I can't think of a reason pheromones couldn't be converted into some forms of communication technology and back, if necessary. From Gibson's Neuromancer: THEY sent A SLAMHOUND on Turner's trail in New Delhi, slotted it to his pheromones and the color of his hair.
As various people have already said, humans don't naturally communicate using text, yet we're all doing it right now. In fact, my own ancestors (the original inhabitants of Scotland) got as far as the Bronze Age without ever developing a written language, as did many other equally intelligent early peoples. On the other hand, the ability to communicate without being seen or heard means that we lose quite a lot, in particular the ability to tell whether the other person is lying (for further examples, see... well, basically the entire internet). We're not entirely verbal creatures ourselves. Like other animals, we use all relevant senses to determine how a social interaction is going. Yet in the absence of any senses at all, we can communicate perfectly well via text. An alien species whose language is too illogical to do this probably hasn't figured out mathematics, and therefore has no science beyond maybe Stone Age tech at best. On the other hand, a very intelligent but utterly alien species might be able to communicate very well indeed with humans using technology which will translate their language into sound or text, or if they're not excessively alien, they might be capable of speaking Earth languages directly, and fully understanding what they mean. Yet at the same time, their perception will inevitably be colored by the way they've evolved. For example, a sentient being with full control over the coloration of tiny areas of its skin (squids do this best, though some reptiles are fairly good at it, especially chameleons, who primarily use their color-changing ability to display threats or a desire to mate, not to hide) might have difficulty relating to a human wearing blue clothes because its species turn blue when they're murderously angry. And if green is their mating signal, it might find humans in green clothing horribly obscene. Maybe if their visual displays were complex enough to be a true language, somebody in a tartan kilt and a paisley shirt would be conveying a vile insult and a sublime religious message with different bits of their body (as a Scotsman myself, I'll leave it up to you to decide which is which). It would also have extreme difficulty understanding human racism. Presumably such creatures would consider it very rude to wear clothes, in the same way that in some parts of the world it's illegal to go out in public with your face completely masked. Clothing required for warmth or other reasons would be as transparent as possible, and they'd find it as awkward to wear a bulky, opaque hostile environment suit in order to visit humans on our own planet as we would to strip naked in public. Other senses are literally impossible to imagine accurately because we're limited by our human perceptions. For example, many fish can sense the very weak electromagnetic fields generated by other fish because, if you live in a highly conductive medium like salt water, it's a tremendously useful sense to have. Some of them have even developed these sensory organs to the point where they can generate electric pulses powerful enough to stun a horse. From our point of view, this would be more like hearing than sight, with perhaps an element of hot/cold, since it would be coming at you from all directions. Aliens from a world where for some reason - probably a not very bright sun - sight wasn't as vital as it is to us might have a similar sense. They'd find the uncontrolled electrical body-language of a human completely random and possibly wildly misleading, and our homes full of unshielded electrical apparatus would seem to them a screaming cacophony of gibbering chaos. Oh, and here's a real-life example. Humans devote far more of their brains to sight than they do to any other sense, because we use it by far the most. Other animals allocate their brains in different ways. Dogs, which can see pretty well but not quite as well as you, have far more sensory cortex space devoted to smell than they do to sight. The physical organ giving you the ability to pick up scent is incredibly basic - it relies on the overall area of a patch of tissue up your nose, and whether or not it's scrunched up doesn't matter. It's easily within the capability of medical science right now to make you as sensitive to smell as a bloodhound. But it wouldn't work, because your brain isn't equipped to cope with that type of information any better than it already can - you'd just find every smell so overwhelming powerful that almost immediately you'd start begging them to reverse the operation. Dogs, on the other hand, can deal with it. Know why wolves howl at the Full Moon, especially the Harvest Moon that, even to humans, looks unnaturally big? It's not because they're interested in astronomy. It's because their primary response to anything is to smell it first and look at it second, and suddenly there's this enormous impossible-to-miss thing in the sky that smells of nothing at all. From a human point of view, it's like a loud, continuous noise out of absolutely nowhere, and since dogs are pretty smart, it freaks 'em out. I hope that was helpful.
I disagree with this, and the justification that followed it seems to me more full of holes than the Albert Hall. But it's not important enough to put effort into refuting it. So I'll leave it as an exercise for the interested reader to come up with plausible scenarios that break those chains.
You are proving my point in more ways then you know. For a start, the development in a non audio form of communication was a huge leap for our civilization, and the people that developed it were at a huge advantage throughout history. You see consistent accounts of people with written language kicking the crap out of the illiterate. It's not hard to extrapolate that similar groups of aliens would see a need for audio communication, invent a system, and go on tho beat the shit out of everyone that didn't have that means, until the entire planet was grunting, or snapping, or whatever.
You keep using our civilization as a limiting factor, in contrast to how I mentioned before that this is alien. Therefore you can make a basis on reality, but it leaves you the flexibility of evolving communication mechanisms on their own. Like someone earlier on the thread stated, if we lived over a billion years ago, the anatomical complexity of things like the retina didn't exist. As I said before before, we felt the same about sun/star light and its vitality to life before the 1980s. Chemosynthesis wasn't even taught to classes til after 2005 or so.
Once again I have no idea what your point here is. I'm using our civilization as an example, because it's the only one we know of. But more importantly (as any sociologist or historian will tell you) we have reached this point in our development because of specific and concrete developments in our history. Without these events and inventions civilization fails to progress, and we see this in the underdeveloped peoples of Africa, the Steppes and the New World, the last of which lagged behind Europe by an estimated 20,000 years. We could not have lived a billion years ago. Partly because evolution doesn't work like that, and partly because there wasn't enough oxygen on earth. Are eyes a necessity for evolution? Probably not, alien creatures could use sonar maybe? But then how would they create a system of writing that could easily be transported? That's an incredibly important stage in our development, without which our astronomical goals are set back centuries, if they can ever be realized. Most don't have the cones in their eyes to see the red spectrum, but we do. It's thought that this was developed so the our gatherer ancestors could identify poisonous berries. Do aliens need it? No. But without it spotting the red spectrum shift in the stars isn't possible, so key theories about our universe remain undiscovered. We have only achieved as much a our development has allowed us, and while it might be possible to achieve as much with less, the development time is millennia longer, if it ever happens at all.
I'm loath to recommend homework, but watching the BBC series Connections will really shed some light on the pathway of human development. In particular how small inventions, like the plow, were instrumental in our young civilization.
I don't have the slightest idea what Boddagetta is saying either - it just reads like random word-salad. Yes, a billion years ago, complex organs like eyes hadn't evolved, but since even more complex organs like brains hadn't evolved either, I don't suppose there was very much meaningful communication going on. Jack Asher, can I just point out that the inability to see the color red would have absolutely no effect at all on our understanding of the Universe. We'd call redshift "orangeshift", but we'd be able to detect it perfectly well - I don't think you know how this branch of physics works. Also, a great deal of astronomy involves looking at frequencies of the electromagnetic spectrum that humans cannot directly perceive - infra-red, microwaves, radio, etc. I can't see ultra-violet light, and you can't either, unless you're a bee. But we both know it exists.
Orange is derived from red, at best we would be able to see yellow shift, except we couldn't because the spectrum doesn't work that way. I should amend the above. I don't want to say that key elements are impossible. They just make obstacles to of our evolution nearly insurmountable. Lack of audio communication is one of these, because the development tracks with human evolution and culture in the cement way. Without it wars aren't won, people don't pray, and slews of key points are lost. It's much more likely that a race that didn't evolve with vocal cords or other noise making systems would quickly build them, audio being as integral to the development of civilization as writing is.
