Well now, there is one classification of aesthetic beauty, where I do actually prefer a metric based scale to provide the needed range of gauging options for properly defining a "quantity" in an otherwise wholly subjective field of measurement.
The beauty of any given woman is truly in the eye of the beholder, and yet we crass male types are always given to comparisons of that which cannot readily be compared. I often find myself having to push the scale when viewing a series of really attractive woman, because three back I already awarded a 10, and yet I find another to seem yet a bit better, so I end up breaking the scale to award 14's and the like. Clearly the standard scale of 1 to 10 is not adequate to the requirements of the field of application.
Thus a new scale needs be created that offers far greater range, and more options, to score near equals with nuanced grading so that they may be very near each other yet still have a slightly different rating assigned to each of them.
Going back into deep history I find a perfectly usable standard of beauty to base the new system upon, and a simple base 10 decimal system, exactly like the metric system provides, is perfect for this scale expansion that I wish to employ.
So here's the new deal .... as it were. In ancient Greece, somewhere around the turn of the 1200 century BC, a woman named "Helen" the wife of Menelaus the King of Sparta, who was then considered the most beautiful woman in the world, either absconded on her own, or was absconded with by Paris, the King of Troy, thus fomenting the Trojan Wars of great and historic renown. Her husband then proceeded to launch a thousand ships to attack Troy and effect the return of his beautiful Helen. Or so goes the history/mythology of the events according to Homer ..... but enough of that seminal digression.
Let us now define this new scale of feminine beauty which I propose, based on the Helen scale:
If Helen possessed such a beautiful face as to be the cause of launching 1000 ship, then in a metric format, a woman with a face that would launch only 1 ship would score 1 millihelen. Ergo 1/1000 of a Helen is one millihelen or 1mh! Thus we now have vastly (or perhaps only half-vastly) expanded upon the old and inadequate "Bo Derek" scale, by a factor of 100, and may now more closely define the beauty that we see, as we see it!!!
If you doubt that there are women whose beauty would only launch but a single vessel, would ever get any vessel launched in their name, I suggest you look to the naming of New England fishing schooners of a century and more past. Many were the schooners, which bore the owner/captain's wife's name, and often when photos of these women are found, it becomes more obvious why their men might be willing to go out fishing on the "Banks" in mid-winter risking everything, life itself, in miserable conditions for long periods of storm, ice and privation ..... just to get away! Perhaps in some cases anyway .... but I digressed yet again, to no point in this instance, so I'll desist.
Please feel free to use this system of subjective comparison if you wish ...... or not, but I do find that it offers far more scope than the old system currently in use.
;c)