  Although space was put forward as the main principle of the physical, the three derivative principles also play important roles in Patrizi's model. The primary occupant of space is light; from it in turn heat is produced, which is construed as a formal and active principle. It is probably no coincidence that heat had been one of the three basic principles underlying his colleague Telesio's system of nature, together with cold and matter, although Telesio's was a qualitative rather than quantifiable universe, as Patrizi's would be. The final constituent of Patrizi's physics is humidity (fluor), which is passive and material and somewhat akin to the elements associated with pre-Socratic thinkers such as Empedocles.