What this center is about
The Ajna compares, analyzes, organizes and puts things into words. It's an awareness center, but not a decision center: the mind sees options well, yet on its own it doesn't know what's right for you. Most people still hand authority to the mind and pay for it with anxiety and mental restlessness. Biologically the Ajna is linked to the pituitary gland, the master gland that sends hormonal instructions to the whole body.
There are three ways of thinking in the Ajna, three "operating systems": abstract thinking (the stream of gates 64–47–11–56), logical thinking (63–4–17–62) and individual, knowing thinking (61–24–43–23). In a defined Ajna one of them is fixed.
Defined Ajna
A defined Ajna means a consistent way of thinking: the person always looks at the world from a certain angle. This isn't about the content of thoughts, since views can change, but about how they think. Such a mind is reliable and consistent, and that very reliability tempts them to believe it's right.
Trap of the defined Ajna: believing your way of thinking is the only correct one and pushing others until they agree. This works especially easily on people with an open Ajna.
Open Ajna
An open Ajna has no fixed way of thinking. Around logical people they think logically, around abstract thinkers they think abstractly, and on the same topic they can reach opposite conclusions. That's flexibility, not weakness: such a person can understand any point of view.
Trap (not-self): pretending to be certain. Either grabbing someone else's beliefs and defending them all the more fiercely the less sure you really are, or endlessly searching for "the Truth" and collecting libraries of concepts.
Gift: an open Ajna doesn't have to have a final opinion. Its value is in seeing many perspectives and understanding how different people think.
A question to ask yourself
Am I pretending to be certain when I'm really not?