An aphorism is a short saying that requires interpretation. During the Renaissance, there was a rich biodiversity of the short saying: commonplace, gnomē, paroimia, proverb, sententia, precept, maxim, adage, epigram, and apothegm or apophthegm. It is no exaggeration to say that the microform constitutes the synapses of the humanist mind. It was used in medicine, science, philosophy, theology, popular devotion, law, literature, rhetoric, military strategy, politics, and popular wisdom. The key theorist of the short form was Erasmus, who writes: “a proverb is a saying in popular use, remarkable for some shrewd and novel turn.” A Renaissance schoolboy would have encountered aphorisms as commonplaces through rhetorical textbooks known as progymnasmata, a series of exercises that moved progressively from the easy to the difficult. Calvin, John Dee, Guicciardini, Gracián, Matteo Ricci, Shakespeare, Cervantes, and Sidney all used aphorisms in their work. Bacon adapted the humanist practice of accumulating aphorisms to a scientific vector for discovering new knowledge.