Appearance and truth: the function of «pyramidal powers» in Leonardo’s research during the last decade of the XV century

I shall show first, through the examination of texts dating from 1490-1492, that when Leonardo begins to ‘make science’ he adopts an explanatory model of a mechanical-percussive kind that he will substitute in a few years’ time with another of an optical-perspective kind. The result of this substitution is a peculiar mixture, based on a metaphysical conception of the «point» as a very real «spiritual power» similar to the soul, invisible and incorporeal because infinitely small, that by moving brings about space and the visible world and all natural effects and that can be worked out mathematically with the tools of perspective. The adoption of this model causes the level of appearances to lose its original and stable character and become derivative and uncertain. I shall then show the tension that arises when the model of «pyramidal power» as «spiritual power» is concretely extended to the explanation of appearances. On the one hand, Leonardo tends to think of the «pyramid» as a real expansion of the metaphysical «point» and thus as an entity really existing in nature; on the other hand, the difficulties he encounters push him to consider it, in line with the perspective tradition, as a mere proportion between two measures (for example, weight and speed, or volume and distance), and thus as an abstract measure.