De natura juxta propria principia

De natura juxta propria principia (On Nature According to Its Own Principles) is the seminal work of Bernardino Telesio, an Italian philosopher and natural scientist of the Renaissance. Published in two parts, in 1565 and 1565, the book marked a significant shift towards empiricism in the study of nature.1

Telesio argued that understanding the natural world requires direct observation and attention to physical properties, rather than relying solely on abstract reasoning, which was characteristic of Aristotelian philosophy. He proposed that heat and cold are the fundamental active principles governing all natural phenomena, with heat being the source of life. This emphasis on sensory evidence and empirical data led Francis Bacon to consider Telesio "the first of the moderns". Despite his empirical approach, Telesio maintained beliefs in God, the soul, and immortality. His work influenced later thinkers like Tommaso Campanella and Thomas Hobbes.1