# Bohmian Rhapsody

Is this the real world? Is this just fantasy?
Heisenberg’s theory is divorced from reality
Open your eyes, look into to the quantum sea

I’m just a boson, who needs locality
Because my $\Psi$ tells me where to go, pushing me to and fro
Any way my path goes, it’s all really hap’ning to me, to me

Quantum—what a bogeyman
Find a theory that embeds
Quantum—one that still retains
A truth not just in someone’s reference frame
Quantum—($\mu$) I can’t model spin but why
Should spin be that important in the long run
Baryon, Baryon, ’cause it’s all really matter

It’s been a hundred years
Since billiard balls and springs
Got replaced by stranger things
Goodbye, classicality, you’ve got to go
Got to leave it all behind and face the truth:
Quantum—($\mu$) I don’t want to roll the die
Sometimes I wish Born’s rule weren’t true at all

I see a little silhouetto of a man
Bohm-deBroglie, Bohm-deBroglie, will you tell me your theory?
Wavefunction and $\nabla \phi$, your equations guiding me
Albert Einstein, Albert Einstein, Albert Einstein, Albert Einsein
Albert Einstein, Schrödinger, von Neuman, Bohr
I’m just a boson, subject to uncertainty
He’s just a boson, restored in ontology
Spare him a life of epistemology

Who needs reality, will you let it go?
(Let it go!) QBism! We will not let it go!
(Let it go!) QBism! We will not let it go!
(Let it go!) Will not let it go
(Let it go!) Will not let it go (Let it go)
No, no, no, no, no, no, no
Oh mamma mia, mamma mia, mamma mia let it go!
Fuchs, Caves, and Schack have a universe that’s made for me, for me, just me

So you think that your theory is better than mine?
So you think that contextuality is fine?
Oh, crazy, you don’t think it’s too crazy
Just gotta find out: is the universe really real

*guitar solo*

It’s all really happ’ning, anyone can see
It’s all really happ’ning
It’s all really happ’ning to me
Any way my path goes

# Heisenberg part 2: Leibniz, Camus, and Kuhn (oh my!)

Continuing my commentary on Heisenberg’s Physics and Philosophy (see my previous post for more), I have a few more scattered thoughts to get down. In no particular order:

## Heisenberg, Spekkens & Leibniz

In a recent talk, Rob Spekkens argues that a principle articulated by Leibniz, often called the identity of indiscernibles, provides justification for a number of desidirata (e.g. locality and noncontextuality) that have emerged over the past hundred years for interpretations of quantum mechanics. The principle can be stated as follows:

To suppose two things indiscernible is to suppose the same thing under two names.

This has been interpreted in many ways by many different people, but Spekkens rephrases it as Continue reading “Heisenberg part 2: Leibniz, Camus, and Kuhn (oh my!)”

# Did Heisenberg have a soul?

In 1955, Werner Heisenberg traveled to Scotland to give a series of lectures which were later published as the book Physics and Philosophy (both originally in English). In it, Heisenberg lays out a (dare I say surprisingly?) cogent exposition and defense of  The Copenhagen Interpretation (a term which he coined in this work, although it turns out it’s really just his interpretation and there are a number of different Copenhagen-type interpretations) and discusses a number of related issues. The book is interesting both as a historical artifact giving insight into the thoughts of one of the founders of quantum mechanics, and as a highly accessible (if biased) introduction to issues in the ontology/epistemology of modern physics. It made me feel things, so I’m going to write a second post with various scattered reactions; but first, here’s a brief summary/background of the work, along with one of those scatterred reactions. The teaser: according to Wikipedia, Heisenberg was a devout Lutheran; did he believe in the soul, and if so, is the existence/justification of a soul central to his interpretation? Continue reading “Did Heisenberg have a soul?”