I’m wondering if it’s pseudo religious with humans being created in God’s image (Ancient Aliens stuff), the human-centric idea that intelligent life must resemble us, it being easy to make costumes for movies and TV when all you need to do is paint someone’s skin, or if SciFi writers were going for the uncanny valley effect for example.
I think there’s a compelling argument here. Certainly not all aliens would be bipedal tetrapods, but the ones who go on to be tool-using, space-faring species probably would be.
Yeah, that’s my thinking as well, although to be clear, I’m not saying that intelligent life would be humanoid, just that it’s the most reasonable real-world explanation I can come up with for why fictional aliens look human. I’m not an exobiologist, and I have no idea what the leading theories are on what intelligent life might look like. I’m just saying that, whenever I’m watching some sci-fi with a bunch of human-looking aliens, my go-to head cannon to explain it away is Convergent Evolution, and it at least feels like a reasonable explanation.