 We shall soon see that astronomy occupies a particular place in the system because its subject results from optical observation. Logic is the fifth and last division of philosophy and focuses on properties that beings acquire in the human mind; “because of such properties and their knowledge [logic] becomes an instrument for apprehending the right and the truth in beings” (IB-taaliq: 28. 13–14). Avempace remarks that for this reason some people consider logic to be only an instrument and not a part of philosophy, but insofar as these properties have real existence, logic can be integrated into philosophy. He concludes that logic is both part and instrument of philosophy.