Searching for a partner-in-life is a lot like SETI, except there are a whole lot of Wow! signals.
In the first place, it’s a big universe, and there are a lot of stars out there. And it’s likely that somewhere in all that vastness, among or below those countless stars, there’s someone else who looks up at them rather like you do. So there’s hope. SETI is not a dead-end road.
But at the same time, it’s important to remember that the distances are large, and that you can expect it to take a long time to find anything. In fact, it’s difficult even to guess at how long it might be, because the factors that influence it are so variable. It could be quite a while, though, and so since we didn’t stumble across the United Federation of Planets in the first little while after we switched on the radio telescopes, there’s an important operating principle we must adopt: to accept that the search may take an indefinitely long time. We could bump into a Golden Record from Alpha Centauri next week, or we could still be looking a thousand years from now, even if we develop spectacular new technologies. It’s no reason to give up hope — as we said at the outset, it’s a big universe — but the realities of cosmic geography make the expected mean time to contact long. So we can’t depend on it.
For the forseeable future, we must accept that it’s just us here, no matter who may be just around the corner in the stellar neighborhood. We can’t hope that contact with aliens will happen soon, and give us the dose of perspective we need to get over our resource wars, our loyalty to man-made economic systems, our religious differences, or anything else we struggle with. This is our house, and it’s entirely up to us. We all live here, and nobody else is going to come save us, so we’d better get our lives in order and learn to get along. We can’t sit around waiting for the Vulcans to descend from the sky and say “You complete me.” We need to be able to live on our own in steady-state.
Which isn’t to say that we give up looking for companions in the cosmos. It’s still a very interesting question, and one of the many things about the universe that’s worth paying attention to and studying. And wouldn’t it be great if we did find someone to understand, someone with a history and home to be discovered, with whom humanity might hope to share a common future? It’d be one of the big developments in that history. But we have to be able to live without it and, while still scanning the sky, not feel broken or empty for its absence. To wonder at all the other things our telescopes detect while accepting that we haven’t discovered any genuine sputniki.
And as it goes for seeking other life in the universe, so it goes for seeking another to share your life. Before you start to scan around for potential candidates, it’s possible to imagine that it’s certain that they exist, or that it’s impossible to ever really find them. But it’s not hopeless, and even before conjecturing about their nature or location, we can set up an expression for the frequency of their occurrence, which gives us an idea how long we should expect to be looking:
P is the accessible population. It could be the whole of humanity, or just the residents of your village, depending on your disposition.
ft is the target fraction. If you’re a man interested in women, this is probably a little over half the population, or roughly 0.51. If you’re bisexual, it’s ~1.
fo is the orientation fraction. Of your target, which fraction have a suitable sexual orientation for you? This is where we have to guess at the incidence of homosexuality (h) and bisexuality (b); for straight people the number is going to be (1-hopposite); for bisexuals, (0.5)*[(1-hopposite)+(hsame+bsame)]. For gays it’s just (h+b), which we’ll assign the value (q). The distinction between hopposite and hsame is in case the incidence of homo- or bisexuality isn’t the same in both genders. For those theories of sexuality that posit a fluid spectrum in place of the three categories I’ve listed, or that suppose people can move between categories with time, this calculation can still be used if you treat it as an effective orientation fraction. That is, regardless of actual or percieved orientation of an individual, what are their habits, in practice, at the moment. This can be difficult to determine, but, then, so is the incidence of homosexuality to begin with.
fc is the out fraction. Of the people in your target gender and orientation, how many of them are open enough about their sexuality to engage in a relationship of the sort you’re hoping for? For straight people in our culture this value is equal to or very close to 1. For gays the value is lower and of uncertain value. Bisexuals, keep applying a weighting formula of the form used in the orientation fraction.
A is the age band filter. Of the population in your area, what fraction are within the realistic age range for the sort of relationship proposed?
R is a final filter for any other personal discrimination; you maybe choose to reject certain segments of the population. Maybe you’ll only go for people who want children, for example.
Note that N is just the total number of potential candidates. We haven’t begun to look at personality, which is once again difficult to quantify. In fact, it’s probably not a question of yes/no, but of a distribution of the sort you get between two interacting fields. And it’s fluid, and personal. This part’s all up to you, and you choose which sort of fish you’re trying to catch, or, another way, which species in the solution you’re highly reactive with. This calculation just determines the size of the pond, the molarity of the mixture.
As well, your personal habits may change how likely you are to encounter potential mates; what sort of people you hang out with or work with, how outgoing you are, what activities you take part in. The likelihood of you detecting potential mates depends on whether you’re the straight guy working in a female-dominated field like nursing, or a male-dominated one like bush flying. Do you keep to yourself, or are you very involved in public community activities? And so on, for a variety of dimensions.
On top of that, the calculation doesn’t account for the fraction of people that are off the market due to being already in a relationship (or by choosing not to look for one). The calculation is meant to represent the long-term possibility of finding a mate; people tend to move in and out of the single category over long periods, so a realistic look includes all potential candidates. In the very short term, P shrinks down to be the set of people you already know, and most of the relationship statuses of those people aren’t likely to change immediately, including your own, so it doesn’t make much sense to worry about statistical calculations. You can just identify the people in your immediate environment that might suit.
But, probably there is a fraction of people who are more or less permamently out of the market, so if desired, the equation could be extended to include a Singleness Factor (S), as well as a Detection Probability (D), and a complicatedly-derived and very personal Compatibility Factor (C), whose calculation is beyond the scope of this writing:
So there’s the stack of factors. Call it the Duck and Drake Equation, if you like. Using it, it should be easy to estimate both the time expected to find somebody, and probability of eventual success, as well as the mean time between hits. Of course, it’s not easy, because the values of so many of those factors are not only difficult to estimate, but fluid and contentious. But it’s a starting point, and a way to consider things. For example, with all these factors, you might imagine that the probability seems pretty small of finding a mate. But the fact remains that most people eventually do, and in fact in most cases it’s not when they’re 70 years old and have been looking for decades. The likelihood is, integrating this function (N) over the whole poulation, that most people do find a suitable mate in the medium term.
What the equation can do, though, is remind us of the factors that influence (N/P), and of the ways we can work with it. It also gives us an idea of the relative mean search times for different individuals. The outgoing, adaptable bisexual or hetero in a queer-friendly society who’s not very fussy about age has the best chance, while the closeted, fussy, gay hermit in the small sharia-bound town can expect, on average, to wait longer. But it’s important to remember that these estimations are statistical. Anybody could meet someone new tomorrow, and even someone whose N/P fraction is very high might end up looking for a long time. This is not a demonstration of a deterministic process.
Even more, particularly for those expecting long mean search times or very short ones, it’s important to remember the First Lesson of SETI: the residents of earth have to be able to sort themselves out on their own. This is a valuable mantra for those who want to be able to live full and vibrant lives while knowing that forming a relationship will be a long-range thing. It’s also important for those with very short mean times; you risk becoming someone who leaps from relationship to relationship and doesn’t develop an independent persona of your own.
In fact, it holds for everyone, regardless of whether you’ve found a mate, or haven’t, or even if you don’t intend to. Mate or no mate, it’s up to you, not someone else, to improve your life and make your short time in this world everything it can be. Don’t depend on someone else to make you whole; if you find a mate, you’ll be leaning on them for what you’ve got the ability to produce, and if you don’t, you’ll languish in despair at feeling cheated by the universe. Work, think, be: take charge of your life and make it something complete for yourself; and if you find someobdy else, so much the better. It’s your life. Sort out how to live it for yourself.
And keep your eyes on the stars.
Peter Backus of London, UK, has also considered this problem (it’s a popular one). His analysis includes a numerical solution for a particular case of interest to him, and was featured on the 13 January 02010 edition of CBC’s As It Happens. It can be found here.
This post is a re-run of text that has been hosted on this site at a variety of addresses since 2006, now integrated into the latest database structure of the site.