“Feedback” is a hugely important phenomenon. It plays a key role in all goal-oriented, dynamic systems, from living organisms to self-driving cars. Feedback is information that tells a system how it is doing in relation to its goals and guides its behavior over time. (Feedback systems are often referred to as being “cybernetic”, after the Greek word for “helmsman” – kybernetes.) Positive feedback tells the system to continue doing what it is doing, or even to do more of it. And negative feedback tells the system to change its behavior.