Metaphysical knowledge of nature

In his introduction to La géométrie dans le monde sensible (Geometry in the Sensible World), philosopher Jean Nicod observed in 1923: "The discernment of the sensible order that surrounds us, that forms the fabric of our life and our science, that is so present to us and yet so indistinct, what philosopher would not be curious about it, even if his metaphysics were to expect no help from it? The aim of this year's lessons was to show that a philosopher's curiosity can sometimes be rewarded, and perhaps even help his metaphysics itself. Indeed, it would be a pity if this were not the case, since the metaphysician is in every philosopher - as, indeed, he is in every one of us, since metaphysics (even bad metaphysics) always rests, as Charles Sanders Peirce noted, on "observations", and the only reason it is not recognized is that everyone's experience is so saturated with them that they usually pay no attention to them.