We have many chemical and physical properties in our bodies, the motion of the heart has a physical quality but the effects on food is a chemical substance and examples like this are many in our body.
If the spirit, thought and reflection were all material and had physical and chemical quantities of the brain cells then why among them and our other physical properties is there a great deal of difference?
Our thoughts, ideas and spirit relate and correct us to the external world and make us aware of that which passes outside but the chemical particularities of the stomach and the physical motion of our eyes and tongue and heart never has such a state.