what is physics?

Well, here I am late to the party.  I can hear Jen-Luc chiding in the background “You know, there’s a fine line between ‘fashionably late’ and ‘who-the-hell-does-she-think-she-is?’.” My excuse is that I just moved my household (and lab) from Nebraska to Dallas. I know that was in May, but I’m still struggling to finding my way around.

As you might guess, there is a distinct culture change going from Big Red to Big D, from UNL to UTD and even from one physics department to another. The negative of moving is broken equipment and trying to figure out formerly simply things like ordering pump oil and figuring out how to dial local numbers that still require an area code.  The positive is that my new job came with a new family.  I have acquired a number of uncles, a little brother to protect, and a big brother I can pass notes to or kick under the table at faculty meetings. 

We’re in the process of doing “strategic planning”, a masochistic exercise I’ve never been involved with quite this intimately. (One of the benefits of academia is that you aren't asked to be one of the adults until you've reached at least 40.)But this exercise is where the big similarity with every physics department I've ever worked in has come through.  When talking about future directions, one refrain keeps coming up over and over, usually when certain fields or experiments are mentioned: “...but that’s not physics”.

My colleague the Rocket Scientist (yes, I have a friend who actually is a rocket scientist!) framed the question best. I am fairly sure RS has an honorary J.D. (Jurus Devilus), since he enjoys being the devil’s advocate so much. You can tell when he's going to do it because he looks just like the kid at the zoo standing over the fish pond dropping the fish food pellets into the water just to see the fish come rushing over, pushing each other out of the way with their mouths all agape.

RS argues that, as science rushes toward interdisciplinarity, perhaps, “to preserve the sanctity of the discipline”, we should restrict ourselves to focusing on the “traditional areas of physics”, like cosmology, relativity, particle physics, etc. I call this position “heterophobia” – the fear of diluting physics by mixing it with other sciences and/or (gasp!) engineering. Maybe, RS continues, in order for physics to retain its identity as physics and not turn into the scientific equivalent of the classics department, people working in areas one might consider “possibly not pure physics” should affiliate with other departments.

That would be me he is talking about. My research has shifted quite a bit in the last five years from basic magnetism toward nanomedicine, so I could be at home in a materials science department, a bioengineering or biomaterials department, or probably even in a chemistry department. So I had to wonder: Am I still a physicist? Although RS would also be one of the people kicked out if we decided to become a 'pure' physics department, he is a degreed engineer, so he has no idea of the epistemological crisis his mischief caused.

I’ve been traveling giving a lot of talks lately, and I always ask people I'm visiting what makes physics “physics”. Why is biophysics bioPHYSICS and not BIOphysics?

Research has always been problem driven. The big difference between the problems I worked on as a graduate student and the problems on which I work today is that today’s problems are much more complex and far-ranging.  No longer does a single scientist have all the tools he or she needs to solve a problem alone. Collaboration is not just a collegial thing to do, it is essential. We’re also being asked to look at our impact on society more closely. Those of us in condensed matter have a wide range of things to pursue from very applied to not-at-all-applied. Some people rankle at the idea of being told to work on ‘nano’ or ‘energy’ or ‘green,’ but the reality is that funding is getting harder and harder to get, and if you want to run a lab, you’ve got to have money.

It was during a discussion at a physics department I was visiting that I arrived at the answer. It is ironic, because I routinely make the following argument to K-12 students and/or teachers. Science is not a body of facts: It’s a way of trying to understand the world. I’m not sure why it took me so long to extrapolate that belief to this question of what makes something physics. What makes a discipline is not the system you study, but the tools, approaches and context you bring to the study of that system.

So what makes physics physics? Without trying to suggest that one discipline is better than the others, I think the most fundamental distinction is that physicists believe that the universe can be understood and described using mathematical models. Most physicists hold a deeply seated belief that those models ought to be universal and (ideally) not complicated.

If you create a continuum between “how” and “why,” I think it’s fair to say that physics is much more strongly skewed to the “why” side than it is to the “how” side. Physicists like to look at things in terms of their fundamental building blocks (i.e. magnetism by the atom, not by the material). As an experimentalist, I would claim that a distinguishing characteristic of physicists is that we are much more comfortable designing and building what we need than, say, most biologists are.

Finally, the cosmologist down the hall took pretty much the same courses in undergraduate and graduate school that I did, even though he thinks about lofty things like dark energy and I mostly change pump oil and measure the magnetism of rat livers.  We share a very broad common background of fundamentals and that isn't the case in some other disciplines.

It’s not that biologists look at cells: It’s that biologists look at cells through the eyes of biologists. Physicists see cells differently, so they see different problems. Even when they see the same question, they go about answering it in different ways. What makes something physics is that it's done by physicists. So regardless of what department is listed on my business card, I will still be doing physics because that is what I was trained to do. Crisis averted.

Comments

[Jennifer Ouellette]

Late is better than never! Congrats on a great first post, and on getting settled in your digs (both offline and on)...

["It'll be just like starting over..."]

Diandra:
If some physicists give you smack for having an open mind and an experimental spirit, then perhaps you might want to remember that you're in good company.
The bests physicists in history not only played melange games with different fields of physics, they regularly left it behind for other visionquests altogether...
One of Einstein's favorite pasttimes was his passionate love affair with his violin. It seems that he didn't suck, either.
The press once asked Oppenheimer what he would have done if he had never pursued the nuclear option as a specialty in physics. They were left in slackjawed disbelief when he told them that he regularly wished that he had focused instead on his Other Great Love: Poetry.

[Lee Kottner]

Hi Diandra! Welcome aboard!

Just wanted to say this constant sorting of disciplines always felt like a ridiculous and artificial distinction to me anyway. I ran into a very similar situation when I was considering doing a dual Master's in English and history. One of my advisors told me historians couldn't do English criticism and litcrit people couldn't do historical research. Since I was a medievalist at the time, and in that period you could hardly separate literature from history, that made no sense to me. Still doesn't. And why does it even matter that much? If everything is reducible to physics, that makes everything physics at some point. But I think you're right on the money when you say physicists do physics no matter what department they're in. We all look at problems in the way we were trained.

[Ponder Stibbons]

Large swathes of mathematical biology (e.g. theoretical population genetics) use mathematical models but aren't considered biophysics. So I don't think the fundamental distinction is the use of mathematical models. I think the distinction is more institutional --- as you said, biophysicists tend to have taken the same courses as cosmologists.

[Weldon MacDonald]

In a master level E&M class, one of my fellow students was a chemist, making the change to physics. I was reminded of a summer I spent in my undergraduate lab on loan to a physical chemist trying to do some raman spectroscopy. I mentioned that in technical conversation, you couldn't tell a physical chemist from a physicist, and he replied, "yes, but as a physical chemist you spend your time with chemists, not physicists, there's a difference in the way they see things".

["It'll be just like starting over..."]

In classes at school I was always the kid with the chronic propensity to raise his hand with answers. This meant that teachers and profs loved me for participating so much in class, but I always paid for it at recess.
So forgive me for my current prolific class participation.
I think what we're really dealing with here is a new twist on an old phenomenon of the sciences and arts...
I call it The Specialist Versus The Generalist.
In war, it is reflected in the rank names. A "private" isn't really that concerned with much else besides doing what he is told, staying out the way, and not getting dead. This really isn't his fight. He would normally just be a "private" citizen. Probably doesn't vote much, either. Even the word "corporal" might reflect the guy who is more concerned with his own skin than any grand strategy. It might also be a way of implying that these are the specialists who make up the "body" of the army. The "General" is concerned with everything, every tiny scrap of information about the current battle, and then trying to dream up a bizarre and innovative way to adapt to the enemy and the battle and do the unexpected thing to win.
Same in science and the arts.
As far as music goes, my favorite bands are all always the ones in which you aren't sure if the bass player, drummer, or vocalist will be playing bass on the next album. And the song lineup wanders through genres like a schizophrenic changes his story.
Same is true in science. The vast bulk are just going to do EXACTLY what they were taught in class, nothing less, but nothing more either. Ingrained and taught methods of thinking lead to a concrete, but unoriginal, approach to science. More concerned with not looking publically like fools than seeing their field with an innovative perspective, these are the guys you younger geniuses have been submitting your papers to. I wouldn't be hurt or crushed if "your crazy new ideas" are treated as exactly that.
Me, I'm with the heretics. It leads to a short life and a painful, fiery, death. But OH! the epiphanies that come!
A specialist is VERY concerned with the comma splice, the semicolon at the end of the C++ line. You have to have them, and every decent poet is secretly a spelling nazi and a decent programmer doesn't have to spend five hours in debug to find that the only mistake was the forgotten semicolon.
And Einstein sucked at math.
But the difference is that the Generalist's only real rule is to break all the rules. Generalists do their best science while asleep. The Great Breakthrough might come while walking down the street, or while painting. A Generalist keeps his mind open as much as possible, and tends to daydream. A generalist is a kid at heart. A generalist learns everything possible about ANY field, and can see the value in music, sailing, games, lesbian porn novels, biology, animated YouTube vids, anthropology, or having long coversations with his cat, as much as he knows everything about astrophysics or computer programming. It is that ability to shift back and forth between diverse topics and see how they might be connected through the use of analogy and metaphore that can often lead to a brilliant new perspective. And it is also how the human brain tends to work in general. We aren't computers who process data in serial fashion. We humans suck in everything, and process in parallel and on multiple levels of consciousness. Who knows what tiny, seemingly irrelevant scrap of triviality might later be seen to be the key to understanding singularity and The Multiverse?
Like Heinlein once wrote: "Most scientists are bottle-washers and button-sorters."
And besides: It's more FUN to be Buckaroo Bonsai from the 8th dimension.

[onymous]

The formulation I like is "physics is what physicists say physics is." (Not the slightly different "physics is what physicists do.")

["It'll be just like starting over..."]

True that.

[RD Padouk]

I kinda like the idea of Physics as the technical equivalent of a humanities degree. It prepares you for anything. I have a Master's in Physics, and have never done research. Yet, I cherish my Physics experience because it taught me to think about things in a highly conceptual way coupled with an appreciation for technical constraints. I have found this ability to be extremely useful.

[President Zaphod Beeblebrox! (The Artist Formerly Known As "It'll be just like starting over...")]

RD Padouk: you made me think of that Asimov "Foundation" series novel in which the descendants of Seldon's Foundation have to match wits with the people of The Second Foundation. The First Foundation were all physicists and scientists, using what remained of the knowledge of the Old Empire and the approach of empirical science and technology. The Second Foundation were all intutive artists who use extra-sensory perception to do their work. (It's been so long since I read those books that I don't remember if they were allies or not or how it turned out.)

But I think it's a bit like all of us in here.
We have our scientists, like RD, who try to bring an empirical and logical rigor to their thoughts and explorations. There is obvious merit and benefit in this.
And then we have our artists. We use our intuition to do our work, we daydream, and dream our songs and stories and paintings into being.
The connection is that we are all trying to undertand the modern world around us through the use of modern tools like this electronic tube that delivers our thoughts at each other.
Sometimes the subject of our experiments is Fomalhaut b, and sometimes, at some future point, we'll sail right on past it.
But it is our logic and our intuition that fuel the engines of our starship and plot the course on our holographic astroprojector.

[Allison]

Thanks for this post. I'm a physics grad student working on learning enough biochemistry and biology to do meaningful work in biophysics, so I've been thinking about this a lot. Currently I'm the only person with a physics background in my biophysics seminar.

I've noticed that biochemists and biologists tend to be more applied, whereas physicists tend to get really excited about what we can do and tend to be more "pure science". I think this relates to your distinction between "how" and "why." It definitely agrees with my observations.

A biology professor I was talking with about this noted that physicists like to reduce everything to one reason- reducing the greatest number of phenomena to the minimum explanation- and biology doesn't always work like this. It is messy, it takes multiple pathways, etc.

Also, most baffling, I've noted a dialect difference: biologists say "in lab" and physicists say "in my lab" or "in the lab." Why no article guys? :)

Anyway, I am hoping that I'll be able to advance the biological sciences by attacking the problem from a different angle. And being good at building stuff.

Looking forward to more posts from you!

[exploration xrf]

Physics is the scientific study of matter and energy and how they interact with each other.
This energy can take the form of motion, light, electricity, radiation, gravity,just about anything, honestly. Physics deals with matter on scales ranging from sub-atomic particles to stars and even entire galaxies.