Someone recently tweeted the question of if aliens would be more or less benevolent than us. My first reaction was “how could we possibly know how we differ from aliens?” But on reflection, that was hasty, and it seems that we could productively think about how we may differ from aliens.

If we are talking about aliens that we might meet soon, one big obvious difference is that they’d be far more advanced. Because aliens substantially less advanced than us couldn’t meet anyone. If we are nearly the least advanced creatures who could possibly cause or recognize a meeting, then they are almost surely much more advanced. Also, the rareness of having exactly the same origin time (i.e., date at which one becomes advanced enough to meet) implies that any aliens we meet soon must have had an origin time long before us. Millions of years at least, and perhaps billions of years.

What about aliens that we might meet many millions of years in our future, when we are then far more advanced? Can we predict how they might differ from us then? Our best bet seems to be to predict how their past (relative to then) might have differed from our past, as we at least know many things about our history up to today. And the most interesting such differences in histories would be ones that might more strongly “lock in”, causing differences that persist until that future date.

But how can we predict differences in alien histories? One approach is to look for spectrums where we seem near one end. For example, at some point humans became an “apex predator”, who preyed on other creatures but where no other creatures preyed on them. As this is at the end of a spectrum, we can say that other aliens were either also once an apex predator, or they were not. So we might expect that on average ancestors of aliens were more afraid of being preyed upon than were our ancestors.

A second example is that only 5% of stars are more massive, and thus shorter-lived, than our stars. Which suggests that most aliens might be connected to longer-lived stars than ours. A third example is that political units like nations today are nearly the size of the world, even though they were far smaller in the past. Which suggests that aliens tended to have smaller political units, relative to their worlds.

Of course for any feature where our history seems to differ from possible alternatives, we have to wonder how much success (in the sense of giving rise to an alien civilization that might meet others) could be caused by that feature. For example, maybe big stars are more likely to give rise to life, or give life more metabolism to evolve faster. Maybe predators tend to be smarter, and smarter creatures are more likely to give rise to civilizations. Or maybe the formation of nearly world size political units is a prerequisite for expanding into the universe. The more plausible is a strong selection effect for a feature, the less plausible it is that we can predict how aliens differ on that feature.

Okay, I’ve suggested that it is possible in principle to think productively about this topic, but also that this doesn’t seem easy. But a first task seems relatively easy: just collect candidate lists of features where we seem plausibly different, and where selection effects may not be overwhelming. Seems such a project could even be crowd sourced, via asking many people to contribute suggestions. What do you think world, wanna do this together?

Some places maybe to start: kinds of stars and planets, and more generally over places aliens might be found. Alternate kinds of biospheres. Alternate kinds of smart or social creatures. Alternate structures of civilized societies.