The five Human Design types are not five independent categories. They are the outcome of a small number of yes or no questions asked of a chart, and knowing which questions they are makes the typology legible.
A mechanical rule
Human Design calculates a chart from a birth time, marks which of the nine centres come out defined and which open, and reads the type off that pattern. The Generator turns on the state of one particular centre, the Sacral. The rule is deterministic: the same birth data yields the same answer every time, which distinguishes the classification from an interpretive one.
The count of five is not inherited
Of the four systems Human Design draws on, none sorts people into five kinds. The I Ching has sixty-four hexagrams and no typology of persons; the chakra model describes a structure held to be common to everyone; astrology classifies by other means entirely. The five types are Ra Uru Hu's own addition, published in 1987.
What has not been shown
There is no independent evidence that people classified as Generators differ from people classified otherwise in the ways the system describes. Such a claim is in principle testable, since the classification is mechanical and the predicted differences are stated, but no published test establishes it.
This atlas records the system as its author set it out, and records that status honestly.