 In other words, at this stage, Bacon is mainly concerned with Aristotle’s definition of experience in the Metaphysics and Posterior Analytics, although one already notices that he relates the Aristotelian subject matter to the discussion in Alhacen’s Perspectiva. Nevertheless, it is also important to note that these Aristotelian concerns with Experimentum are repeated in 1267 at the beginning of Opus majus, Part Six on exprimental science, and thus, Aristotle’s Metaphysics, Posterior Analytics and Meteorology together with the Optics of Ibn al-Haytham will form the necessary philosophical background for Bacon’s laterc. 1266 notions of the experimental sciences.