The parable of the mischievously wise physics teacher

Physics classroom, California c. 1928

A short thought for the day” offered to the Cambridge Unitarian Church as part of the Sunday Service of Mindful Meditation 

(Click on this link to hear a recorded version of the following piece)


Imagine a physics teacher preparing an experiment in a classroom, as yet, empty of students. The students, meanwhile, are all queuing outside the door in the corridor, unable to see what is going on inside the room. 

Cricket sight-screen
The teacher has three pieces of equipment ready, a very hot radiator, a thick piece of metal sheeting placed upright on some wheels looking a little bit like a cricket sight-screen (see photo on the right), and a blow-torch. 

She takes the blow-torch, heats up one side of the thick metal sheet and then immediately wheels it in front of the very hot radiator, making sure the cool side of the metal sheet is facing towards the radiator and the hot side of the metal sheet is facing into the much cooler room. 

She hides the blow-torch from view, quickly goes to the door, invites a single student in, closes the door, takes the student up to the metal sheet and invites them to touch each side of it in turn. Puzzled, the student touches both sides again but is forced to confirm, contrary to all their expectations, that the metal screen is hotter to the touch on the side facing the cooler room, and cooler to touch on the side facing the very hot radiator. The physics teacher asks the student to think carefully about what they have just experienced, takes them back to the classroom door, ushers them out into the corridor and returns to her equipment before repeating the whole process with each of her students in turn.

Finally, all the students are invited back into the room and asked for their thoughts on what they have just experienced. Using the scientific knowledge they had so far acquired in the class, student after student offers up some kind of scientific or quasi-scientific theory or other to explain the phenomenon until, finally, one student plucks up the courage to say out loud, “You know what, I’m completely baffled. I simply don’t understand what’s going on here.”

I hope you can all see that, at last, this is was the answer for which the mischievous, but very wise, physics teacher was seeking from her students. She wanted a vivid and visceral way to remind them always to keep themselves open to what the world in its complexity is actually doing and not to let their current theories about how the world is obscure from them the fact that there are not only always things about the world we do not yet know, but there are going to be things about the world which we may never be able to know.

Our world is complex, and reality is a multifarious thing. Our existence is shaped, not only by the constant movement of matter/energy in the form of atoms and fundamental particles — some of the details of which we know about, and some we do not and may never know — but also in the form of the constant movement of wise and foolish, mischievous and malevolent people — some of the details of which we also know about, and some of which we do not and may never know.

Consequently, whether we like it or not, successfully to understand and navigate reality as best we can, we always need the wisdom provided by those sciences and philosophies which remain fully aware that alongside our “known knowns” (the things we know we know) there are always in play “known unknowns” (the things we know we do not know). And, alongside them, there will always remain in play “unknown unknowns” (the things we don’t know we don’t know).

So, next time you gratefully warm your hands on a radiator perhaps you might also give grateful thanks for the lesson of the mischievously wise physics teacher . . .