|Origins of Writing Systems|
Among many ancient societies, writing held a extremely special and important role. Often writing is so revered that myths and deities were drawn up to explain its divine origin.
In ancient Egypt, for example, the invention of writing is attributed to the god Thoth (Dhwty in Egyptian), who was not only the scribe and historian of the gods but also kept the calendar and invented art and science. In some Egyptian myths, Thoth is also portrayed as the creator of speech and possessing the power to transform speech into material objects. This ties in closely with the Egyptian belief that in order for a person to achieve immortality his or her name must be spoken or inscribed somewhere forever.
In Mesopotamia, among the Sumerians the god Enlil was the creator of writing. Later during Assyrian, and Babylonian periods, the god Nabu was credited as the inventor of writing and scribe of the gods. And similar to Thoth, Mesopotamian scribal gods also exhibit the power of creation via divine speech.
Among the Maya, the supreme deity Itzamna was a shaman and sorceror as well as the creator of the world. (In fact, the root of his name, "itz", can be roughly translated as "magical substance, usually secreted by some object, that sustains the gods"). Itzamna was also responsible for the creation of writing and time-keeping. Strangely enough, though, Itzamna isn't a scribal god. This duty falls on usually a pair of monkey gods as depicted on many Maya pots and is also preserved in the highland Maya epic "Popol Vuh". Still, in one rare case, the scribe is a "rabbit".
In China, the invention of writing was not attributed to a deity but instead to a ancient sage named Ts'ang Chieh, who was a minister in the court of the legendary Huang Ti (Yellow Emperor). While not divine, this invention occurred in mythological times, and served as a communication tool between heaven (realm of gods and ancestors) and earth (realm of humans), as demonstrated by the inscribed oracle bones used for divination during historical times.
Whether as a medium to communicate with the gods, or as a magical or supernatural power, writing cleared possesed a divine nature in these ancient cultures. Hence, writing became not only a way to extend memory but also a tool for the elite to justify their rule upon the common, illiterate people.
Jumping ahead in time to the 19th century, we come to a time when social sciences went askew. Overzealous and Eurocentric (I'm using euphemisms here), scholars held that writing was invented only once in Mesopotamia, and all subsequent writing systems were offshoot of this original. They claim that Chinese and Indus writing were evolved from Middle Eastern prototypes, and they completely treated Maya not as a writing system but as a purely calendrical and mnemonic system.
Worse is the fact that they started to abuse Charles Darwin's theory of evolution. They separate writing systems into functional types, which is still valid and scientific. However, they assigned "evolved-ness" to each group, with alphabet being the most evolved, and inherently the best system. Logographic systems like Chinese are considered primitive, archaic, and much inferior, and syllabic systems fall somewhere in between. Their rationale is that alphabets have a small number of signs (easy on your memory) and allow the writer to specify every phonetic value in the language down to the most minute detail.
The biggest problem with the monogenesis of writing system and its subsequence diffusion is obviously that of culturally tinted views. It easily placed Europe as the pinnacle of civilization, relegated the rest of the world to the "primitive" and "unevolved" nature of all other continents of the world, and helped to justify Europe's imperialistic age.
This theory started to break down when the evidence for the indigenous origin of Chinese became very strong with the discovery of the oracle bones and the lack of any earlier text in the vast space between the Iranian plateau and the Yellow River. Another blow was the decipherment of Maya hieroglyphs which revealed a writing system just as sophisticated as anyone found in the Old World. The stage is set for a modern view of how writing came about.
Modern Day Views
Nowadays there is more-or-less consensus on a few points concerning the origin of writing. First of all, writing was invented independently in at least three places, Mesopotamia, China, and Mesoamerica. Recent discoveries might also provide evidence that writing was invented in Egypt and Indus independently of Mesopotamia.
Furthermore, the concept of "evolved-ness" prevalent in the monogenesis theory is refuted in the modern view. No type of writing system is superior or inferior to another, as the type is often dependent on the language they represent. For example, the syllabary works perfectly fine in Japanese because it can reproduce all Japanese words, but it wouldn't work with English because the English language has a lot of consonant clusters that a syllabary will have trouble to spell out. The pretense that the alphabet is more "efficient" is also flawed. Yes, the number of letters is smaller, but when you read a sentence in English, do you really spell individual letters to form a word? The answer is no. You scan the entire word as if it is a logogram.
And finally, writing system is not a marker of civilization. There are many major urban cultures in the world did not employ writing such as the Andean cultures (Moche, Chimu, Inca, etc), but that didn't prevent them from building impressive states and empires whose complexity rivals those in Old World.