
Shut up and calculate (2007) - nikolaypavlov
http://arxiv.org/abs/0709.4024
======
Analemma_
This is known as the instrumentalist approach to quantum mechanics, where we
deliberately avoid thinking about the philosophical interpretations of things
like the wavefunction, and only focus on the results of experiments. The
thinking being, the observables don't change regardless of whether you pick
MWI or pilot wave or the Copenhagen interpretation, so what does it matter?
(The actual phrase "shut up and calculate" is older than this paper; I think
David Mermin coined it.)

This approach rubs some people the wrong way, either because it's seen as a
failure of imagination on the part of physicists to look at the bigger
questions, or because it drifts close to the discredited logical positivism of
the mid-20th century. Those are valid complaints, but I think it can also be
seen as humility on the part of physicists, and an understanding that this is
outside their field of expertise. "Science" is a fundamentally empirical
exercise; if you're doing thinking without empiricism, it might still be
valuable thinking, but it isn't science. "Shut up and calculate" is shorthand
for, "Because these questions are not empirical, our tools and methods we have
as scientists are not capable of addressing them." It's acknowledging that
their powers are limited.

(I do think it would be nice if more physicists thought about it anyway,
because in their abscence the void has been filled with woo by a bunch of New
Age cranks, but that's not a moral obligation on their part)

~~~
n4r9
It's worth noting that Tegmark is advocating a particular approach to the
entirety of physics, not simply quantum mechanics. Taken to an extreme, a
further criticism of instrumentalism (due to Alan Sokal) is that the concept
of "dinosaur" becomes nothing more than a fanciful way for paleontologists to
come up with predictions about which fossils they will discover next.

I'm not sure I agree with you that "instrumentalism" is an adequate
description of the position of Tegmark outlines. Instead of neglecting to
assign an ontological status to anything, Tegmark appears to be assigning an
ontological status to the mathematical structures themselves.

~~~
danbruc
_[...] Tegmark appears to be assigning an ontological status to the
mathematical structures themselves._

Which appears to me similar to rejecting the idea of an universe that just
somehow came into existence or existed forever and introducing a god as the
source of the universe but still leaving you behind with the same questions as
before but now attached to the god instead of the universe.

And I personally don't really buy into the idea of mathematical structures
existing independent of humans or the universe or whatnot anyway. Humans bring
mathematical structures into existence, they postulate the axioms and explore
the consequences. That pieces of the universe are isomorphic to this or that
mathematical structure and therefore show similar properties and behaviors is
either accidentally or because a mathematical structure was explicitly
designed to mimic certain aspects of the universe, at least as far as I am
concerned.

~~~
poelzi
The only way to get out of this mess is self organization. Without a self
governing process that causes atom crystallization you will always end up with
some problem of beginning and end. Then the hole big bang theory is also
counter factual:
[http://www.cosmology.info/newsletter/2014.05.pdf](http://www.cosmology.info/newsletter/2014.05.pdf)

The BSM-SG model gives a very logical explanation how galaxies come to be and
the high order matter we can measure (proton/neutrons/electrons/positrons).

It does not give you an answer tho, where the 2 types of fundamental particles
come from, but their pure existence in mass quantities is enough for a galaxy
to be born, or in our case, many many galaxies.

------
n4r9
I agree that most physicists believe that an external reality exists.

I agree that physical theories aim to describe how it works.

But I disagree that it follows that our physical reality has a mathematical
structure. My objections are:

\- There is no compelling reason to think that "purely abstract" mathematics
any less anthropocentric than human language;

\- Even if mathematics transcends humanity, there is no compelling reason to
think that there is a single overarching mathematical structure of the
universe, despite being able to predict the outcomes of our interactions to
greater and greater accuracy as our physical theories develop.

It may be that Tegmark addresses these points in his "full strength" version,
but given the way he glosses over these hidden assumptions in this paper, I'm
not inclined to dig in and find out.

~~~
kazinator
Tegmark believes (pardon me if I have this wrong) that all conceivable
realities exist that can be described by equations, not only this reality. The
reality we have access to is the one in whose equations we are ourselves
locked up, so to speak.

I'm basically with Tegmark. For one thing, what has physics ever come up with
but equations, and improved equations to replace those, and so on? Everything
so far has been math.

So, going forward, either everything in physics will always be rooted in math,
or else some "non-math stuff" has to be discovered. (The very idea of "non
math stuff" being at the root of reality seems absurd.) What kind of thing
would that be? I think if we discover the ultimate equations then that's all
there will be: those equations, and mysterious constants embedded in them that
_just are_. The only explanation for those constants will be the anthropic
principle: if those constants were different, we wouldn't be here to
contemplate why they are, and in some other universe there are beings
completely different from us also wondering why their constants and equations
are they way they are.)

~~~
effie
> For one thing, what has physics ever come up with but equations, and
> improved equations to replace those, and so on?

Observations of nature and rational explanation of those in terms of old but
also new concepts. Equations are just one of technical artifacts to help us
think in a precise way. If we had computers sooner, there might have been
physics without differential equations.

~~~
kazinator
What observations are made in physics experiments which don't end up expressed
as a cluster of floating-point numbers?

~~~
n4r9
I think the previous comment was getting at concepts like "the laws of physics
are the same in all inertial reference frames". It doesn't directly refer to
any mathematics, although of course it can only be tested via the quantitative
predictions that follow from it.

~~~
kazinator
I understand the statement "the laws of physics are the same in all inertial
reference frames" as referring to correspondences and invariances among some
math under a coordinate transformation.

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tmerr
Regardless of what you call the universe, we already know 1. Everything we
know about it comes from sensory input, and 2. That sensory input's production
can be modeled mathematically. But it's hard for me to make sense of what
author really means by the claim "the universe _is_ math". He claims after
pulling away notation math is "A set of abstract entities with relations
between them". Great! But then again... any idea I can conceive of can be said
to be abstract entities with relations between them. That's an awfully vague
definition. Then it's as if he fills in the void with baggage from his
subjective understanding of mathematical structures (object movement is like 4
dimensional spaghetti). It's an interesting read but it seems like he just
wants his idea of the universe to be more literal than it is.

~~~
animefan
I disagree with 1 and 2, in the sense that i believe that sensory input has no
fundamental ontological role, and is merely how we biological humans bootstrap
our knowledge of macroscopic objects.

The real dilemma of quantum theory is how to reconcile this macroscopic world
with the world described by quantum theory. Personally I don't think many
worlds approaches make sense because they don't have an adequate description
of probability.

------
ambicapter
How does this square with Gödel's Incompleteness Theorem
([https://en.wikipedia.org/wiki/Gödel%27s_incompleteness_theor...](https://en.wikipedia.org/wiki/Gödel%27s_incompleteness_theorems))?

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PaulHoule
In your gut you know he's a nut...

[http://arxiv.org/find/physics/1/au:+Tegmark_M/0/1/0/all/0/1](http://arxiv.org/find/physics/1/au:+Tegmark_M/0/1/0/all/0/1)

~~~
danbruc
[https://en.wikipedia.org/wiki/Max_Tegmark](https://en.wikipedia.org/wiki/Max_Tegmark)

~~~
JadeNB
I think that there are respected scientists who know all the facts in that
article and still consider him a nut. (I say I _think_ because most respected
scientists are too polite, or politic, to say so directly, but it's the
impression that I've got in reading discussions of him.)

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poelzi
I'm into the BSM-SG model and this approach, is the same as we have now and it
failed. Using mathematical logic in quantum mechanics was one of the larger
mistakes we did...

reality is exactly the opposite, everything has a form, mass, movement,...

------
j-dr
I find it ironic that the title of this article is 'Shut up and Calculate',
seeing as he proposes no way to calculate the things that he proposes would
qualify his theory as falsifiable.

