principles.fyi · the brain · concept

superposition

One neuron quietly does several jobs by sharing its space.

features stored >> neurons available, so directions overlap

A model has fewer neurons than ideas it wants to remember, so it folds many ideas into the same small space, each pointing in a slightly different direction. Because the directions overlap, one neuron ends up helping with several unrelated things at once. That is why peeking at a single neuron is confusing: it is never about just one thing, it is many things stacked on top of each other.