"Looks are voluntary. But the full revelation of the subject in the face is not, as a rule, voluntary. Smiles are usually involuntary, and "gift smiles," as one might call them, always so. Likewise laughter, to be genuine, must be involuntary--even though laughter is something of which only creatures with intentions, reason, and self-consciousness are capable. The important point is that, while smiling and laughing are movements of the mouth, the whole face is infused by them, so that the subject is revealed in them as "overcome". Laughing and smiling can also be willed, and when they are willed, they have a ghoulish, threatening quality, as when someone laughs cynically, or hides behind a smile. Voluntary laughter is a kind of spiritual armor, with which a person defends himself against a treacherous world by betraying it. Blushes are more like tears than like laughter in that they cannot be intended. Only a rational being can blush, even though nobody can blush voluntarily. Even if, by some trick, you are able to make the blood flow into the surface of your cheeks, this would not be blushing but a kind of deception. And it is the involuntary character of the blush that conveys its meaning, which resides in the fact that it is the other who summons it. Looks directed to the looks of another have an "interrogatory aboutness," so to speak. The person who looks at his companion is also aware that he is on the verge of looking into him. There is an element of overreaching here, which is inherited from the I-You encounter, and which changes the appearance of the human look in the eyes of the person looked at. Blushing is a natural response to this, a recognition that the glance that originated at the horizon where you are has touched the horizon in me."