I usually have a judgmental reaction when I hear quasi-scientific statements to the effect that “x characteristic evolved IN ORDER TO y”. It’s the same Creator-with-a-Purpose-in-Mind paradigm masquerading as a more impersonal Nature/Evolution-with-a-Purpose-in-Mind. Why doesn’t anyone expose that kind of thinking? It's ubiquitous in popular press and supposedly research-based literature. It’s people with a coat of science over a core of superstition.
But today, I’m going to allow myself just that kind of completely subjective, unscientific and unjustified speculation, which will not increase objective understanding of humanity one iota. It will be more like a rant that’s not rationally founded. (Although I wouldn’t object if anyone can point to scientific research connected with such questions! I’m just too lazy to spend time on research myself. It’s easier to shout out opinions from the bleachers.)
I’m speculating that the “purpose” of sexual attraction in the human species is so that individuals who find themselves in the inexplicable grip of this powerful drive are forced to get beyond the otherwise powerful fear we humans tend to have of the Other, and become physically close enough to perpetuate the species. This might also explain why society conditions us to believe that the most intimate relationships are necessarily our sexual relationships. That only this apparently immense force over which we have no control, can bring two people to get over themselves and allow themselves such intimacy and vulnerability. It’s like those episodes of Star Trek (yes I’m a geek) when the screenwriters wanted to allow their viewers to be voyeurs of a romance between two characters which would otherwise have been unacceptable: they seemed to always invoke some strange mysterious alien force that inhabited the body of this or that person and made them act in a romantic and sexual way towards another crew member, right? So that when it was all over and the alien force departed, we could rest assured, it’s still okay, the fabric of our inhibitions has remained intact, and it’s back to business as usual.
Well as far as I’m concerned, it’s the same thing with non-sexual intimacy. One would think that with our higher faculties we would no longer have to fall back on sexual reflexes if intimacy is what we want. But still we are programmed to believe that we can only be ultimately intimate and vulnerable and real with other people if we are simultaneously sexually attracted to them, and want to have sex with them. It’s as if wanting to be emotionally/physically intimate and completely open is something shameful, and we need a legitimate excuse (our alien force, or in this case sexual attraction) to enact it. As if to say, no, really, I would leave you alone if I had a choice you see, but this attraction thing is forcing me to want to be intimate with you, I’m terribly sorry. As if the only legitimate place in which complete intimacy was allowed, was if there is a sexual contract of couplehood in place; otherwise we have a different contract: to continue to play the game of being afraid of each other and hiding from each other to various degrees, because we are, after all, “just friends”. It’s then tricky and confusing to navigate those waters of expectations. I want more intimacy and at the same time I'm afraid to demolish implicit societal agreements. But it's happening anyway.