The seven Human Design authorities, in order

In Human Design, an authority is the way a chart is said to reach a decision. Each chart has exactly one. A chart often has several defined centers, so the system reads them in a fixed order. The first one it finds defined gives the authority.

The order runs like this. A defined Solar Plexus comes first and gives Emotional authority, whatever the type. If it is open, a defined Sacral gives Sacral authority. Only Generators and Manifesting Generators have it. Next comes the Spleen for Splenic authority, then the Heart for Ego authority. Both are found in Manifestors and Projectors. A defined G Center comes fifth and gives Self-Projected authority, which only Projectors have. When none of those five is defined but the Head, the Ajna or the Throat is, the authority is Mental. That one, too, is found only in Projectors. A chart with no defined center at all, the Reflector's, has Lunar authority.

So a Generator with both a defined Solar Plexus and a defined Sacral has Emotional authority rather than Sacral. Emotional and Sacral authority between them hold most of the sample, as the table below shows. Which one a particular chart has depends on its exact birth moment, and on some days it changes with the birth time; the chart tool on this site works it out. The guide to the five types explains how a chart gets its type.