priors
Explanation
This comic plays on the dual meaning of the word "priors" in a parent-child conversation. A child asks, "Mommy, where do priors come from?" In Bayesian statistics, "priors" (or prior probabilities) are the initial beliefs or assumptions you bring to a problem before observing new data. This is a common topic in statistics and philosophy of science.
The mother gives a whimsical, fairy-tale-like answer: priors come from "a magical field where flowers blossom and butterflies dance" -- essentially making up a comforting bedtime story rather than explaining Bayesian reasoning.
But the word "priors" also has a colloquial meaning in criminal justice: a person's "priors" are their prior criminal convictions. The comic then shifts to a darker register, with the mother in bed muttering about how "every good-looking person, every bad-memoried, sweet, and misremembered person" has priors -- suggesting she's actually thinking about criminal records, past mistakes, or hidden histories.
The punchline works through the double meaning of "priors." The innocent, childlike question about Bayesian statistics gets a fairy-tale answer, but the mother's private thoughts reveal anxiety about the more colloquial, darker meaning of the word. The humor comes from the collision of these two meanings: the clean, mathematical concept of prior probability versus the messy, human reality of everyone having a problematic past. It also satirizes the way parents give simplified, sanitized answers to children's questions while harboring much more complicated and troubling thoughts.