The Drake Equation was devised as a way to estimate the probability that there is intelligent life elsewhere in the universe. The probability other civilizations exist is taken to be the product of several factors, many of which were at the time unknown. Here’s the Drake Equation
- N = the number of civilizations in our galaxy near enough to detect
R∗ = the average rate of star formation in our galaxy
- fp = the fraction of those stars that have planets
- ne = the average number of habitable planets per star with planets
- fl = the fraction of habitable planets that develop life
- fi = the fraction of planets with life that develop civilizations
- fc = the fraction of civilizations that emit detectable signals into space
- L = the length of time such civilizations can emit detectable signals
Since we started looking for exoplanets, we’ve gotten some traction on how likely it is that human-habitable planets exist. The other factors are still unknown. Do they develop life, do they develop technological civilizations, how long do the civilizations survive?
What if we’re going about this all wrong?
When I was doing my Ph.D. research project in pattern recognition I came across Watanabe’s Ugly Duckling Theorem. Classification of an object depends on measured characteristics (“predicates”) of an object. If you are not even sure of what the relevant categories are, then the measured characteristics need to determine the list of categories as well.
The Ugly Duckling theorem concerns how you assign importance (“weight”) to the attributes of an object you measure. The theorem states that, if all possible predicates are equally weighted, all objects are members of the same class. To make any progress you need to limit the number of predicates you consider important and weight each one according to its importance in determining both the list of categories and the category to which an individual object belongs. The list of key predicates and their weights constitute your bias. You might think bias is your friend, at least as far as classification goes. But if your bias leads you in the wrong direction then not so much. As so often, the devil is in the details.
What if the whole problem with the Drake equation is that the predicates we use to define intelligent life are the problem, not the solution? If we are biased toward recognizing life as we know it, or recognizing signals we expect, we may miss life that’s outside the boundaries of our imagination. We may fail to consider whether a body we do detect might harbor life even if it would not support us.
This is all a nice intellectual exercise until something alerts us to look where we might not. In the movie Independence Day, the first scene where the characters realize that they’re dealing with an intelligent species is when they notice that the incoming visitor from beyond the solar system is not speeding up as it approaches the Sun – it’s slowing down!
This is the premise of my WiP novel Watanabe’s Hammer. Stay tuned.