Helen Fisher reports that "there is a lower rate of divorce in people who met online dating". I was not surprised to hear that; it is way easier to buy that exact thing you seek through eBay than to browse local markets and individual stores. The same ought to go for finding people.

The above observation is not going to feature in a romantic comedy film any time soon. A romantic story tends to be local in time (e.g. Your Place or Mine), or local in people, (e.g. Same Time Next Year), and usually both. I start wondering if there are other benefits of online dating that will not be portrayed in film?

Ms Fisher also says "you learn a lot between the sheets." I have certainly learnt a lot doing this online dating thing, but less between the sheets than not. I have mostly learnt things about myself.

Let me backtrack a little. There is a degree of consensus among [decently qualified] relationship advisors that "the five things people want are respect, trust, laughter, making time for the other, and physical attraction." While this may be true emotionally, it is seriously incomplete.
Are there demands around fidelity (meaning intent to sustain LTR), monogamy, cohabitation, marriage, financial support, children and so forth? What exactly do you need to guarantee physical attraction? The demands can be discussed, although I have been surprised by the number of ladies I meet who do not bring these subjects up. Statistics say that most (under-40, US-based) couples only discuss where their relationship is going around the third month. I am careful to announce early on that I am not looking for marriage.

As for physical attraction, 'chemistry' as it is often termed, this is a wicked problem. I have summarised what I have learnt about whatever attracts me in Something's Gotta Give. Mostly I have identified things that are not important (height, width, ethnicity, hair colour, occupation, etc). I have to believe that chemistry is governed by evolved biology; for me much of it is in appearance, with later contributions from voice, smell, and movement.

I seem to be the conspicuous opposite of people portrayed in Materialists, but that is a seriously unrealistic story, I hope!

A difficult experiment to explain with any theory is the success rate of arranged marriages. Apparently chemistry can grow with time, or is it that partnerships can last without chemistry? A friend was in a legally-sexless marriage for more than 40 years, so I suspect it is the latter. That feels like sticking on 17 points in a game of 21 (Blackjack).

A method for exploring chemistry is to consider what "standard images" appeal. This is similar to identifying a colour using a book of Pantone colours. Movies, or at least popular actresses through their movies, provide a bunch of standard templates that cover appearance and (when you view their films) movement and voice. I find Angelina Jolie, Sophia Loren, Liv Tyler, Ava Gardner, and Michelle Pfeiffer attractive, but not so much Reese Witherspoon, Jennifer Lawrence, Kim Novak, Rita Hayworth, Jennifer Aniston, Rachel Brosnahan, or Jennifer Connelly. Some women I find 'glamorous' (e.g., Audrey Hepburn), others 'voluptuous' (e.g., Lauren Bacall). As 75-year old ladies go, Helen Fisher in the image above right seems very attractive to me, more so when you see and hear the moving version. I seriously disagree with most rankings of attractive actresses, but then I assume most guys would... the whole game is inscrutably personal, and 'beautiful' too vague and one-dimensional.

In complex number theory, simple comparison is not defined. One can only rank complex numbers by ranking their absolute values. Having the ranking does not help you identify the original numbers. It seems to me that chemistry is hypercomplex. I have too small a dataset to resolve even the dimensionality.

I wish I had a solid and useful conclusion to offer in this essay. I had more useful conclusions in The Secretary Problem working with the absolute value of this thing called chemistry. Nevertheless, I feel happier the more I learn, and more confident in dating.

Diary entry: Having passed the 37% point, the algorithm seemed to have worked brilliantly. Sadly secretary A refused the job offer. Need to increase the flux.