It could be the secret that Mankind has been searching for all these years - the ultimate key to understanding physical attraction.
I know this guy, The Younger Dr P (junior sibling of my oldest friend, The Egregious Dr P), an eye specialist, who has hatched this theory that the most important component of attractiveness (at least in women.... at least in women that he fancies) is the IPD. That's the Inter-Pupillary Distance, the space between the centre of your left eye and the centre of your right.
Now, of course, we all know that proportion is a crucial element of aesthetics. So, I had initially supposed that the good doctor's theory would be based on identifying an ideal ratio between the IPD and the width of the face, or the width of the eye, or the height of the forehead (or some complex and subtle combination of these measurements, and perhaps others too).
"No!" he corrected me, with a 'mad scientist' gleam in his eye. "It's a constant."
He has a figure in mind, a precise number of millimetres between the centres of the pupils that corresponds to perfect pulchritude. I think he told me what it was once, but I can't now recall. It's probably just as well: such potent knowledge should be kept from the general public - or we'd all be going around with calipers in our pockets, ready to size up potential dates on the basis of exactly how far apart their eyes were.
I confess, I am more than a little sceptical of the doctor's conclusion. I suspect that he has merely found that there is a consistent IPD to which he is attracted; and that this just happens to conform to a certain size of woman and size of face that he is also attracted to, so the proportionality is also perfect. I have fancied women of many different shapes, heights, and head sizes, and I'm sure some of them would have looked, well, funny, if they'd all had the exact same IPD.
Furthermore, I doubt if this can be an objective truth. If there is value in the 'constant IPD' theory of attractiveness, I think it must be in recognising that there is an ideal IPD for each of us (perhaps the same as our own? or do we like girls whose eyes are slightly closer together than ours?), rather than that there's a single standard for the whole of humanity.
It's an intriguing notion, though, eh?
And I can find some consolation in it: Madame X's eyes, alas, are set just a little wider apart than I really care for (although I think it's a matter of proportion, rather than absolute distance). I must try to focus on this fact. Despite managing (almost) to go cold turkey on her since the start of the year, I find that 6 months on I have still not quite shaken off my unfortunate fixation. Sigh.