Half a century ago, Stern discussed this attribute of an artistic object and called it apparency. While art is not limited to this single end, he felt that one of its two basic functions was "to create images which by clarity and harmony of form fulfill the need for vividly comprehensible appearance." In his mind, this was an essential first step toward the expression of inner meaning.
The personal experience of most of us will testify to this persistence of an illusory image long after its inadequacy is conceptually realized. We stare into the jungle and see only the sunlight on the green leaves, but a warning noise tells us that an animal is hidden there. The observer then learns to interpret the scene by singling out "give-away" clues and by reweighting previous signals. The camouflaged animal may now be picked up by the reflection of its eyes. Finally by repeated experience the entire pattern of perception is changed, and the observer need no longer consciously search for give-aways, or add new data to an old framework. They have achieved an image which will operate successfully in the new situation, seeming natural and right. Quite suddenly the hidden animal appears among the leaves, "as plain as day."
Everything points to the conclusion that the phrase 'the language of art' is more than a loose metaphor, that even to describe the visible world in images we need a developed system of schemata.
Learning to design is, first of all, learning to see. Designers see more, and more precisely. This is a blessing and a curse—once we have learned to see design, both good and bad, we cannot un-see. The downside is that the more you learn to see, the more you lose your “common” eye, the eye you design for. This can be frustrating for us designers when we work for a customer with a bad eye and strong opinions. But this is no justification for designer arrogance or eye-rolling. Part of our job is to make the invisible visible, to clearly express what we see, feel and do. You can’t expect to sell what you can’t explain.
This is why excellent designers do not just develop a sharper eye. They try to keep their ability to see things as a customer would. You need a design eye to design, and a non-designer eye to feel what you designed.