Our attention is built to notice what's present: the thing that moved, the sign that's lit, the complaint that's loud. What's absent barely registers. Nobody notices the students who never come in, the question nobody asks, or the hour when the room sits empty. Yet those gaps are often where the best opportunities are.
Absence Thinking makes the missing visible on purpose. Instead of asking what's wrong with what's there, you ask four questions about what isn't: what's missing, who's missing, when and where nothing happens, and what nobody does. Each gap becomes a question, and each question is a possible idea.
Use it when you're stuck on the obvious, you're searching for an unmet need or a new audience, or the people you most want to reach are the ones who never show up.