Once the catalyst leaves, however, his or her presence is still felt. The catalyst is an inspirational figure who spurs others to action. Circles don’t form on their own. Put a bunch of people in the same room together, and they might talk about the weather in random groups of twos and threes. Add a catalyst, and soon they’ll be sitting around in a circle discussing their shared love of skiing or antique lampshades. A catalyst develops an idea, shares it with others, and leads by example.