McLuhan’s ‘The Aesthetic Moment in Landscape Poetry’ (1951) was reprinted in The Interior Landscape, indicating McLuhan’s evaluation of its importance along his pathway. Here is to be found:

With Joyce words syntactically ordered to statement yielded to words as pantomime, as ballet, and especially as static landscape. Mallarmé, in his Coup de Des, had preceded Joyce in establishing the printed page as a symbolist landscape able to evoke the most ephemeral incident and, simultaneously, the most remote cycles of time. For Mallarmé, as for Joyce, the minutest, as well as the most esoteric, features of the alphabet itself were charged with dramatic significance, so that he used the word and the printed page as do the Chinese, for whom landscape painting is a branch of writing.¹

This was an understanding of print and of time and of their interrelation that would occupy him for the remaining three decades of his life. The printed page as “syntactically ordered (…) statement” could be taken not — or not only! — as the continuous ABCDE unfolding of a lineal message, but also as an ABCEDminded² “static landscape”, or snapshot, in which time itself was figured in it from “the most ephemeral³ incident” to “the most remote cycles of time” and its ground, “simultaneously”. The emerging idea was that print, exactly in its multiple (and by no means only negative) limitations (arbitrarily isolated atomic units configured in serial order and all that this implied for history and consciousness) could be perceived as revealing at the same time an entirely different time-space order (“words as pantomime, as ballet (…) charged with dramatic significance”).

McLuhan had been thinking about the implications of particularity for decades⁴, but now he began to sense, in what amounted to a second conversion, that incarnation had no limit. There was nothing that could not also be beheld as expressing an entirely different order and this relationship between orders was precisely that “inclusive and integral image” to whose specification he had been elected.⁵ Reflecting back to this time around 1951 in his Playboy interview, he recalled:

For many years, until I wrote my first book, The Mechanical Bride, I adopted an extremely moralistic approach to all environmental technology. I loathed machinery, I abominated cities, I equated the Industrial Revolution with original sin and mass media with the Fall. In short, I rejected almost every element of modern life in favor of a Rousseauvian utopianism. But gradually (…) I ceased being a moralist and became a student. As someone committed to literature and the traditions of literacy, I began to study the new environment that imperiled literary values, and I soon realized that [the new media and popular culture] could not be dismissed by moral outrage or pious indignation. Study showed that a totally new approach was required, both to save what deserved saving in our Western heritage and to help man adopt a new survival strategy. (Playboy Interview)

Remarkably, this “totally new approach” did not represent an exclusive break with the past, but a revolutionary accommodation with it that was inclusive. The “totally new” was a reversion or, as McLuhan often put it, a “retracing”, that accorded itself to the light coming through all things including “environmental technology”, “the Industrial Revolution”, “mass media” and  “modern life” in general. In a word, he adopted in regard to the universe of human experience the posture of a proto-chemist who determined to begin studying all materials across all their manifestations and interactions.

A footnote to the passage cited above from ‘The Aesthetic Moment in Landscape Poetry’ and concluding with “landscape painting is a branch of writing”, referred to:

A.C. Moorhouse, Writing and the Alphabet, London, 1946, p. 59.

Presumably McLuhan had found this reference the year before reading Innis’ Empire and Communications .  It appears in a footnote to p 10 of its ‘Introduction’:

See C. L. Becker, Progress and Power (Stanford University, 1936); see also A. C. Moorhouse, Writing and the Alphabet (London, 1946).⁶

Now the year 1951 was of great significance to McLuhan: he turned 40; The Mechanical Bride was finally published; his turn to Joyce was completed as defined that year in his ‘Joyce, Aquinas, and the Poetic Process’; his correspondence with Ezra Pound (backed by his study of the Cantos and of Pound’s critical writings) was flourishing; his relationship with Innis was taking off (only to be cut short by Innis’ early death in 1952); he was beginning to investigate the roles of media in culture as reflected in his letter to Innis from March that year and as detailed in his advanced summary of “the end of the Gutenberg era” in his letter to Pound⁷ in July 1952 (reflecting ideas he had come to, in the main, in 1951).

Moorhouse’s book with its chapter on the Chinese may have been an important marker in this context. Its page 59 referenced by  McLuhan has this extended passage (going over to page 60):

Calligraphy has always been held in the highest esteem in China : indeed, landscape-painting is really to be regarded as a branch of writing, and landscapes often include written texts from poems on account of the beauty of the script as much as for literary reasons. Our alphabet has in comparison a plain and matter-of-fact appearance. But there are more practical reasons [for comparing the two]. The Chinaman who has learnt to read is equally at home with a government notice of to-day and with the literature that reaches back for over three thousand years. The writing is materially the same, though the language is not. Now this is a most peculiar situation. Contrast what happens with a phonetic system of writing. In ancient Greek there is a period of only five or six centuries between Homer and Aristotle, [not the three thousand of the Chinese,] yet the language changed considerably in that time. The student who knew only the Greek of Aristotle would find himself at once in difficulties with that of Homer, in respect of the vocabulary, the sounds and the grammatical forms. His difficulties would all arise out of distinctions in the spoken form of the language: and since the writing is based on the spoken form, and simply reproduces all the distinctions, it can do nothing to remove them. Admittedly Greek is an extreme example, because of its great diversity. We can, however, see a similar result in English. It is impossible for us, without special training, to read and understand Beowulf, or even Chaucer: their language is different, and therefore so is the written form [reflective] of it. The Chinese language [as represented in its script], on the other hand, has not undergone such striking changes (…) [even though] the process of sound change has created a number of modern Chinese dialects, which are sufficiently unlike to prevent the speakers of one of them from readily understanding the others, or the ancient texts, when spoken aloud. This is where the value of Chinese writing makes itself felt, by transcending the speech barriers. Thus the writing allows the Chinaman (if he can read at all) to enjoy the knowledge of his ancient texts — a knowledge which has [practical] significance in Chinese life that is not easy for us to estimate.

Moorhouse brings together writing as “landscape-painting” (script and art), different time dimensions determined by the translucence (or not) of script and art, east and west and the importance of “transcending the speech barriers” to the appropriation of (or by!) culture. All of these (though of course not deriving only from Moorhouse) would be critical to McLuhan in the coming decade (and, in fact, for the rest of his life).

On the same page of Empire and Communications just above his note referencing Moorhouse, Innis formulated one of the most important passages in his book:

The significance of a basic medium to its civilization is difficult to appraise since the means of appraisal are influenced by the [different] media [employed by it, on the one hand, and by us, on the other], and indeed the fact of appraisal appears to be peculiar to certain types of media. A change in the type of medium implies a change in the type of appraisal and hence makes it difficult for one civilization to understand another. (…) The difficulties of appraisal will be evident, particularly in the consideration of time. With the dominance of arithmetic (…)  modern students have accepted the linear measure of time. The dangers of applying this procrustean device in the appraisal of civilizations in which it did not exist illustrate one of numerous problems. The difficulties will be illustrated in part in these six lectures in which time becomes a crucial factor in the organization of material and in which a lecture is [used self-consciously as] a standardized and relatively inefficient method of communication with an emphasis on dogmatic answers rather than eternal questions. I have attempted to meet these problems by using the concept of empire as an indication of the efficiency of communication. It will reflect to an important extent the efficiency of particular media of communication and its possibilities in creating conditions favourable to creative thought. (10)

Here, too, media are brought together with different time dimensions and “type[s] of appraisal”. These, in turn, are seen to give access to, or to block access to, “eternal questions” and “creative thought.” Innis then goes beyond Moorhouse in noting how these considerations reflect back on his own lectures and on the “appraisal” that is possible in them for himself and through them for his audience.

What Innis did not see in Moorhouse, however, was the importance of the introduction into this context of “landscape-painting”. It was precisely this point that McLuhan would emphasize in his programmatic letter to Innis early in 1951:

it was most of all the esthetic discoveries of the symbolists since Rimbaud and Mallarmé (developed in English by Joyce, Eliot, Pound, Lewis and Yeats) which have served to recreate in contemporary consciousness an awareness of the potencies of language [understood in Moorhouse’s broad sense as including script and, therefore, art], such as the Western world has not experienced in 1800 years. (…) The discontinuous juxtaposition of unrelated items (…) created, [Mallarmé] saw, a symbolic landscape of great power and importance. (…) The same symbolist perception applied to cinema showed that the montage of images was basically a return via technology to age-old picture language. Eisenstein’s Film Forum and Film Technique explores the relations between modern developments in the arts and Chinese ideogram, pointing to the common basis of ideogram in modern art, science and technology. (…) From the point of view of the artist however the business of art is no longer the communication of thoughts or feelings which are to be conceptually ordered [like Innis’ “dogmatic answers”], but a direct participation in an experience [of “creative thought” about “eternal questions”]. (…) The fallacy in the Deutsch-Wiener [cybernetics] approach [shared by Innis?] is its failure to understand the techniques and functions of the traditional arts as the essential type[s] of all human communication. (…) Arts here used as providing criteria, techniques of observation, and bodies of recorded, achieved, experience. Points of departure but also return. For example the actual techniques of [McLuhan’s proposed] common study today [between, eg, the physical sciences, social sciences, humanities and artists] seem to me to be of genuine relevance to anybody who wishes to grasp the best in current poetry and music. And vice versa.

Problems of communication, aka of “understanding media”, were implicated, this was to say, both in the best modern art works and in any attempt to restore harmony in the universe of human thought and action.