The Law of Raspberry Jam

Definition

"The wider you spread it, the thinner it gets." Any act of helping — consulting, teaching, writing, publishing — faces a hard tradeoff between how many people it reaches and how much of an effect it has on each one. Weinberg states the compressed form directly: "Influence or affluence; take your choice." No amount of cleverness lets you make the jam both thicker and wider at once; it is, in his framing, as inescapable as the first law of thermodynamics.

In the Book

Weinberg builds the law from his own career ladder — dishwasher, consultant, trainer, lecturer, author — tracking both reach and income at each rung. As a dishwasher he gets total, immediate, intimate control over one job's outcome; as a consultant he can advise two clients in the time it took to wash a hundred mugs, but the outcome now depends on whether the client actually implements the advice; as a trainer he reaches fifteen or twenty people per workshop, each getting "a little less"; as a lecturer, hundreds at once, some of them "sleeping with their eyes open"; as an author, potentially millions, with proportionally less of himself in the interaction. Income rises down this ladder (dishwasher's $9,000 versus author's $150,000, in his figures) exactly as personal, verifiable impact per person falls. He explicitly rejects the idea that the tradeoff can be evaded: shouting through a megaphone, training a disciple, or building a university "will [not] thicken the message by so much as a single cubit."

Why It Matters

This names a scaling tradeoff that shows up whenever anyone chooses between depth of impact and breadth of audience — a manager choosing between one-on-one mentoring and an all-hands memo, a doctor choosing between a private practice and public-health messaging, a teacher choosing between office hours and a MOOC. It reframes "why doesn't scaling this up work as well" from a failure of execution into an expected consequence of the tradeoff itself, and it forces an explicit choice — which axis matters more for this goal — instead of an implicit assumption that scale is free.