Physical Symbol System Hypothesis

The Physical Symbol System Hypothesis (PSSH) was proposed by Allen Newell
and Herbert Simon in 1976:

A physical symbol system has the necessary and sufficient means for general intelligent action.

In other words: anything that can create, manipulate, and combine symbols to
solve problems is intelligent — and only systems that do this can be intelligent.

This is a hypothesis, not a theorem. Subsymbolic and embodied AI researchers
often challenge it, arguing that symbol manipulation alone is not enough.

The PSSH is the founding manifesto of symbolic AI and the reason this course
exists.