The electric light is pure information. It is a medium without a message, as it were, unless it is used to spell out some verbal ad or name. This fact, characteristic of all media, means that the “content” of any medium is always another medium. The content of writing is speech, just as the written word is the content of print, and print is the content of the telegraph. If it is asked, “What is the content of speech?,” it is necessary to say, “It is an actual process of thought, which is in itself nonverbal.” An abstract painting represents direct manifestation of creative thought processes as they might appear in computer designs.

That the content of writing is speech, and the content of speech, thought, etc. seems fairly self-evident. The bigger jumps here are accepting electric light as “pure information” and abstract painting as a “direct creative thought process” Perhaps a more specific content of electric light, which may or may not have occurred to MM in his own time is “non-virtual-space.” Electric light makes content possible by illuminating space or surfaces that are otherwise not illuminated by the Sun or another source of light. While this is comes pretty close to being the bottom line of “information” it clearly is only important to information that pertains to the eye. Electric light has little bearing on hearing, say. To call it a “medium without a message” sort of goes against his next, more important, point…

What we are considering here, however, are the psychic and social consequences of the designs or patterns as they amplify or accelerate existing processes. For the “message” of any medium or technology is the change of scale or pace or pattern that it introduces into human affairs. The railway did not introduce movement or transportation or wheel or road into human society, but it accelerated and enlarged the scale of previous human functions, creating totally new kinds of cities and new kinds of work and leisure. This happened whether the railway functioned in a tropical or a northern environment and is quite independent of the freight or content of the railway medium.

The “message” then is the effect. As such, the message of electric light is the effect it has on its environment including human affairs. It is not without a message, only it has such a large message(such a large effect on human affairs) that is difficult to see the forest for the trees, at least at this point in history. The railway example is important in that it shows the the effect from a high-level societal perspective. The introduction of railways, like electric light, disrupts the patterns of living of those in its sphere of influence a great deal. As regards the railway system, its effect can be seen a little better than electric light because it is now less ubiquitous. While his use of the terms “medium” and “message” tends to have some range, the phrase “The medium is the message” is essentially a call to pay attention to the effects of the means of conveyance and not only what is conveyed.