McLuhan as a Thomist - some notes

First posted August 10, 1999 - a work in progress! Last updated August 24, 1999

This collection of notes is a response to some readers who cannot find other material showing the influence of Thomas Aquinas on Marshall McLuhan. This page will be constantly updated, and I expect it to be unfinished for quite a time, so check it out periodically.
For Greek citations I use the Windows "symbol" font, and for those who do not have this, a little guesswork may be required. My apologies.

Prefatory Remarks

Many regard the thought of Marshall McLuhan as eclectic and inaccessible. He wrote aphoristically and was not averse to using puns. In some cases, his work is like a Rorschau test. The reader encounters undefined terms and must fill in the gaps himself.

The gist of McLuhan's thought is perhaps summed up in his aphorism: "the medium is the message". The medium of communication, regardless of the content, has its own effect upon our psyche. The use of books creates a certain sort of personality, and from this a certain sort of culture and political order, no matter what the actual content of the books may be. The telegraph, the radio, television, and now the Internet, all create new cultures. McLuhan also pointed out that the effects of the media are all but invisible, since we are immersed in them like a fish in water. A fish does not know what water is until he is beached. Because they are invisible, it is all the more important that we study the effects of the media.

My interest in the thought of Marshall McLuhan was first aroused by two professors at St. Jerome's College, Dr. Gerry Campbell who worked McLuhan's thought into his course of introduction to philosophy, which was basically the thought of St. Thomas, and Dr. Donald DeMarco. Of course, as a Canadian, it was impossible even for a child not to be immersed in the thought and aphorisms of McLuhan during the 1960s and 1970s.

Many years later, I had the good fortune to make the acquaintance of Joseph Keogh at Niagara University. Professor Keogh was Marshall McLuhan's assistant for several years. He passed me an article by Brigid Elson, called "In Defence of the Human Person - The Christian Humanism of Marshall McLuhan" published in the Canadian Catholic Review of Mary 1994. Elson's article makes the point that "Thomistic philosophy eventually provided him with the necessary categories for handling form, cause and effect, and change." Joe Keogh also introduced me to Bruce Powers, Professor Emeritus at Niagara University, and co-author with McLuhan of "The Global Village". Dr. Powers was very generous in his time, in explaining difficult points in that same book.

Formal Causality

The philosophical tradition of Aristotle and Aquinas identifies four varieties of causes: the efficient cause, the formal cause, the final cause, and the material cause. Today, when we speak of cause it is of efficient cause, the agent who does something to effect a change. This is sometimes confused with material cause, as the scientific tendency to present things in terms of their component parts, and treat this presentation as an explanation. The formal cause is more elusive to the modern mind, possibly due to an environment saturated by nominalism. According to nominalism, at the risk of oversimplification, there are no intelligible forms of things, but only measurements, shapes and weights and the like, and the forms that are signified by generic names such as "dog", "lily" and so forth are just convenient handles for certain somewhat similar patterns or arrangements.

This appeals to the modern mind, because we respect the physical sciences above all, and so we admire precision. Quantities can be precisely signified. However, although everyone knows a dog when they see one, no one can adequately define what it is they mean by a dog. If we ask a scientist for help in the matter, we might get some precise statements about structure, or even DNA, which has very little to do with what we are seeking.

The result is an impoverishment of language and thought. The most important things, including "importance" itself, are outside the range of scientific precision and discourse. The most important things can only be spoken of in everyday language, a point recognized by St. Thomas and McLuhan.

A typical quote from Thomas on this matter:

Multitudinis usus, quem in rebus nominandis sequendum philosophus censet, communiter obtinuit ut sapientes dicantur qui res directe ordinant et eas bene gubernant. Unde inter alia quae homines de sapiente concipiunt, a Philosopho ponitur quod sapientis est ordinare.
The way most people use words, which the philosopher says should be followed when naming things, commonly terms wise those directly order things and govern them well. Thus among all the other things that men think of the wise man, the Philosopher sets forth that it is the role of the wise man to order things.

Despite that hair-splitting associated with Scholastic philosophy, Thomas followed Aristotle in building his definitions step by step from common language. It was otherwise in modern philosophy. McLuhan notes the role of Descartes in the language of modernity:

The print in its clumsy woodcut-phase reveals a major aspect of language; namely, that words cannot bear sharp definition in daily use. When Descartes surveyed the philosophical scene at the beginning of the seventeenth century, he was appalled at the confusion of tongues and began to strive toward a reduction of philosophy to precise mathematical form. This striving for an irrelevant precision served only to exclude from philosophy most of the questions of philosophy; and that great kingdom of philosophy was soon parceled out into the wide range of uncommunicating sciences and specialties we know today.
Understanding Media Marshall McLuhan, ch. 16 "The Print"

McLuhan here refers to "irrelevant precision", and this expression takes us back to Aristotle's Ethics. Aristotle tells us: "It is the mark of an educated mind to expect that amount of exactness (akribeia) in each kind which the nature of the particular subject admits. It is equally unreasonable to accept merely probable conclusions from a mathematician and to demand strict demonstration from an orator." (Nicomachean Ethics, I, iii, 1094b20 ff). Thomas Aquinas uses the term "certainty" (certitudo) instead of "precision" to render the Greek akribeia.

Deinde cum dicit: eodem utique modo etc., ostendit quod auditorem oportet acceptare in moralibus praedictum modum determinandi. Et dicit, quod debitum est, quod unusquisque recipiat unumquodque (eorum) quae sibi ab alio dicuntur eodem modo, id est secundum quod convenit materiae. quia ad hominem disciplinatum, idest bene instructum, pertinet, ut tantum certitudinem quaerat in unaquaque materia, quantum natura rei patitur. non enim potest esse tanta certitudo in materia variabili et contingenti, sicut in materia necessaria, semper eodem modo se habente. et ideo auditor bene disciplinatus nec debet maiorem certitudinem requirere, nec minori esse contentus, quam sit conveniens rei de qua agitur. propinquum enim peccatum esse videtur, si aliquis auditor acceptet aliquem mathematicum persuasionibus rhetoricis utentem, et si expetat a rhetorico demonstrationes certas, quales debet proferre mathematicus. utrumque enim contingit ex hoc, quod non consideratur modus materiae conveniens. nam mathematica est circa materiam, in qua invenitur omnimoda certitudo. rhetorica autem negotiatur circa materiam civilem, in qua multiplex variatio accidit.

McLuhans "Thomistic" theory of formal causality is related to his own theory of participation in various media, the distinction between hot and cold media. The various media change the way we see the world, and the media, in a certain way, stand in place of our sensus communis. These views were developed by Walter Ong (who wrote his PhD under McLuhan's direction)in such works as Ramus' Method and the Decay of Dialogue (Harvard U. Press). With print came an emphasis upon efficient causality. Electric media (the telegraph and subsequent technologies) re-introduce a sensitivity to formal causality. McLuhan writes to Peter Drucker (Letters, p. 259, Dec. 15, 1959):

" ... I refer to formal cause not in the sense of the classification of forms" (the taxonomies of Linnaeus? - HM) "but their their operation upon one another."
Kantian philosophy had a place for formal causality, which had been shelved in the centuries leading up to Kant, but its place was not in the world, in things, but in the human mind. The world of his time recognized only efficient causality. McLuhan writes to Drucker:
" media studies have gravitated toward the centre of formal causality, forcing me to re-invent it."
McLuhan obviously had been trying to establish a dialogue with the Thomists in this matter. He writes:
"Two years ago I began to query the local Schoolmen about formal causality, only to discover they had no use for it whatever. As one of them said the other day, 'the danger of formal causality is relativism. We prefer platonism with its static universals as less dangerous."

A decade later, McLuhan reiterates his interest in formal causality (Letters, to J. G. Keogh, p. 412, July 6, 1972):

" approach to media is metaphysical rather than sociological or metaphysical approach is not moral" (McLuhan analyzed and described, but did not moralize. This showed respect for his readers, who are capable of drawing their own moral conclusions, but many thought that McLuhan's descriptions of the effects of media were endorsements as well) "...I am not in any way interested in classifying cultueral forms. I am a metaphysician, interested in the life of the forms and their surprising modalities. I have no interest at all in the academic world and its attempts at tidying up experience."


The doctrine of analogy is at the center of the thought of Thomas Aquinas. Marshall McLuhan weaves analogy into his own thought.

McLuhan wrote to Walter Ong:

My theory is only acceptable to Thomists for whom consciousness as analogical proportion among the senses from moment to moment is quite easy to grasp. But print technology actually smashes that analogical awareness in society and the individual.
(Letters, to Walter Ong, Nov. 18, 1961, p. 280)
He repeats the idea that the written or printed word is opposed to analogical awareness in a letter to Maritain:
Analogy of proper proportionality, for example, is a mode of awareness destroyed by literacy, since the literate man insists on visual connections, where being insists on resonance.
(Letters, to Jacques Maritain, May 6, 1969, p. 371).

McLuhan used the term "resonance" as a synonym for "analogy". This provides a clue to understanding many passages where he mentions "resonance". He wrote to John W. Mole:

...I am a Thomist for whom the sensory order resonates with the divine Logos. I don't think concepts have any relevance in religion. Analogy is not concept. It is community. It is resonance. It is inclusive. It is the cognitive process itself. That is the analogy of the divine logos.
(Letters, to John W. Mole, O.M.I., Apr. 18, 1969, p. 368-9.)
The doctrine of analogy sheds light on McLuhan's dictum that "the medium is the message". He wrote to William Kuhn:
I have always assumed that the user of any medium is the content. The person who turns on an electric light is the content of the electric light, just as the reader of a book is the content of a book. This is standard Aristotelian and Thomistic doctrine, that the cognitive agent is himself thing and content. In the same way, on page 199 (of Kuhn's Post-Industrial Prophets), you miss what to me is the very obvious fact that human consciousness is an analogical mirror far more potent than all other mirrors that merely provide a univocal or matching image.
(Letters, to William Kuhn, Dec. 6, 1971, p. 448)
The Aristotelian doctrine referred to here is the idea that the soul, in knowing, in a certain way becomes that which is known (kai estin o men toioutoV nouV twi panta ginesJai, o de twi panta poiein. De Anima III, v, 430a 10). The mind by itself is without form, empty, and if it did have a form proper to itself, it could not receive other things as known. The mind is also described by Aristotle as the form of forms (kai o nouV eidoV eidwn De Anima III,viii 432a1).

Figure and Ground

McLuhan's views on formal causality come to the fore in his remarks on figure and ground. "Figure" and "ground" are terms taken from Gestalt psychology, and McLuhan frequently applies them in his study of media. In experience, we may assimlate those parts of experience that seem meaningful for us, as reject what we find irrelevant. How this actually works depends on our acquired cognitive habits. McLuhan mentions in this regard a dictum of Thomas: quidquid recipitur, recipitur secundum modum recipientis - the user himself is (in part), the content, via the modus recipientis (cf. Letters, p. 449, to Harry J. Boyle, Dec 8, 1971). What we assimilate in experience can be called "figure", and what we ignore or reject may be called "ground". Platonism (the result of the effect of literacy upon the philosophical mind) separates figure from ground, and the figure becomes "specialized and merely visual archetypes". (Letters, p. 459, to Jane Bret, June 3, 1973).

The man who lives in an oral culture regards words differently - a word is an unrepeatable event. He is more likely to be a Heraclitean ("you cannot step into the same river twice") than a Platonist. Whatever is the same and one behind the words that are spoken on different occasions is by itself ineffable (Heraclitus' respect for the mystery of the logos).

The literate man treats the word as a static entity. The word written down persists, and the actual reading of the word, the "performance" of the script, is subsidiary to the script. Plato was aware of the effects of writing upon the life of the mind, but this does not mean that he was completely immune to these effects.

McLuhan writes:

"...the Platonist, with his specialized and merely visual archetypes (figures without ground rather than merged with ground), gets a sense of divinity from his abstraction of figure from ground. The Aristotelian, with his hylemorphic figure and ground interplay, seems more earthy and rooted."(Letters, p. 459, to Jane Bret, June 3, 1973)
Plato concentrated on forms as causes, while Aristotle explained things by the full interplay of the four causes (see the first book of Aristotle's Metaphysics. The Aristotelian four-fold approach to causality is the antithesis of reductionism. It means that in answering why something is so, there are at last four valid and different explanations, or different approaches in explanation.

Participation: Hot and Cold Media

Participation, a term used by Aquinas, expresses how one thing has a partial share (participare = partem capere - to hold or take a part of a whole) of another. What one thing has in a full and eminent manner, another thing recieves from the first in a partial manner. One thing may have a partial share in the form of another. Knowledge may be described as participation. The knower becomes in a certain way the known, that is, his mind is the "form of forms", something capable of assimilating the form of anything else, and this is why the mind is by itself formless. If the mind was already formed (as in innate knowledge) it could not be receptive to the forms of other things. It could not take on the forms, or participate in the forms of other things. In knowledge the form of the thing known, which exists in its fullness in the thing, is participated by the knower. The knower takes on the form of thing in a partial manner. McLuhan quotes from Aquinas' Commentary on Boethius De Hebdomadibus:

"Suppose that we say that air participates the light of the sun, because it does not recieve it in that clarity in which it is in the sun."(Letters, p. 459, to Jane Bret, June 3, 1973)
McLuhan comments:
"Aquinas seems to say that participation is a 'cooling' process, as well as being a figure-ground relationship, i.e. existence is real cool, but the Platonists are always trying to hot it up by separating figure from ground. Is not the academic seen in general to break figure from ground for the sake of simplicity and intensity?(Letters, p. 459, to Jane Bret, June 3, 1973)"
In the same letter, McLuhan calls Thomas' doctrine of "participation" his "theory of communication".

The Sensus Communis

Aristotle describes the sense power as a logos, which is generally translated as "proportion". oud h aisJhsiV megeJoV estin, alla logoV tiV kai dunamiV ekeinou.(De Anima II, xii 424a 25) We may note briefly that Thomas Aquinas uses the term "ratio" to translate "logos". Of course, "logos" is itself an extremely analogical term, and the latin "ratio" shares much of the family of meaning. In what follows, Aristotle compares the logos of the senses to the adjustment and pitch of a lyre. If the strings of a lyre are struck too hard, its tuning is destroyed. Likewise, if a sense organ is over-excited, its proportion or tuning is destroyed, and this tuning or proportion is one and the same as the sense itself.

Marshall McLuhan develops this line, and we may say that it is central to his thought. Various media excite certain senses, both to the detriment of the whole of the other senses, and sense cognition as a whole. This thought is found throughout McLuhan's works. For example:

Song itself is a slowing down of speech so that the songs of each culture are uniquely patterned by their speech. This is equally true of dance, since every culture that is or ever was in the world possesses a unique ratio of sensory life that can be detected at once in its speech, its dances, or its songs. Any technological innovation in any culture whatever at once changes all these sensory ratios, making all the older songs and dances seem very odd and dated to the young. In all cases sensory change is levered by new technical innovations, since new technology inevitably creates new environments that act incessantly on the sensorium.
(War and Peace in the Global Village, p. 136.)
The effects of new technologies upon the senses may pose a threat to man. McLuhan writes:
The principle of numbness comes into play with electric technology, as with any other. We have to numb our central nervous system when it is extended and exposed, or we will die. Thus the age of anxiety and of electric media ias also the age of the unconscious and of apathy.
(Understanding Media, ch. 4 "The Gadget Lover")
If numbness is a mechanism for coping with sensory overload or imbalance, we might observe with Aristotle that the ultimate and terminal point is the death of organism. Every animal possesses the sense of touch, indeed the sense of touch defines the animal. The sense of touch is a kind of mean (mesothV) between all tangible qualities, and the basis of all the other senses. If deprived of the sense of touch, animals must die. To cease to feel is to cease to be an animal. (cf De Anima III, xiii, 435a-b)

The sensus communis or aisQhsiJ koinh is the sense of senses. It is not quite the same as intellect, but it is still a step above simple sensation. Aristotle presents his doctrine of the common sense in the first chapter of Book III of De Anima. Each sense has its own proper object or objects, as touch perceives hardness, softness, heat, cold and so forth, and hearing perceives tone. Vision perceives color. However, these sense data by themselves do not constitute the perception of things as such. There are attributes called the common sensibles which involve all the senses working together. These are motion, rest, shape, size, number and unity. There is thus a sense that oversees and unifies the other senses, whether this be conceived as a separate faculty or a harmonic synergy of all the proper senses.

McLuhan's insight was that this common sense is trained. It can and does acquire habits. It requires very specific habits when sense experience is mediated by various technologies (even a technology as simple as writing). In fact, the function of the common sense in unifying sense data in due proportion in order to present the solid and moving world is extended, and partially supplanted by electronic media. The result of these technologies is that the new man is already "an organism that now wears its brain outside its skull and its nerves outside its hide."(Understanding Media, ch. 6 "Media as Translators"). Previous technologies also extended our senses, but the electronic media are all inclusive. For the new man to be deprived on his Internet, telephone, television and so forth is as traumatic as losing one of his organic senses. Not only does the technology serve the man, but the man also serves the technology.

If the electronic technology places the center of our common sense outside ourselves, it also creates a common sense which is shared by a community. McLuhan writes that "an external consensus or conscience is now as necessary as private consciousness".(Understanding Media, ch. 6 "Media as Translators") While the media creates its own external consensus, and so programs man, man also programs the media. I may comment that this can create a feedback loop. For example, the television news creates a world for us. For myself and my neighbours, the Persian Gulf War or the Kosovo conflict are synonymous with the television experience. The Persian Gulf War is as much a landmark marked in television as Melrose Place. It is easy to see how the News feeds upon itself. The fact of the electronic mediation of the event in turn becomes electronically mediated. When he who programs his media environment is himself the product of that environment, he creates an environment that is no longer merely a transparent medium of communication, but a reality in itself.

McLuhan refers specifically to the classical doctrine of the common sense:

Our very word "grasp" or "apprehension" points to the process of getting at one thing through another, of handling and sensing many facets at a time through more than one sense at a time. It begins to be evident that "touch" is not skin but the interplay of the senses, and "keeping in touch" or "getting in touch" is a matter of a fruitful meeting of the senses, of sight translated into sound and sound into movement, and taste and smell. The "common sense" was for many centuries held to be the peculiar human power of translating one kind of experience of one sense into all the senses, and presenting the result continuously as a unified image to the mind. In fact, the image of a unified ratio among the senses was long held to be the mark of our rationality, and may in the computer age easily become so again.
(Understanding Media, ch. 6 "Media as Translators")

Medium and Media

In The Gutenberg Galaxy, (the very end of the first chapter, also entitled "The Gutenberg Galaxy"), Marshall McLuhan refers the reader to an article by Thomas Aquinas, Utrum Christus debuerit doctrinam suam Scripto tradere - Whether Christ ought to have committed his teaching to writing (Summa Theologica III q. 42, art. 4). McLuhan's comments recapitulate what Thomas says:

The pre-Socratics were still mainly in a non-literate culture. Socrates stood on the border between that oral world and the visual and literate culture. But he wrote nothing. The Middle Ages regarded Plato as the mere scribe or amanuensis of Socrates. And Aquinas considered that neither Socrates nor Our Lord committed their teaching to writing because the kind of interplay of minds that is in teaching is not possible by means of writing.

Thomas states that it was fitting that Christ did not commit his teaching to writing. There were three reasons.

First, because of his own dignity. The more excellent the teacher, the more excellent should be his way of teaching. So for Christ, as the most excellent teacher, it was fitting that he used a method that would impress his teaching upon the hearts of his listeners. And so, the Gospel of Matthew says that "he taught as one who had power" (Matt. 7, 29). Among the Gentiles, Pythagoras and Socrates were the most excellent teachers, and neither did they decide to write anything. Aquinas writes - Writings are order to impress teaching upon the hearts of listeners as their end - Scripta enim ordinantur ad impressionem doctrinae in cordibus auditorum sicut ad finem. So it seems, that for written words to have their effect, they must be read aloud, and in that way they make an impression upon the hearts of those present. Here, what Thomas does not say, is that the written word would stand in the middle, as a medium, which would dilute the direct effect of the teacher speaking his own living words.

Second, because of the excellence of Christ's teaching, which cannot be captured by written words. And so John the Apostle wrote that there were many other things that Christ did, which if they were written down, he thought the world itself could not hold the books that would have to be written (John 21:25). Augustine adds that it is not a matter of a great quantity of books, but that it was the capacity of the readers to grasp the truth. It might, then, be a small book, but no human reader, or even all the readers in the world, could grasp its content.

Third, so that Christ's teaching would come from Him to all men in a certain order. He taught His disciples directly, and these afterward taught others by the spoken and the written word. If he had written things down, his doctrine would have come directly to all men. What is the problem with this? Thomas may provide the answer in his commentary on Boethius' De Trinitate.

Below is the full text of Question II, article 4, which asks Utrum Divina sint velanda novis et obscuris verbis - whether divine matters should be veiled by new and obscure words:
First, Thomas presents the objections, which he will answer later
Ad quartum sic proceditur. Videtur quod divina in scientia fidei non sunt obscuritate verborum velanda,quia, ut dicitur Prov. 14, doctrina prudentium facilis. Ergo sine obscuritate verborum proponi debet. We move on to the fourth article. It seems that divine matters in the science of faith should not be veiled by the obscurity of words, because, as Prov. 14 says, the doctrine of the prudent is easy. Therefore it should be set forth without obscurity of words.
Praeterea, eccli. 4: ne abscondas sapientiam in decore eius; et prov. 11: qui abscondit frumenta, glossa: praedicationis, maledicetur in populis. ergo verba sacrae doctrinae non sunt velanda. Furthermore, Eccl. 4: do not hide wisdom in its beauty: and Prov. 11: he who hides away fruit (the gloss says: the fruit of preaching/teaching) will be cursed among the peoples. Therefore the words of sacred doctrine should not be veiled.
Praeterea, Matth. 10: quod dico vobis in tenebris, glossa: in mysterio, dicite in lumine, glossa: aperte. Ergo obscura fidei sunt magis reseranda quam occultanda difficultate verborum.Furthermore, as it says in Matthew 10: what I say to you in darkness (the gloss adds: in mystery), speak in the light (the gloss adds: openly). Therefore the obscure matters of faith ought rather to be broadcast than hidden.
Praeterea, doctores fidei sunt sapientibus et insipientibus debitores, ut patet Rom. 1. Ergo taliter debent loqui, ut a magnis et a parvis intelligantur, id est sine obscuritate verborum. Furthermore, the teachers of faith are debtors to the wise and the unwise, as we see in Romans 1. Therefore they ought to speak in such a way that they may be understood by the great and the small, that is, without obscurity in their words.
Praeterea, Sap. 7 dicitur: quam sine fictione didici et sine invidia communico. Sed ille qui eam occultat, non eam communicat. Ergo videtur invidiae reus. Furthermore, in Wisdom 7 it says: what I leaned without fiction I also share without envy. But he would would obscure it, does not share it. Therefore he seems to be guilty of envy.
Praeterea, Augustinus dicit IV De Doctrina Christiana: Expositores Sacrae Scripturae non ita loqui debent, tamquam se ipsos exponendos proponant, sed in omnibus sermonibus suis primitus ac maxime ut intelligantur elaborent ea perspicuitate dicendi, ut multum tardus sit qui non intelligit. Furthermore, Augustine says in IV De Doctrina Christiana: Those who explain Holy Scripture should not speak as if they were putting their own selves forth to be explained, but in all their words it is most important that they labour to be understood with a clearness of speaking so that only someone very slow would not understand.
Below, Thomas begins to explain his own view on the matter
Sed contra est quod dicitur Matth. 7: Nolite sanctum dare canibus neque mittatis margaritas vestras ante porcos, ubi dicit glossa: res absconsa avidius quaeritur, celata venerabilius conspicitur, diu quaesita carius tenetur. Cum ergo sacra documenta expediat summa veneratione intueri, videtur quod non debeant publicari, sed obscure tradi. But on the contrary, there is what it says in Matthew 7: Do not give what is holy to dogs, nor cast your pearls before swine, where the gloss says: a hidden thing is more avidly sought, a concealed thing is seen with greater reverence, and that which was long sought is held to be more precious. Since it is right that the Holy teachings should be regarded with the greatest reverence, it seems that they should not be published, but passed on in an obscure manner.
Praeterea, Dionysius dicit 1 c. Ecclesiasticae Hierarchiae : omnem sanctam laudem non tradas alteri praeter aeque ordinatos tibi deiformes, id est divinas laudes, quibus omnia sacra documenta complectitur, non tradas nisi tibi similibus. Sed si verbis conspicuis scriberentur, omnibus paterent. Ergo secreta fidei sunt verborum obscuritate velanda. Furthermore, Dionysis says in 1 Ecclesiastic Hierarchy: Do not pass on any Divine Praise to any man apart from those who are conformed to God and ordered to you. That is, do not pass on the Divine Praises, in which all the Holy Teachings are contained, to any except those like you. But if these were written in plain words, they would be open to all. Therefore the secret matters of faith should be veiled by the obscurity of words.
Praeterea, ad hoc est quod dicitur Luc. 8: vobis, id est perfectis, datum est nosse mysterium regni dei, id est intelligentiam scripturarum, ut patet per glossam, ceteris autem in parabolis. Ergo oportet aliqua verborum obscuritate a multitudine occultari. Furthermore, we may apply to his what it says in Luke 8: to you, (that is, to the perfect), it has been given to know the mystery of the Kingdom of God (that is, the understanding of scriptures, as is clear from the Gloss), but it is given to the rest in parables. Therefore some things should be hidden from the multitude by obscurity of words.
Responsio. Dicendum quod verba docentis ita debent esse moderata ut proficiant, non noceant audienti. Quaedam autem sunt quae audita nemini nocent, sicut ea quae omnes scire tenentur; et talia non sunt occultanda, sed manifeste omnibus proponenda. Quaedam vero sunt quae proposita manifeste auditoribus nocent; quod quidem contingit dupliciter. Uno modo, si arcana fidei infidelibus fidem abhorrentibus denudentur. Eis enim venirent in derisum; et propter hoc Dominus dicit Matth. 7: Nolite sanctum dare canibus; et Dionysius dicit c. 2 Caelestis Hierarchiae: quae sancta sunt circumtegens ex immunda multitudine tamquam uniformia custodi. Secundo, quando aliqua subtilia rudibus proponuntur, ex quibus perfecte non comprehensis materiam sumunt errandi; unde Apostolus dicit 1 Cor. 3: ego, fratres, non potui vobis loqui quasi spiritualibus, sed tamquam parvulis in christo lac potum vobis dedi, non escam. Unde Exodi 22 super illud: si quis aperuerit cisternam etc., dicit glossa Gregorii: qui in sacro eloquio iam alta intelligit, sublimes sensus coram non capientibus per silentium tegat, ne per scandalum interius aut fidelem parvulum aut infidelem, qui credere potuisset, interimat. Haec ergo ab his, quibus nocent, occultanda sunt. The response. It is to be said that the words of one who teaches should be moderated to benefit the listener rather than harm him. Some things harm no one when heard, such as those things that all are bound to know; and such things should not be hidden, but should be set forth plainly to all. There are other things, however, which if set forth clearly may harm the listeners, and this happens in two ways. In one way, if the hidden things of the faith are laid bare for the infidels who abhor the faith. These things would come into derision for them, and on the accound the Lord says (Matthew 7): Do not give what is holy to the dogs, and Dionysius says (c. 2, Caelestis Hierarchiae): Guard the things that are holdy, hedging them around from the unclean crowd as one form. Second, when certain subtle matters are set forth to the uneducated, and not understanding these things perfectly they have matter for error; hence the Apostle says (I Cor 3): I, brothers, could not speak to you as to spiritual men, but as to children in Christ I have given you milk to drink, rather than solid food. Hence, commenting on Exodus 22, the passage: if anyone opens a cistern etc., the gloss of Gregory says: he who already understands lofty things in Sacred Speech, should hide by silence the sublime meanings when in the presence of those who do not grasp these things, lest by scandal he slays within the small faithful or the infidel who otherwise would be capable of belief. These things therefore should be hidden from those who would suffer harm from them.
Sed in collocutione potest fieri distinctio, ut eadem seorsum sapientibus manifestentur et in publico taceantur. Unde dicit Augustinus in IV l. De Doctrina Christiana: sunt quaedam quae vi sua non intelliguntur aut vix intelliguntur, quantolibet et quantumlibet quamvis plenissime dicentis versentur eloquio, quae in populi audientiam vel raro, si aliquid urget, vel numquam omnino mittenda sunt. Sed in scribendo non potest talis distinctio adhiberi, quia liber conscriptus ad manus quorumlibet venire potest, et ideo sunt occultanda verborum obscuritatibus, ut per hoc prosint sapientibus qui ea intelligunt et occultentur a simplicibus qui ea capere non possunt. Et in hoc nullus gravatur, quia qui intelligunt, lectione detinentur, qui vero non intelligunt, non coguntur ad legendum. Unde Augustinus dicit in eodem libro: in libris qui ita scribuntur, ut ipsi sibi quodammodo lectorem teneant, cum intelliguntur, cum autem non intelliguntur, molesti non sunt volentibus legere, non est hoc officium disserendi, ut vera, quamvis ad intelligendum difficillima, ad aliorum intelligentiam perducamus. But in speaking with someone, we may make a distinction, so that the same things may be made clear to the wise in private, but passed over in silence in public. Hence Augustine says in book IV, De Doctrina Christiana: some things are not understood by their own power or understood right away, no matter how fully they are treated in the speech of the one who speaks, things which never, or only rarely in case of need, are set forth for the people to hear. But in writing, we cannot apply such a distinction, because a book once written can come into the hands of anyone, and so these things are to be hidden by obscure words, so they may benefit the wise who will understand them, while they are hidden from the simple who cannot grasp them. No one is burdened in this, because the reader who understands will be held in reading, while those who do not understand are not forced to read. So Augustine says in the same book: Some books are written so they hold the attention of the reader when they are understood, but when they are not understood, they do not cause any trouble for the reader. In such books, do we not have the task of explaining things, so that truths, even those most difficult to understand, may be brought to the understanding of other people?
Ad primum ergo dicendum quod auctoritas illa non est ad propositum. Non enim est sensus auctoritatis quod doctrina prudentium sit facilis active, id est quod faciliter doceant, sed passive, quia faciliter docentur, ut patet per glossam. To the first objection, it is to be said that this authoritative remark is irrelevant to the question. This authoritative quote does not mean that the doctrine of prudent men is easy in an active sense, that is, that they teach it with ease, but in a passive sense, because it is easily learned, as is clear in the Gloss.
Ad secundum dicendum quod auctoritates illae loquuntur de illo qui abscondit ea quae manifestanda sunt, unde Eccli. 4 praemittitur: non retineas verbum in tempore salutis. Per hoc autem non removetur, quin ea, quae sunt occultanda, debeant obscuritate verborum celari. To the second objection, it is to be said that these authoritative quotes speak of the man who hides things that should be made manifest, and so in Eccl. 4, this remark is preceded by another: do not hold back your word in the time of need. But by this it is not denied that the things that should be hidden ought to be concealed by obscurity of words.
Ad tertium dicendum quod doctrina christi est publice et plane praedicanda, ita quod unicuique sit planum illud quod expedit ei scire, non autem ut publicentur ea quae scire non expedit. To third third objection, it should be said that the doctrine of Christ should be preached publically and plainly, so that that which each should know is plain to that person, but the things that do not benefit him to know are not made public.
Ad quartum dicendum quod doctores sacrae scripturae non sunt ita sapientibus et insipientibus debitores, ut eadem utrisque proponant, sed ita quod utrisque proponant ea quae eis competunt. To the fourth objection, it is to be said that those who teach Holy Scripture are not debtors to the wise and unwise in such a way that they set forth the same things to both, but in such a way that they set forth to each those things that are suited to them.
ad quintum dicendum quod non est ex invidia quod subtilia multitudini occultantur, sed magis ex debita discretione, ut dictum est. To the fifth objection, it is to be said that it is not out of jealousy that subtle matters are hidden from the crowd, but more out of due discretion, as was said.
Ad sextum dicendum quod Augustinus loquitur de expositoribus qui ad populum loquuntur, non de his qui scripto aliquid tradunt, ut ex consequentibus patet. To the sixth objection, it is to be said that Augustine is speaking of those who interpret things speaking to the public, not of those who pass on something in writing, as is clear from the remarks that follow.

So there is a place for obscurity. There is an order in learning which requires that the writer use different modes for the public and for the expert. Whether or not Marshall McLuhan was deliberately obscure, and if so, whether he had such "Thomistic" reasons, I leave to others to decide. However, frequent passages in his letters (some cited on this web page) show that he did not trust the academic's love of classification and simplification, as this could distort the truth out of a desire for clarity. Although McLuhan, to my knowledge, does not cite this particular passage, he does on occasion cite this work of Aquinas. This is not much, of course, to draw a clear link, but my intention is only to suggest what is possible.

Bibliographical Information

This is not a complete bibliography, but is intended to provide more complete references to citations in this article. My citations, apart from those referring to the Letters, are to the chapters, since the paginations may differ in different editions, and I do not think that you all have access to the same exact editions of oft reprinted books.