In this introductory description of Aristotle, there is a dialogue between the teacher, Plato, and the student, Aristotle.  The teacher refers to Socarates and Science.  And the Student refers to the ideas and the matter or things.  Plato believes all matter has a spirit and Aristotle believes all things are outside the spirit.  He realizes his ideas come from spirit like Plato, but he does not subscribe to the spirit of things.

Aristotle proves his theory that ideas only describe things and that their true physical selves must be explored to find what idea fits to the corresponding object.

Plato:  Is Socrates right about things?

Aristotle:  In that things have no spirit.  I am certain because I dissect things and find no spirit.

P:  Yes, you find no spirit because there is no sense to measure spirit.

A:  No, you can measure everything and that which can not be measured is absent from the object.

P:  A+B is not equal to C;  A+B+C=D

A:  A+B=C;  A+B=O

P:  Your math is too simple.  You remove all spirit from things.

A:  Yes, there is no spirit in things.

P:  But God exists in all things.

A:  No, God may not exist.  He can not be found or seen.

P:  Perhaps.

A:  Certainly, but yes, he may exist.  I can not disprove the existence of God.  But I can

define all things.

P:  Not in my life time.

A:  Very well, I will do it after your life time.