In ‘The Later Innis’¹ from 1953, McLuhan described Innis’ social vision in terms reminiscent of quantum mechanics. He compared Innis’ apprehension to an apparatus like a cloud chamber or a radar screen:²

The later Innis had no position. He had become a roving mental eye, an intellectual radar screen, on the alert for objective clues to the inner spirit or core of our times.

…in his later prose the linear development of paragraph perspectives is abandoned almost entirely in favour of the rapid montage of single shots. He juxtaposes one condensed observation with another, mounts one insight or image on another in quick succession to create a sense of the multiple relationships in process… 

What was recorded on that “intellectual radar screen” were “single shots” of momentary traces, momentary lines of force, that illuminated, although never without considerable limitations, some historical epoch. Just as physical nature is the sum product at any instant of time of the interactions of innumerable entities at multiple strata, a sum that is in principle as uncertain as the quantum particles comprising its lowest stratum, so the social scene is such an assemblage of a myriad psychological actions and interactions. Bias, as Innis emphasized, even in the title of his most important book, is of course inevitable in any “shot” recording  a momentary impression of such kaleidoscopic action:

The technique of total presentation or reconstruction led [Innis] swiftly to the vision of the total inter-relatedness of social existence. It is quite evident that Innis was not prepared for all this. No individual can ever be adequate to grappling with the vision of what Siegfried Giedion calls ‘anonymous history’. That is to say, the vision of the significance of the multitude of personal acts and artefacts which constitute the total social process which is human communication or participation [in multiple interacting strata]. For in this kind of awareness ‘commerce’ or ‘technology’ are tools of extremely limited usefulness in discussion. Behind such concepts are the [interactions of a dynamic cloud of]³ human attitudes, preferences and decisions.⁴ 

This notion of the social context or ‘interior landscape’⁵ may somewhat have been prompted by findings in twentieth century physics, but McLuhan was doubtless thinking of Innis for the most part in terms of Finnegans Wake and of “language itself”.

As he put the point simply in ‘The Later Innis’:

Language itself [is] at once the greatest mass medium of communication and also the greatest time-builder of cultures and civilizations.⁶

And in the initial issue of Explorations that year:

Language itself is the greatest of all mass media. The spoken word instantly (…) reverberates with the total history of its own experience with man.⁷

Then again in the same year in ‘James Joyce: Trivial and Quadrivial’:

“Every letter is a godsend,” wrote Joyce. And, much more, every word is an avatar, a revelation, an epiphany. For every word is the product of a complex mental act with a complete learning process involved in it. In this respect words can be regarded not as signs but as existent things, alive with a physical and mental life which is both individual and collective. The conventional meanings of words can thus be used or disregarded by Joyce, who is concentrating on the submerged metaphysical drama which these meanings often tend to overlay. His puns in the Wake are a technique for revealing this submerged drama of language, and Joyce relied on the quirks, “slips,” and freaks of ordinary discourse to evoke the fullness of existence in speech.⁸

Then. finally, early in 1954 in ‘Catholic Humanism and Modern Letters’:

it is a commonplace of the poetic and critical discussion of the last 100 years to note that human languages themselves are the greatest of all works of art beside which the works of Homer, Virgil, Dante, and Shakespeare are minor variations. The English or any other language is itself a massive organization of traditional experience providing a complex view of the world. Today our increasing knowledge of the languages of primitive cultures has made it easy to observe how language itself is the principal channel and view-maker of experience for men everywhere. This reverent attitude to the human world which has unexpectedly sprung up in symbolist, existential and positivistic circles alike is not unrelated to numerous other attitudes and procedures which are common today to the scientist, the historian and the sociologist. 

Although Innis himself had no background or training in contemporary art, this was the context, according to McLuhan, in relation to which he needed to be read:

This prose calls for steady contemplation of what is happening on the page. It is not intended to deliver an idea or a concept in a formula or in a package. It is an ideogrammic prose…

The question of how to conceptualize the interactional social cloud indicated by Innis, and as depicted in Finnegans Wake, would lead McLuhan a few years later to propose the idea of ‘Grammars of Media‘. Innis had been correct to see communication as the key to the comparison and analysis of different cultures, and to have seen media, in turn, from stone engravings to radio waves, as the keys to communication. And he had of course been right to emphasize bias as an unavoidable factor in any sort of intervention in the estimation of such a maze. Now McLuhan submitted that it was necessary to define media not in material terms (“in this kind of awareness (…) technology [is] of extremely limited usefulness”),⁹ but as languages.

Put otherwise — McLuhan twisting Innis’ kaleidoscope — all social phenomena might be seen as linguistic messages through which their enabling media expressed themselves: “the medium is the message”. But in this case, media themselves had to be defined though a specification of their elementary forms and of their laws of combination and interaction. These could be termed their ‘grammars’. And if each medium were a language with its own grammar, the goal of ‘understanding media’ would be to uncover a kind of grammar of those grammars — “grammars of all media in concert”:

Having long been engaged in exploring the characters of the various media of communication, I have become convinced that what is needed is a series of Grammars of the Media. A “grammar of a medium” like English or Latin means a codified awareness of the powers and properties of the medium. And the advantage of such codification is its speed and precision in teaching and imparting the special powers of the medium. (…) The fact of being confronted daily with several media has begun to impress upon observers the strange fact that the medium is itself the message. So that we are beginning to understand why a written message is so very different from the same information when spoken or when pictorialized. (…) Grammars of all media in concert (including the medium of print)¹⁰ are needed, first, to protect and transmit our great stake in the forms and values of the printed word, and equally to foster enlightened use and control of the much more powerful electronic media. An X-ray unit can get very hot but is not a satisfactory space heater.¹¹