(Exploring a projected set turns out to be less and less possible at each projection.) x² = -1 Thus are born what we usually refer to as extensions, with the hope of giving answers to questions with no answer. But questions with no answer are not unanswerable questions. Why do we try to give them answers? They're already answered! Extensions only narrow our field of vision. They imprison the mind into a comfortable jail of abstraction. The smallest sets are the most fruitful.