The invention of the alphabet was one of the crucial steps in the development of sequential reasoning, but it was a complete fluke. The alphabet was not invented by some brilliant Egyptian or Mesopotamian writer seeking a better way to put ideas down on paper. It was not even a logical outgrowth of the Egyptian or Mesopotamian systems. We know that the inventors of the alphabet were likely familiar with the Egyptian system. The speculation is that some Semitic outcast set out to create a writing system for his own language and got carried away with the Egyptian rebus system. That is, instead of trying to build a system of pictures depicting words, he concentrated on the sounds of the words. Lo and behold, there were just a few basic sounds, so he needed a fairly small set of letters to represent the sounds. To write, you simply strung together the letters representing the sounds.
Unfortunately, the early Semitic writing system was closer to what we think of as stenography than writing. It lacked three elements that we consider critical: vowels, breaks between words, and punctuation. Semitic writing was a continuous stream of consonants representing the flow of spoken language. Now, these deficiencies might seem fatal, but in fact the writing system worked, after a fashion. For example, vowels are not the most important components of words, a fact that we make use of whnvr we cntrct wrds to gt shrtr sntncs. Breaks between words are nice, butifyouthinkaboutitmostofthetimeyoucanfigureoutthewordswithoutanybreaksbetweenthem. And punctuation is quite helpful, but in fact was not commonly used until after the printing revolution. Before then, punctuation was considered a crutch for slow readers.
There was a good reason, at least, for not including vowels in the alphabet. The Semitic languages use words that are defined by consonants, and conjugate their words by altering the vowels. For example, the Hebrew root word "QTL" represents the basic concept of killing. "QaTaL" means "he has killed"; "QaToL" means "to kill", and "QToL" means "Kill!". With the vowels changing around so much, it seemed unnecessary to include them in the alphabet.
Whatever the weaknesses of the Semitic writing system, we think that it was first invented somewhere in the neighborhood of the Sinai -- that, at least, is where we find the earliest documents written in the new alphabetic system. The Phoenicians, a Semitic people, were the first society to use alphabetic writing on a regular basis. They spread it around the Mediterranean; the Greeks, Minoans, and Etruscans appear to have gotten their alphabets from the Phoenicians.