that states that when a person perceive
s an object
, the object of awareness is not the object itself, but a sensory experience
the object. The person is not direct
ly aware of reality
This argument is closely related to the theory of Immanuel Kant which states that there is a object which exists in itself, but human perception can not learn anything about it. Rather, humans can only perceive a "presentation" or "representation" of an object.
A common objection to these types of theories is that claiming that human beings can't know anything about the world in itself is a knowledge claim about the world in itself.