 The concept of the temperaments or humoural mixtures in the human body was originally developed to describe physiological body states: “The four humours were real body fluids, to which largely hypothetical origins, sites, and functions were ascribed” (Siraisi 1990: 105). In late Antiquity and in the Middle Ages, the temperaments were understood to fall under the reign of the stars, which influence the generation and corruption of bodies in the sublunar sphere. In an important conceptual step, Porta turns the tables, contending that rather than being controlled by the stars, the medical humours are actually universal descriptors structuring the entire cosmos. With this move in a naturalistic direction, Porta strove to eclipse the astrological elements of his theory. Even though in the Coelestis physiognomonia he had declared astrology a vain discipline, Porta added an important qualification to this dismissal: astrology is an erroneous art, but only as long as divination from the stars is not based on the perceptible features of heavenly bodies. Hence, a fine physiognomonist will swiftly derive the relevant temperamental features from the visible appearance of the planets. In this way, all natural bodies remain substantiae signatae, cosmically predisposed substances bearing inscriptions of universal signs. The astrological system of categorization was restricted to the medical temperaments, thus associating celestial bodies with a system of signs that pertained to medicine and hence to a lower level in the hierarchy of being. Instead of governing the lower bodies, the stars become subject to the same laws as earthly bodies (Coelestis physiognomonia, proemium, Paolella 2004). According to classical medicine, diseases are caused by an imbalance between body fluids—the temperaments. This was a notable shift in terminology and concept: for in the first version of the Magia naturalis, Porta had maintained that form had been the decisive factor for the occult property of a thing: now he aligned these properties to elemental qualities (Verardi 2018).