The thesis of the book is that
the technology of book printing shaped "a new kind of man".
McLuhan begins by quoting the physician J.C. Carothers. The literate child receives an education that is largely delegated to assorted media and objects, none of which provides an emotional layer, whereas the illiterate child enjoys an education that is almost exclusively based on the spoken word, and that is therefore loaded with emotional meaning. The illerate world is a world of sounds, whereas the literate world becomes a world of written words and visual media in general. Written words translate speech from the realm of sound to the realm of vision, a realm that loses the emotional power of the human voice. McLuhan emphasizes that the eye is neutral, unlike the voice. The voice always contains an additional layer of meaning, that of emotion. McLuhan believes that the phonetic alphabet represented the first step towards this translation of the auditory into the visual, and that another major step took place with the invention of the printing press (manuscript culture was still intensely audio-tactile compared with print culture, which was essentially visual). Alphabetic literacy fostered an intense visual life. Quote: "Mechanical and typographical technology had conferred on the visual great preponderance". The concept is better expressed by Walter Ong: "the use of printing moved the word away from its original association with sound and treated it more and more as a thing in space".
He keeps repeating that the passage from manuscript to print caused people to stop reading aloud and in public; and started the praxis of reading in silence and in private. "Print gradually made reading aloud pointless" But he never proves it. It seems to me that it was literacy, not the printing press, that caused that change in habits. When only a few could read and write, it was natural for them to read to an illiterate public, not only to themselves. Whether the book was a manuscript or a printed book makes no difference.
The invention of the printing press also happened at the time when painters were introducing the perspective space. Illiterate people, who don't know about perspective, use the eye tactually. They don't separate vision, touch and sound. Literate people, trained to use perspective, have a detached point of view and separate sight from touch and sound, a process which was already the very foundation of Euclidean geometry.
McLuhan argues that there is a law of compensation among the senses: "any extension of the sensorium by technological dilation has a quite appreciable effect in setting up new ratios or proportions among all the senses"; "It would seem that the extension of one or another of our senses by mechanical means... can act as a sort of twist for the kaleidoscope of the entire sensorium"; "only great inattention could conceal the role of new media of information in altering the posture and relations of our senses".
McLuhan emphasizes that the printing press was the first case of mechanization of an ancient handicraft and influenced the mechanization of all handicrafts. McLuhan credits the printing press with starting the society of mass production (and therefore of mass consumption) that would slowly but steadily mechanize all human handicrafts.
Quoting the study of Goldschmidt, "Medieval Texts and their first Appearance in Print" (1943), McLuhan argues that printing press created the need for copyrights, a concept that did not exist in the Middle Ages when authors would freely borrow from other authors, when the idea was of a global body of knowledge, shared by all scholars, with no particular need to identify who had said what before the others. Manuscript culture was producer-oriented, Print book culture became consumer-oriented. Producers were interested in using knowledge to produce new knowledge. Consumers, on the other hand, were only interested in using knowledge private authorship McLuhan contradicts himself, though, when he mentions that manuscripts had few readers because few people could read and write. When the printing press started making many copies of a manuscript, it didn't change the fact that the audience was very small. What created the "consumer-oriented" culture was literacy, not the printing press. And, incidentally, what increased the production of books was not the printing press per se, but the "invention" of paper, that replaced the expensive vellum. Again, the limit to the mass production of books was not so much the technology, but the fact that there was no demand for massive amounts of books, since there were very few people who could read them.
Literate people accept the role of passive consumers of books (or films) whereas illiterate people have no such concept. An illiterate audience does not silently without participation. Print is a technology that "decollectivizes man". Quote: "Print is the technology of individualism".
The printing press also led to the adoption of vernacular languages that created a sense of nation that led to nationalism, a phenomenon that did not exist before the Renaissance. Nationalism is actually very unnatural.
The phonetic alphabet and the printing press shaping the human mind for centuries. Euclidean space is a product of literacy, incomprehensible by illiterate minds. The fiction of a flat, straight and uniform space was created by the phonetic alphabet. Infinitesimal calculus was one of the many side-effects of print technology.
McLuhan believes that the interconnectedness of the electrical age returns us to the visual world of the illiterate world. the 20th century strives to free itself from the condition of passivity inherited from the age of the printing press. The electric age is taking humans out of the literate and numerical age, into a "post-literate" age that is breaking free of the constraints of the old literate age.
McLuhan was on his way to resurrecting the concept of the noosphere (that he credits to Pierre Teilhard de Chardin instead of Vernadsky), the global intelligence of human civilization; and he viewed Alexander Pope's poetry as a prophetic vision of its advent: