Maybe Not Probabilistic: On Grades

Physics, learning, experiment, and discovery are fun. Humor can be part of that joy. Or not. Here, the author offers a not very serious consideration of probabilities:

Schrödinger's Transcript: A Meditation on Grades (2012-02-15)

Everyone was a high school student once, so perhaps can relate to this story of disappointment. Imagine you are taking a course in the field you want to study. The teacher knows the material, relays it well, but is an extremely difficult grader and not terribly computer savvy. The school has just gone to all computer grading. You know you are on the borderline between an A and a B, have taken the final on which you knew most of the material, and are now waiting for grades to come out. The computer system is known to be difficult - moving the mouse over the wrong area brings up a different student when the teachers enter the grades. Your teacher has submitted the course grades and just gone on sabbatical to Switzerland for vacation and left all cell phones at home.

What is your grade? Since grades come in large quanta and are scalar, quantum mechanics would be the truest description of your situation. The wave function of your grade has the schematic form

Ψ_grade = (Ψ_A + Ψ_B) / √ 2

Your grade is neither A nor B, but rather a linear combination of the two, until a measurement occurs. At that moment your observation forces the grade to “take a stand”: A or B. And if you find it B, then it's really you who destroyed your chance to get into your program of choice.

So, dreading knowing, you hope your parents open the grades (this is high school, after all, and you were not yet 18 most of that time). Then you can blame them.

College students can relate, except that graduate school or a job is on the line, you have a professor, and if your scoundrel of a roomate opens the mail, you can blame someone else for the grade. Post-docs don't know if the paper is accepted or not, especially when others are known to be submitting on the same topic, so can relate through an analogous situation. Is it better to blame yourself for taking the measurement or to hope your partner is curious and takes that blame? Tough choice.

Thanks to David Griffiths, Introduction to Quantum Mechanics, 2nd edition 2005, pages 430-431.

Actually (2022-01-09), the author (usually) prefers to see that Ψ_grade probability as just a representation, which has nothing to do with setting up the situation and has nothing to do with reality or the result. The unthoughtful experimenters who put Schrödinger's cat at risk deserve any and all unkind thoughts directed at them. And those who see humor in the author's mixed state of preference are welcome.