"As a child I was in love with a girl of my own age, who was slightly cross-eyed. The imprint made on my brain by the wayward eyes became so mingled with whatever else had aroused in me the feeling of love that for years afterwards, when I saw a cross-eyed woman, I was more prone to love her than any other, simply for that flaw—all the while not knowing this was the reason. But then I reflected and realized it was a flaw: I am smitten no longer." René Descartes

Why did the French philosopher Descartes love a girl whose pupils migrated toward her nose? Various reasons are proposed and the most powerful one may be the of imperfection-given that a certain degree of (almost) perfection is present as well.

One can explain Descartes's preference by arguing that each of us has a certain flaws; therefore, it is inevitable that we will fall in love with people with some flaws. However, this cannot be the whole explanation, as Descartes later tended to fall in love with other cross-eyed woman. In this sense, he perceived crossed eyes very positively, despite the fact that he knew it was a flaw.

It would appear that when Descartes fell in love with the young girl, he loved her whole , which included other characteristics, but her crossed eyes were the most unique. This feature of the girl distinguished her from most other girls. It is as if he subconsciously thought that every woman who shared that distinctive feature would have the other positive characteristics of the girl with whom he had originally fallen in love and would therefore generate the same profound love. This attitude makes him perceive these women as beautiful.

A distinctive feature catches our and because of the considerable weight we give to it, we sometimes consider it to be also essential to our overall evaluation of other people who share it. However, the fact that the girl he fell in love had the distinctive feature of crossed eyes did not mean that her other characteristics would be shared by other women who have the same feature. In fact, however, this mistaken association set off a feeling of love when he encountered this characteristic in other women. Actually all of us tend to be attracted to someone who looks, speaks, or even has a smell similar to someone we have loved deeply. It is a kind of Pavlovian response which makes us more likely to love this person. It should be emphasized, however, that we actually perceive this person to have more positive characteristics and not merely to be associated with such characteristics.

A somewhat similar mechanism is expressed by the " halo," in which a person, who is perceived as beautiful, is assumed to have other positive characteristics as well. In this case, we may say that Descartes had the "cross-eyed halo:" every woman who had this feature was associated with the girl with whom he had he felt been in love, and so activated a loving attitude which also involved perceiving that woman as attractive.

A somewhat similar phenomenon to that experienced by Descartes is the attraction that some men have for women who wear glasses. Here again, the attraction is for something that expresses a flaw in the sight of the women, but when combined with her other attributes it creates a very positive Gestalt. Eye glasses are often perceived to indicate that the person is educated and even wise. As Christine Whelan argues, men do make passes at women who wear glasses. And while men are attracted to an adorable appearance, they are much more likely to be attracted if that appearance also reveals an underlying and the kind of attributes that has the potential to lead to success.

Various reasons have been suggested as to why men are attracted to women who wear glasses. One is that men once had a desire to have with their teachers (who, according to this theory, are assumed to have worn glasses). Regardless of the specific reason in each particular case, the situation is similar in the sense that a feature that could be regarded as a flaw is evaluated positively in light of past associations related to this feature.

Another relevant consideration is that although perfection and symmetry underlie our perception of beauty and attractiveness, sometimes perfection can be perceived as boring, as being too perfect. In this regard, Megan Slovak notes: "After years of perfection in Hollywood, the backlash has begun! Suddenly we are starting to see a more casual approach to hair and make-up on the red carpet and the runway, and directors and designers are starting to look for the unique rather than the typical, perfect beauty." There are plenty of pictures of actresses flashing tooth-gapped grins, wearing sloppy clothes, or looking with their kids on a day out, all providing examples of the contemporary tendency against over-perfection. Slovak adds that The New York Times reported that "dentists are seeing patients who, instead of seeking the perfect smile, opt instead for slightly stained, overlapping, or grooved veneers. Perfection, it seems, has been exhausted."

People are afraid of being with perfect people. As a woman once said: "If you were perfect, you would frighten me and I don't want that." And author Jeff Riva claims: "I love imperfect characters; both while reading and while writing. Most of the characters I create have some or the other imperfection in them. Imperfection is actually the new perfection. The smudge of Imperfection in characters adds an unexplainable and undefinable appeal... Imperfection makes a character more real." Riva further argues that "though we look up to perfect people, they do give us a temporary sense of insecurity. We feel small in front of them. We may even secretly and subtly resent their perfection... But it's the imperfect characters we bond with. In their presence we revel in our own imperfections... Flaws or imperfection add depth and humanity to the characters. We may say that imperfection is actually the new trend of perfection, but as imperfection increases, its lure decreases."

It should be emphasized that the above claims do not mean that we are not typically attracted to beauty and symmetry. We certainly are. It is simply that when someone is beautiful, the presence of a moderate imperfection, such as cross eyes or eye glasses, might in some cases increase the attraction.

We are indeed typically excited by anything that is incomplete, unsettled, unexplained, or uncertain, as we perceive it to be unusual and so it demands our attention and thoughts. When the situation becomes stable and normal, there is no reason for the mental system to be on the alert and invest further resources. This is usually true of love as well.

Ambiguous and imperfect states, rather than perfect and finished ones, have this kind of incomplete nature and hence offer a certain lure. Resolving ambiguity often eliminates the positive illusion, leading to less satisfying situations. In this sense, the resolution of uncertainty constitutes a negative outcome, which psychologically outweighs a potential positive outcome and therefore can lead on average to worse emotional states (see here). These claims partly explain why courtship, , and extramarital affairs are exciting. All of these experiences are incomplete.

To sum up, it is not obvious which of the above reasons can explain Descartes' love for cross-eyed women. It could be some or all of them. But these reasons indicate that his behavior was not so strange.

The above considerations can be encapsulated in the following statement that a lover might express: "Darling, I know that imperfection can be attractive against the background of too much perfection. But when the imperfections are too dominant, it makes it very hard to love you. But I will certainly keep trying."