There's a running joke that it's easy to thrive on Tinder. After all, there's only two rules:

  • Be attractive
  • Don't be unattractive.

Hilarious, even if you're homely, but deeper than it appears.

Many people view attractiveness through a dating lens: it's when the people whose pants you want to get into also want to get into yours. When that happens, you're attractive. When it doesn't, you're not.

Some people get hung up on thinking that attractiveness is mostly about a pretty face and a fit body. Those are obvious factors, sure, but far from the entire package. Anyone knee deep in the dating scene understands that stylishness, a quick wit, connectedness, wealth, fame, adventurousness, and so on are also major factors in landing the trophy fish you're looking for.

With so many factors, it's clear that attractiveness is a broad topic. But how broad? When we pull back from the dating lens to take in the whole picture, attractiveness becomes the aggregate effect that you have on other people. While we may be often confused about exactly attractiveness is, if we view it as effect instead, suddenly we can measure it objectively.

A Patek Philippe on your wrist produces a vastly greater effect than a Timex due to its shininess, its high cost, and its reputation. People tend to think more about you, and think better of you, when you wear one. A full-sleeve tattoo produces a similar, though lesser effect compared to a bare arm. A Patek Philippe and a full sleeve? Obviously a baller.

This year's fashion produces a greater effect due to its freshness than last year's. Fashion from fifty years ago also produces a greater effect than last year's fashion, simply due to being unusual. Both together? That's someone you want to get to know better.

Effect is simply a transfer of energy that's subject to the usual laws of physics, much like how the sun radiates heat toward Earth. Any transfer of energy results in a change of some kind on the receiving end. That's how we have life.

We humans know we've had an effect when we see that we've modified the choices other people make in the future. In a purely physical sense, energy from us literally entered their brain via eyes, ears, nose, or otherwise and bounced around long enough to make a difference in their future choices.

The more people whose choices we have influenced, and the greater commitment to those choices, the more effective we are:

  • Effective salespeople crank up the probability that clients will commit to buy.
  • Effective politicians crank up the probability that people will vote for them. Also that other politicians and power-brokers will commit to deals with them.
  • Effective actors get people to drive to the cinema to watch their movie.
  • Effective singles crank up the probability that the type of people whose pants they'd love to get into will notice them and find them appealing.

All of these scenarios are measurable: $20 million in sales, 54% of the vote, $100 million opening weekend, dates with pro athletes or Instagram models, and so on. Because we're in a physical universe, all scenarios are measurable, although we never have complete information.

It's an old idea that humans are irrational most of the time: first we make the decision and afterward we rationalize it. That's perfectly sensible, but what is the principle our brain uses to make these decisions that happen before we realize they've happened?

The principle underlying every decision is quite simple: will I generate more aggregate effect, or less, over the time scales I care about? If more, do it. If less, don't. In other words, will I be more attractive or less attractive? If more, do it (or do something with an even bigger effect). If less, do something else.

It's not a conscious process. Our brains do it automatically for us, continuously. Our lower brain crunches the numbers and directs us to the appropriate choice, followed by our higher brain doing its best to make us feel in control, and to project that feeling onto other people (for even greater effect).

By now you might be wondering why we're all performing this attractiveness dance all day every day, whether we want to or not. The answer is that our very existence depends on it. It's a matter of survival.

Everything which exists has an effect on something else which exists. The greater the effect, the higher the probability of continued existence.

While we might think of great effect being linked to hugeness, great effect is also accomplished via moderate effect over long periods of time. A one-hit wonder like Vanilla Ice, while impressive for a few months before tailing off into punchline territory, adds up to much less than the Rolling Stones or U2 who grind away globally for decades. Yet their aggregate effect is relatively moderate compared to the societal shifts produced by Charles Babbage with his mechanical computer (or if you prefer, the Jacquard loom) or Nikola Tesla with his Alternating Current-based inventions.

Each day you exist, the effect you produced that day is added to your total. Even past your death, your total effect can grow much larger than what you achieved while alive if your ideas continue to spread and influence the choices of other people. This is our legacy.

It might be more clear now that sex itself is based on the degree of one's effect on other people, which we tend to call attractiveness and also call power, dominance, or intelligence. A person who has managed to produce a significant effect (however they did it) has burrowed into the minds of a wide variety of potential mates, some of whom will now have positive thoughts about them and put themselves in closer proximity. It's a positive signal in itself that another person has entered your mind, no matter the details.

When we view this phenomena from the lens of evolution, we see that all animals are engaging in the same basic behavior. A sexual animal who isn't able to get in front of others of their species simply will not reproduce. The ones who get in front more often and produce more effect while there are the ones who will mate more frequently. The details don't matter. So we mate to produce the highest probability of future effect by selecting those who have already proven their ability to produce effect. Making it all about survival.

With the Internet, television, movies and so on, we humans can broadcast our effect to people we've never met before and who would otherwise be unavailable to us. Other animals need physical proximity.

And so, the running joke about Tinder tells us all we need to know about sex, evolution, human behavior, animal behavior, and perhaps the universe itself. Making sense of humanity becomes much easier when we truly grasp this fundamental, inescapable principle which is the basis of our existence and our brain's core function.