The development of human cognition starts with the ability to perceive
things, i.e., entities. Of man’s five cognitive senses, only two provide
him with a direct awareness of entities: sight and touch. The other three
senses—hearing, taste and smell—give him an awareness of some of an entity’s
attributes (or of the consequences produced by an entity): they tell him that
something makes sounds, or something tastes sweet, or something smells fresh;
but in order to perceive this something, he needs sight and/or touch.
The concept “entity” is (implicitly) the start of man’s conceptual development
and the building-block of his entire conceptual structure. It is by perceiving
entities that man perceives the universe.