Ep.4/ HD Authority
TL:DR - Your mind is NOT the place for decisions. Listen to the wisdom of your body.
Trying to make decisions with the mind is like trying to set a budget without knowing what's in your bank account. Yes, you may have more than you think you do, but more than likely, you'll find yourself overdrawn and broke.
Similarly, when you make decisions with your mind (personality) rather than your body (design), your mind writes checks your body may not be able to cash. The mind isn't in touch with what resources the body has available or with how the energetics of the body are wired. Instead of being overdrawn on your bank account, you end up feeling burned out, depressed, anxious, and perhaps even with chronic illness.
But how, then do you 'make decisions through the body?' you might (rightly) ask....
Via your authority.
Strategy is how you interact with folks around you; authority is how you interact with yourself. How you make decisions that will serve you in the short and long-term.
There are seven authorities:
Emotional
Sacral
Splenic
Ego
G-center
Mental
Open
The type of authority you have is determined by the lowest defined center in your chart, starting at the solar plexus. If your solar plexus is defined, you'd have an emotional authority. If you had an open solar plexus and sacral center, but a defined spleen, you'd have a splenic authority. Through to no defined centers (if you're a reflector), where you'd have an open authority.
A common pitfall when folks are learning their design is that they'll become paralyzed about every decision and using their authority. Remember that Human Design is a tool, not a book of laws or rules or a dogma. Use for what it is to help you build up confidence that you absolutely can trust yourself. Practice using your authority for small things to build up some confidence. See what unfolds as you go. Then, when big decisions come around (life partnerships, career choices, moving, etc) you'll have a strong base of evidence built up that you can, in fact trust yourself.
Authority in Human Design is the closest thing we have to articulating how to make sense of intuition in a systematic way.