Bernardo Telesio (1509–1588) studied philosophy, physics, and mathematics at the University of Padua, receiving his doctorate at the age of 26. His subsequent pedagogical activity consisted of conversations with friends under the patronage of the Carafa family in Naples. He was also sought after by Pope Gregory XIII (1502–1585), who invited him to Rome. Telesio’s major work was On the Nature of Things According to their Principles.

Telesio’s innovation was to propose that knowledge of nature be based on sensory information about matter and the forces of heat and cold. Because of this emphasis on sensory information, Telesio is credited with laying the groundwork for more rigorous ideas about scientific investigation, which would soon follow in the work of Francis Bacon (1561–1626) and Galileo Galilei (1564–1642). However, Telesio’s own theories about the workings of nature do not greatly depart from Neoplatonic perspectives.

According to Telesio, heat, represented by sky, is the source of life and the cause of biological functions. Cold is represented by Earth, and it opposes heat. Heat also emanates “spirit,” which in animals and humans is located in the brain, for the purpose of anticipating and receiving sensory information. Man also has an anima superaddita, or mind, which is created by God and present in both spirit and body. All beings have a desire or impetus toward self-preservation, which in human beings includes a goal of everlasting life.