Why aren't there multiple species of intelligent life on earth? (yes some animals are pretty smart, but they don't build cars, make movies, have laws, etc.)
Typically, in species without language, it takes many generations for a "mutation"[1] to propagate across the species.
If I instinctually figure out a better way of hunting deer, which gives me an advantage over my competitors for mates, and I pass it on to my children, who pass it on to theirs, etc. eventually the new instinct will be present in most of the species.
(This is basic basic natural selection).
Language changed all of that. Now instead of waiting for offspring to carry a mutation, I can just tell people about the better way of hunting deer, they can do it, and they can tell people too.
Stuff spreads quickly. It makes humans able to evolve at a much, much, much faster rate than any other animal on the planet.
(And yes, really, humans are the only animals on the planet with language. Bird song, whale song, and tree-pheromones don't count.)
[1] In quotes because consciously iterating over a problem (like hunting deer) isn't a "mutation" in the classic sense.
According to who? Neanderthals had the capacity for language, that doesn't mean they used it.
That theory is being steadily debunked. I cannot find the link, but I'm looking for it and as soon as I do, I'll post it - however, a very recent study involved showing dolphins in one aquarium a series of objects and recording the sounds they made when seeing them, then travelling to another aquarium hundreds of miles away, placing the objects in front of the dolphins, and playing back a recording from the earlier round. The dolphins, at a statistically-relevant exceedingly high percentage of the time, would then identify the object the recording was made in response to.
This link was posted in an HN comment maybe 3-4 months ago.
Other animals can communicate in front of each other (bees, elephants, etc.), but the ability to convey arbitrary messages to strangers is, I would say, the very hallmark of a language.
Edit:
Here we go:
* http://wakeup-world.com/2011/11/28/the-discovery-of-dolphin-...
In his bid to “speak dolphin” Jack Kassewitz of SpeakDolphin.com, [...] designed an experiment in which he recorded dolphin echolocation sounds as they reflected off a range of eight submersed objects, including a plastic cube, a toy duck and a flowerpot. He discovered that the reflected sounds actually contain sound pictures and when replayed to the dolphin in the form of a game, the dolphin was able to identify the objects with 86% accuracy, providing evidence that dolphins understand echolocation sounds as pictures. Kassewitz then drove to a different facility and replayed the sound pictures to a dolphin that had not previously experienced them. The second dolphin identified the objects with a similar high success rate, confirming that dolphins possess a sono-pictorial form of communication.
That's the link I was referring to, and as far as I'm concerned, that's enough to treat dolphins as sentient beings.
Another HN link:
* http://current.com/community/91825903_scientists-say-dolphin...
In one study, [...] showed that bottlenose dolphins could recognise themselves in a mirror and use it to inspect various parts of their bodies, an ability that had been thought limited to humans and great apes.
In another, she found that captive animals also had the ability to learn a rudimentary symbol-based language.
[...]
In one recent case, a dolphin rescued from the wild was taught to tail-walk while recuperating for three weeks in a dolphinarium in Australia.
After she was released, scientists were astonished to see the trick spreading among wild dolphins who had learnt it from the former captive.
There are many similar examples, such as the way dolphins living off Western Australia learnt to hold sponges over their snouts to protect themselves when searching for spiny fish on the ocean floor.
Such observations, along with others showing, for example, how dolphins could co-operate with military precision to round up shoals of fish to eat, have prompted questions about the brain structures that must underlie them.
What more do we need to stop being so arrogant as to think ourselves the only creatures on the planet capable of thinking, feeling, remembering, teaching, communicating, and being self-aware?
[1] Metabolically and in other respects; if you doubt this, I've listed what I know about this in http://www.gwern.net/Drug%20heuristics and especially the footnotes & hyperlinks.
I think this is a crucial point. If all of humanity had been wiped out in a famine in Africa fifty thousand years ago, there wouldn't be anyone sitting around today wondering, "Why is it there aren't any civilizations?"
And there were probably millenia that went by when the odds of that happening dwarfed the possibility that we might survive long enough to develop a writing system.
It is only humans that learn from their experience and pass it on. One generation teaches the next one what it learnt. If you sit still for a while and wonder just how we can make such complex things, its because we are building on the knowledge of those that came before us (I think Newton once said "If I have seen farther than others, it is because I have stood on the shoulder of Giants", which was a reference to Galileo, Kepler etc. all of whose work was important for Newton's own discoveries)