Galileo and the Phenomenal Character of Experience

Abstract Historians of philosophy widely concur that Galileo Galilei (re)introduced the metaphysical dichotomy of primary and secondary properties into philosophical discourse. However, his conceptual distinction appeared muddled, resulting in frequent misinterpretations or disregard over time. This paper aims to demonstrate that the apparent vagueness of the dichotomy stems from a common misunderstanding shaped by the subsequent distinction between two kinds of properties, primary and secondary. Accordingly, the central argument advanced here is that Galileo did not intend to differentiate between two kinds of properties inherent in external things. Instead, he sought to distinguish between the perception of spatial properties and the concurrent internal bodily sensations evoked by the mechanical impacts of external objects. Focusing on his isolation of an aspect of sensory experience, namely sensible qualities, it is suggested that Galileo recognised the phenomenal aspect of experience and thereby contributed to the early modern development of the concept of perceptual consciousness.