Because with a small amount of your own energy as input, you unlock vast amounts of potential chemical energy. No other tool used by other animals comes anywhere close in terms of efficiency. And no other animal is anywhere near as "civilized" (loaded term, I know) as humans are.
It is clear there is something different between humans and all other animals. And one obvious difference is mastery of fire.
> Maybe the criterion 'spend a lot of effort to create a tool' is the criterion, since having the time to spend on tool making requires someone else to get food for you etc.
Which would probably never have occurred in humans without mastery of fire. I think that mastery of fire is the common precursor of any trait you could point to as the defining feature of civilization.
Now it's possible we will find unambiguous traits of "civilization" among some other species that hasn't mastered fire (whether here on Earth or elsewhere), but until then I do believe that it is a prerequisite.
I don’t remember exactly where I read it (might have been here), but Margaret Mead is quoted as saying that the earliest sign of civilization, was a long-healed femoral fracture, in an ancient skeleton. In nature, that kind of injury is a death sentence. It meant that the injured person was taken care of, long enough to heal.
Maybe we’ll find fossils, with healed “death sentence” injuries.
If anyone had ever read Lovecraft’s The Mountains of Madness, he posited a different theory about Cretaceous civilizations.
I'd take this with a grain of Silurian Salt, but there is some fossil evidence that a Tyrannosaurus Rex or two healed from injuries significant enough that surviving them would almost require help from somebody.
The fossil of Barbara[0] "shows a particularly bad break, which goes right through the site of the tendon attachment, so most probably the tendon would have been torn off the bone [...]" If you're a very large two-legged creature a break like that could be a death sentence, but the fossilized break shows signs of healing.
Sue[1] is one of the most famous T. Rex fossils and she shows many healed injuries including broken bones and bacterial infections. It's highly possible that her species is just incredibly tough, but it's also possible that they took care of each other to some degree.
It is clear there is something different between humans and all other animals. And one obvious difference is mastery of fire.
> Maybe the criterion 'spend a lot of effort to create a tool' is the criterion, since having the time to spend on tool making requires someone else to get food for you etc.
Which would probably never have occurred in humans without mastery of fire. I think that mastery of fire is the common precursor of any trait you could point to as the defining feature of civilization.
Now it's possible we will find unambiguous traits of "civilization" among some other species that hasn't mastered fire (whether here on Earth or elsewhere), but until then I do believe that it is a prerequisite.