Representation (Not Rightness) Rules

Which is a more correct representation of a beloved member of your life—an audio recording, a photograph, a video recording, a pencil sketch, a realist portrait painting, or an abstract painting?  That’s the question I keep asking myself every time I think about analogies, metaphors, and representations in physics.

The classic example of a representation challenge in physics is wave-particle duality:  do particles act like little billiard balls?  Or like waves moving through a non-existent medium?  The answer is they act like both.  The challenge is, as realities, they feel mutually exclusive.  But, as representations, the act as complements.  Each representation, either wave-like or particle-like, gives a framework for describing how a fundamental object, like a photon or an electron or a neutrino, will behave under certain circumstances.  Both representations are right in the sense that they will produce precise, numerical results that can be calculated and will match observed values.

In the same way, if I gave you a photograph of a close family member in my life to try and describe their behavior—how they interact with the world—you would gain one kind of understanding.  If, on the other hand, I gave you an audio recording of that same family member, the information would be complementary to what you learned from the photograph, but completely different.  Obviously though, we don’t cry foul and say, but how can the person be invisible voice waves and a static two-dimensional color object at the same time, and what does this have to do with their behavior?

That’s because we understand that they are representations of a thing and not the thing itself.  Of course, from an intellectual standpoint this argument is partly philosophical and psychological and has had volumes written about it.  But from a practitioner standpoint there’s no challenge: both representations are valid, and the combination gives a better understanding than either one representation alone.  In fact, in the close family member’s behavior analogy it’s easy to see that having more representations is better, because each added representation layers our perspective with additional understanding.

If I were trying to discover something new about someone else’s family member it might even help to force me to use different representations: an audio recording might tell me about how that person speaks or interacts with others, a photograph might show me that person’s physical characteristics and the kinds of events they participate in, an abstract painting might tell me what about that person most captures someone else’s perception.

In physics, having multiple representations of the same physical system can do the same thing, especially since most of our studies want to know about the behavior of something (its dynamics), but most representations are static (don’t move).  Words and math sit on a page.  Photographs sit frozen in a flat plane.  Videos sit in a flat plane and replay a sequence of still shots at high speed over and over.

At least with a living family member we can go meet them in person.  We can set aside the photograph.  We can ignore the voicemail.  We can turn off text and video messaging and go get all that experience in real-time, face-to-face.  Not so in physics.  The simulated photographs, the recordings, and the equations are as close as we will ever come to some members of nature’s family, especially in particle physics.  Biology, geology, and the social sciences, to name a few, have the advantage over particle physics, in that respect.  Though any investigations into the past are equally handicapped by lack of direct access.

So, it seems to me we need to accumulate as many representations and models as we can get our hands on.  Aim for a collage, not a pixel.  No one representation will ever be all things to all situations.  Because no representation will ever be the real thing.  By narrowing down representations to “the right picture” instead of generating representations to get “the right mix” we cut off a route to discovering something new.  After all, when we allowed both the wave and particle representations into physics we opened the door to countless previously inconceivable and undiscovered phenomena, like neutrino oscillations (the ability for a neutrino particle to spontaneously change particle type as it travels, which relies on quantum mechanical wave interference between its constituent parts).  When it comes to conceiving of the inconceivable, representation, not rightness, rules.