By Thoreau
It is news to nobody that professional physicists have tremendous self-confidence. The implications of this were driven home to me today in noticing the timidity of some students. For starters, I said at the beginning of class “The graded homework is at the front of the room for you to get.” A guy comes up and says “Does that mean I can take my homework?” I said, in the calculated demeanor of a lovable grouch that I try to project, “What else would it mean? If I say you can get it, that means you can get it.”
Later, somebody said “The homework problem asks for the direction of this vector. Does that mean you want the direction the vector is pointing in?” My answer again was “Well, what else could it mean?”
Now, I understand that they are timid. I’m not here to rant about kids these days, at least not this time. There are a lot of things that we do that beat timidity into them (e.g. emphasizing counter-intuitive things to destroy their confidence in their intuition and ability to interpret things). Also, while some schools socialize students to be go-getters (e.g. University of Special Connections, my alma mater), this school socializes students rather differently. So my calculated loveable grouch delivery of “What else could it mean?” is to try to get them to think and present themselves differently.
Some of this is career skills, but I think it also goes to the heart of much of theoretical physics. There’s a style in theoretical physics that says “I may not be able to construct a detailed model, but I know that the answer can only depend on these variables, and there’s only one way to combine those variables that gives the right units (or lack of units) and/or has the right scaling in a limiting case. So the answer must be proportional to this, no matter how the details work out.” Making that statement requires a tremendous amount of confidence. What sort of pompous ass feels that he can ignore details, assert that only a few things can possibly matter, and then combine the variables to get the units right and declare that the answer must be right? Who can be so confident that they can assert that nothing else could matter besides a few variables?
Experimentalists have a bit of a similar thing. They may not project the egos that theorists project (though God knows some of them can be insufferable), but doing delicate and indirect measurements requires confidence that you understand your chain of cause-and-effect that leads from the delicate phenomenon you care about to the readout on your instrument. Yes, experimentalists are cautious about checking every link in the chain of instrumentation, but it still requires a lot of confidence to say “Watching the fluctuations of the light scattering from a diffusing particle must give us information on the viscoelastic properties of the medium.” Or “If I get too many events where a nucleus jitters slightly, after I’ve checked the shielding and background level, it must be because a sub-atomic particle hit the nucleus.” No matter how carefully they check their laser and detector and every wire in the setup, they have to have huge confidence about the physics to go from flickering light to viscosity, or from vibrating nuclei to subatomic dark matter particles. And yet they do it.
