Family therapy is both a thinking system for therapists, as well as a description of therapy with family members.

As a therapy approach, the therapist sees the family as an integrated entity, with the participants actively sustaining their place and function within the family system.

Driven by their own psychology, a family member will do what is emotionally and psychologically necessary for their stability within the family system.  

Ideally my happiness rests on your happiness.

Ideally too, my happiness has developed from the context of a loving, emotionally and physically safe childhood family, so that the happiness I strive to maintain in adulthood, rests on these principles. 

And since no one has an ideal family, we have family therapy instead, to motivate us to more closely create such peaceful happiness!

In an actual family therapy session, the nuances, contradictions, hidden motives, true nature of both sides of a relationship story are accessible in real time.  

The emotional logic of one person drawing from another, is no longer a retelling of a recent episode. 

 In the family therapy session, the therapist can directly intervene in a dynamic, so both sides learn about themselves in real time.

Sometimes self-doubts of one family member who has tried for a long time to get their point across, suddenly realizes the reason for not being heard is because the other family member doesn't want to hear them!

Family therapy gives its members a chance to witness the emotional logic of the others, without themselves being a participant in a dialogue.  The therapist guides the session.  The family members are in the unique position of hearing and observing the others think out loud.

Basically, family therapy allows in live and interactive format, many of the problematic situations which individual therapy addresses only in an intellectual way.