 Schopenhauer saw the human will as our one window to the world behind the representation, the Kantian thing-in-itself.He believed, therefore, that we could gain knowledge about the thing-in-itself, something Kant said was impossible, since the rest of the relationship between representation and thing-in-itself could be understood by analogy as the relationship between human will and human body.The idealist philosopher George Berkeley argued that physical objects do not exist independently of the mind that perceives them.