Definition
Radical thinking is the practice of returning to the root of a question — examining the assumptions everyone else takes for granted and asking whether they are actually true. The word radical here means to the root, not extreme; it is a form of intellectual independence.
Robert Greene presents radical thinking as a deliberate counter to the mind's tendency to absorb conventional opinion without scrutiny. Most people, he notes, think in inherited categories; the radical thinker checks those categories first.
Why it matters
How it works
Radical thinking starts by identifying the assumptions in play — the beliefs that frame how a problem is currently understood. The thinker then tests each one: is it grounded in evidence, or merely in habit and convention? Discarding the unfounded assumptions clears space for a fresh view.
Greene pairs this with intellectual courage. Questioning consensus invites discomfort and resistance, so radical thinking requires the willingness to stand momentarily apart from the crowd. The reward is access to insights and strategies that those bound by convention cannot reach.