In (at least) one of Iain Banks’ Culture books, he says that technological progress is not a ladder, but a rock face. The tech which a species develops depends a lot on the conditions of their evolution, and encountering wildly different techs that seem miraculous or incomprehensible to one’s own species is fairly common.

I think of “intelligence” in a similar vein. We can recognize it when it’s close enough in proximity to the path we humans have taken. The further away another species is from that, the less we are able to recognize/judge their level of intelligence. I like this metaphor because it emphasizes the limits of our own abilities to understand vey foreign things. That’s not to say that we could never get better at it, but there will almost certainly always be more outside of our circle of understanding than inside it.

I’m also reminded of the drunk searching for his house key beneath a street light. It’s not where he dropped the key, but he’s searching there because “that’s where the light is.”