering out false hypotheses (those
inconsistent with the observed facts), all remaining consistent explanations
increase in probability equally. This means, for example, if you want to
explain how Derren Brown won the lottery, the probability that he cheated
raises in line with the probability that he just got lucky, which is
exponentially low, hence it is almost certain he cheated.

The base probability is, as always, based on some form of Solomonoff
induction, which is invariant to ‘scale’, hence why we can explain away
seemingly-arbitrarily low probability events (α≈0.007297352569) by talking
about universes that contain a continuum of different α. In the lottery
example, the hypothesis ‘lots of people tried’ is simple, even if the
probability of each individual winning the lottery is low.

You might ask instead, but what's the probability that _that specific person_
won the lottery? Surely that is exponentially less likely? Yes, indeed, but
unlike the Derren Brown case, where P(Derren Brown cheats the lottery) is
fairly high prior to him winning the lottery given the public attempt, P(that
random guy cheats the lottery) is very low, as most people don't cheat the
lottery.

Thinking about alternative observers and question-asking is a distraction.
_Other_ people asking _other_ questions are not you, so they are not
compatible with your observations.

------
roenxi
If we start with the theory that universal constants are random (big if) then
the question he is pushing towards doesn't make any sense. Why does a random
number take on a specific value? That is a question for philosophers, not
physicists. If we were observing a truly random number then it doesn't mean
anything for it to be a specific value.

It is a fair point if nobody has proven (or indeed, can prove) that something
in physics is a random number. But alas that does not mean the theory is weak.
It is perfectly consistent with the evidence, and mathematically satisfying.

It would be quite exciting if someone can find a reason why we observe
specific values and rule out the random number idea. But at some point we know
we'll run up against the impossible questions of "why does anything exist at
all?", "is it possible for something to not exist?" and "what separates
existence from non-existence?". We can't expect to find causal answers for
everything.

------
metalliqaz
But I thought the purpose of the Anthropic principle was not to answer, "why
is this thing?" but rather, "why is this thing so perfect for us?". Those are
very different questions.

~~~
throwaway_pdp09
As our n=1, how can you claim that it is indeed the best of all possibilities
("so perfect")?

~~~
harshitaneja
We need a large number of samples when we lack sufficient understanding of the
system in study. But if we assume our current knowledge of physics and biology
are good enough then we should be able to find the best(whatever definitions
is used) without needing multiple samples. We use multiple samples to create a
model but if a model exists then non-contradicting samples add nothing.
Although we could have a large discussion about bayesian epistemology
regarding my last statement.

~~~
throwaway_pdp09
> But if we assume our current knowledge of physics and biology are good
> enough

That's a bloody big _if_ , but let us let it ride for now

> we should be able to find the best(whatever definitions is used)

Agreed it hinges on that, assuming the preceding _if_ is accepted. What 'best'
do you nominate? I have no idea what it might be.

~~~
harshitaneja
It is a big if. My choice of words was very deliberate as I didn't wish to
convey that our knowledge is sufficient. But the question here doesn't hinge
on real knowledge(our ability to ever gain it is in itself a huge question)
but rather on belief in possessing the said knowledge. Otherwise every real
world calculation of probability is meaningless as physical systems can't have
proofs but rather more and more tested models acting as the prior in our
calculations.

I don't nominate any best. I don't have an idea either. I merely used a word
used by a parent. Best could be minima, maxima or any other criteria of the
function they choose to refer here.

My point is if you have a belief that your model is good enough, you don't
need a large number of trials to calculate a probability on whatever
characteristic you choose.

The accuracy of this result is a question but the question would remain
similar to the scenario where you calculate the probability from a larger
number of trials.

------
m4r35n357
Isn't this just a form of "survivor bias"? I don't get why anthropic arguments
are considered "weak".

The article seems to just be complaining that anthropic arguments cannot
explain the precise _value_ of the fine structure constant. Well, nor can
Occam's Razor, but we don't seem to have a problem quoting that!

~~~
rbanffy
My understanding is that they are an attempt to explain away something that
may or may not be random.

We wouldn't be debating it if the universe were substantially different, but
that doesn't explain why the universe we observe is the way it is.

~~~
m4r35n357
OK fair enough, to me the opposition to the weak AP just seems to be people
"unhappy" that a physical constant should need to be that precise.

In other words, for some reason they expect the universe to be more
"understandable" or "sensible" than this . . .

Of course the strong AP is ludicrous in the extreme ;)

~~~
XorNot
It wraps up a concern that there are these seemingly random constants in our
models that don't seem to be a product of our measurement system.

There's no number system you can invent where the fundamental constants turn
into simple integers or have obvious ratios.

So why do they have those values? What gave them those values? The anthropic
principle is disliked because it rejects further inquiry and progress.

~~~
greatquux
I don't think we can reject it though. We may not / shouldn't "like" it, and
we can sort of shove it to the background and try to come up with other
explanations or theories that are more explanatory, but we do have to
acknowledge that at least the weak form does make a kind of sense and we can't
ignore it.

~~~
rbanffy
AP can't really make sense because it doesn't explain anything. We know a
universe with our values works because we are observing one. Any set of values
that "work" in this sense will have someone to make the same observation.

Unfortunately, that doesn't explain how these values are generated. _That_ is
the important question.

------
maroonblazer
Sean Carroll (theoretical physicist) and Nick Bostrom (philosopher with a very
technical background) discuss Anthropic arguments on Sean's Mindscape podcast
a few weeks ago.

[https://www.youtube.com/watch?v=EffcY6tnbcA](https://www.youtube.com/watch?v=EffcY6tnbcA)

------
flerchin
It seems to be the final answer in a game of "why"? with a 2 year old.

~~~
falseprofit
I think that game should end at the question of
[https://en.wikipedia.org/wiki/Why_there_is_anything_at_all](https://en.wikipedia.org/wiki/Why_there_is_anything_at_all).

I don't actually think the anthropic principle is capable of tackling that
one.

~~~
Izkata
"Because nothingness was bored."

( Original intention of the backstory of
[https://andromeda.fandom.com/wiki/Trance_Gemini](https://andromeda.fandom.com/wiki/Trance_Gemini)
)

(Yeah, not quite anthropic principle, but definitely popped into my mind as
something to give a 2-year-old)

~~~
falseprofit
My attempt at an answer would be that emptiness/nothingness is just a made-up
concept. Not a good answer, I know, but idk what else to think.

------
mensetmanusman
If intelligence is ‘extremely resilient’ then we will find it everywhere in
our universe.

If you use the cellular automata analogy that is being alluded to,
‘intelligence’ is being essentially equated to some limit of ‘complexity’

This is all very hand-wavey so it doesn’t appear to add much to the
discussion?

~~~
goatlover
Yeah, there needs to be evidence backing up a claim to extreme resilience.
Invoking scifi scenarios and Turing completeness does not count. One can
easily counter with the Fermi Paradox and only one species on Earth asking
anthropic questions.

------
DDaa
Anthropic principle has been used by too many people to meaning too many
different ideas. It really should just refer to the mere tautology that "I can
only find myself exist, and the world in a state compatible with my
existence". That is a perspective specific statement. It answers questions
formulated from my/our first-person perspective: "why do I find the
fundamental constants compatible with my existence?". However, it does not
apply to questions formulated objectively (i.e. when it requires a perspective
invariant response), for example "why are the fundamental constants have these
values?". That question calls for an impartial causal model or scientific
answer. Anthropic principle simply isn't it.

That doesn't mean AP is wrong, it is a tautology, correct by definition.
Neither is AP useless. It is the correct counter to teleological arguments
such as fine-tuning. However, treating it as a scientific explanation is not
correct.

That being said, that confusion is totally understandable. The current state
of anthropic reasoning is quite messy. There are contending theories on many
related paradoxes. The sleeping beauty problem, the doomsday argument, the
fine-tuned universe, the simulation argument, etc. Like before, I find these
paradoxes are caused by ignoring the role of perspectives as well. I explained
my solution to the related debate on my website
[https://www.sleepingbeautyproblem.com](https://www.sleepingbeautyproblem.com)
if anyone is interested.

------
laszlokorte
`Why is this question encoded as string of 385 characters and why is there a
set of 385 character long strings? I mean there could be just a set of strings
of length 95 and the question could instead ask "why is this question of
exactly 95 letters long and why is there a set of 95 char long strings?" but
still this specific question is asking why it is 385 chars long, why is that
so?`

~~~
squibbles
One answer to "Why is this question..." is because we have defined it so. And
why did we define it so? One could make an argument that notions of sets,
counting, length, and so on are anthropomorphisms -- we project our bodies
onto the universe around us so we can reason about the environment using our
specialized brains. (Human brains are specialized to operate in the context of
our bodies.) In fact, the Whorf hypothesis [0][1][2] addressed this subject in
the context of linguistics.

[0]
[https://en.wikipedia.org/wiki/Linguistic_relativity](https://en.wikipedia.org/wiki/Linguistic_relativity)

[1]
[https://plato.stanford.edu/entries/linguistics/#SoCalSapWhoH...](https://plato.stanford.edu/entries/linguistics/#SoCalSapWhoHyp)

[2]
[https://www.sciencedirect.com/science/article/pii/B008043076...](https://www.sciencedirect.com/science/article/pii/B0080430767030424)
,
[https://doi.org/10.1016/B0-08-043076-7/03042-4](https://doi.org/10.1016/B0-08-043076-7/03042-4)

------
flatfilefan
Were you guys ever curious as to what the word “anthrop” means exactly?

Here’s an interesting explanation from Socrates:” Socrates I will tell you.
The name “man” (ἄνθρωπος) indicates that the other animals do not examine, or
consider, or look up at (ἀναθρεῖ) any of the things that they see, but man has
no sooner seen—that is, ὄπωπε—than he looks up at and considers that which he
has seen. Therefore of all the animals man alone is rightly called man
(ἄνθρωπος), because he looks up at (ἀναθρεῖ) what he has seen (ὄπωπε).”

[http://perseus.uchicago.edu/perseus-
cgi/citequery3.pl?dbname...](http://perseus.uchicago.edu/perseus-
cgi/citequery3.pl?dbname=GreekFeb2011&getid=1&query=Pl.%20Cra.%20399c)

And yet the English “man”, Spanish “hombre”, Russian Мужик mean the same yet
different thing, namely a (working) hand. As in “how many hands do you have in
your factory?”

------
jankotek
》This would prevent carbon-based life from existing, sure; but would it
prevent intelligent life from existing?

We are yet to find another primitive carbon based life form. Anthropic
principle works just fine with Occam's razor.

------
sullyj3
Max Tegmark goes into detail on the potential pitfalls of anthropic arguments
in "Our Mathematical Universe". Very interesting book.

------
tunesmith
This is a little new to me, but as described, isn't it like a form of a proof
by contradiction?

I mean, it doesn't have to bring in "we wouldn't be here" questions of
survival, it seems to be just of the form of...

(1) Question whether A is true. (2) If A were not true, then it would
necessitate that B is true. (3) B is clearly impossible. (4) Therefore... A
must be true.

~~~
tuatoru
Proof by contradiction only applies to mathematical/logical theorems, which
are also known as tautologies.

It's useless for statements about the physical universe.

Edit: IIRC the form is

    
    
        !(!A || B) && !B
    

which reduces as

    
    
        (A || !B) && !B
        (A && !B) && (!B && !B)
        A && !B && !B
    

Given B == false

    
    
        A && true && true
    
        A

------
tuatoru
The article gives a crude statement of the principle as

> The universe is the way it is because if it weren’t, we wouldn’t be here to
> discuss the issue.

That can't be right. That statement says we are here _as a consequence_ of the
way the universe is. It says _nothing_ about causes (of the universe being the
way it is).

What's a better statement of the principle?

------
webmaven
Perhaps I am missing something, but doesn't the presumed "existential
robustness" of intelligent life mean that any affected anthropic principle
arguments just devolve to the "well it had to take _some_ value" answer
mentioned at the very beginning?

------
dcanelhas
Why is intelligent life held as such an inevitable outcome these scenarios?
Could it not be the case that we look around and see billions of species (just
on Earth) that are no smarter than ants (i.e. pencils lying around) and draw
the conclusion that it was just luck instead?

------
lordnacho
The thing about the fine structure constant always bothered me. If it were
slightly different, our universe would be very different. But how do we
quantify how different is different enough to warrant investigation? How do we
know what the range of such a number could be?

~~~
at_a_remove
Ah, well, about a four percent change and you no longer can produce carbon
during regular fusion. You need atoms capable of making at least three bonds
to produce structure more complex than a chain. Carbon can do four, is lovely,
otherwise you would have to make do with boron and nitrogen.

Crank the value up to .1 and you get no fusion at all. This one is super-
interesting, because no fusion means no photonic pressure keeping silly large
accumulations of gases _up_ and so you will crank your way to neutron stars
and black holes much faster, as well as resulting in a universe whose only
light is the remaining cosmic background radiation. No more supernovae
creating shockwaves and the like.

In the other direction and you have a different problem -- molecules won't
molecule and you will just have a bunch of disconnected atoms incapable of
covalent bonds.

~~~
lordnacho
Yes but how do we know what the numbers could have been? It's not like we have
a generating theory that says it had to be between a and b, and thus it being
x is really unlikely.

~~~
at_a_remove
Ah, okay, that's a different question.

Aside from common sense ("this being negative would be self-contradicting")
for a given number and sets of inter-relations, that's out of my wheelhouse. I
very dimly recollect some work on allowable sets of constants somewhere in the
nineties, something to do with superstrings, but that was never a huge
interest of mine. I will admit that such a generating theory may exist and I
am just unaware of it.

In some sense, each constant represents a bit of embarrassment to physics.
Having this rather large set of adjustable parameters calls to mind the von
Neumann quote "With four parameters I can fit an elephant, and with five I can
make him wiggle his trunk."

Why _this_ seemingly arbitrary number? Can we take multiple constants and find
some smaller set from which they are derived? Can I make a constant emerge
from a physical law, devoid of measurement?

------
mensetmanusman
Are we comfortable admitting that this can never actually be answered with the
scientific method?

This puts all realms of the discussion in the metaphysical, which is fine, but
it should be noted :)

~~~
srl
It's perfectly fair to complain that these discussions are untestable, at the
very least, but unfortunately they're inescapable. We need some heuristic for
evaluating which anomalies/patterns are likely to be hints of "new physics"
(and are thus worth investing resources in exploring further), and which ones
are just coincidence or otherwise not worth investigating.

Anthropic arguments seem to provide a reason to be uninterested in a large
class of apparent surprises. Should we invest in investigating those
surprises, or not? The discussion may be metaphysical, but the decision has
real-world consequences.

~~~
mensetmanusman
Thanks for the comment.

I am by no means trying to downplay metaphysical discussions, most lived human
experience is in that realm (“what should I wear/eat/do/etc.”), so one could
argue it is more important than many scientific/engineering endeavors looking
to find new ways to serve advertisements :)

I love the discussion of complexity and automata, and I struggle to think how
our limited minds will ever work around the problem of unbounded complexity...

------
golemotron
Honestly, I think this article about anthropic arguments is weak. Expressing
discomfort with an argument isn't an argument.

------
alexpetralia
Does anyone know if panpsychism is an anthropic argument?

~~~
falseprofit
If anything, it uses Occam's razor, reducing {conscious matter, unconscious
matter} to {conscious matter}.

