McLuhan read Havelock’s Crucifixion of Intellectual Man soon after it was published in 1951.¹

In it Havelock pointed to 3 forms which contest as an “ancient quarrel” in the human soul, in society and in all history. McLuhan described a similar contest of 3 ‘trivial’ forms in his 1943 Nashe thesis and continued to do so all his life as, eg, the ear versus the eye and their integration in the sensus communis. Or, in a variation which confusingly cut across the former, as the antithetical dualism of the eye and the integration of such dualism in the ear.

The notion of the 3 forms of Being is at least as old as Plato² (and was arguably many millennia old even then³).  Neither Havelock not McLuhan originated the idea, no did either of them first find it in the other.

Here is Havelock in Crucifixion:

If Prometheus be the [1] intelligence of man, the enemy he confronts bears a close resemblance to that other spiritual force, man’s [2] will to power. It [intelligence] is an influence equally operative along with [2] technology and [3] philanthropy in the history of human societies. (58)

for the dramatist, this creed of [2] power and force [in Zeus] is [also] an element in man himself, which shares with his [1] intelligence the responsibility for making his history. It is consistent with this view of Zeus [as exemplifying power, but not only power] that Prometheus should be able to foresee a [3] reconciliation with his tormentor [Zeus]. In this he imaginatively recognizes the principle that is, historically speaking, his other half, and can look forward to the day when the two sides of man’s nature [1: intelligence and 2: power] will be [3] harmonized. (58-59)

while the [2] practical present which decides what we do, what we vote, what we say, is treated as one closed system, the past, [1] explored, analyzed, interpreted, is treated as another closed system, which can be abstractly related to ourselves without ever [3] interpenetrating us. (…) Does this suggest that [1] historical science is self-defeating? That the more we know, the more foolishly we act? The equation is not quite so frustrating as that, but its terms can be calculated only when we are prepared to revise our notions of what the [1] intelligence of man really is, what procedures activate his brain in [3] harmony with his [2] living pattern, and what do not. (74) 

Whether it be the Greek [1] intellect or the Semitic [1] soul that is offered up [to crucifixion], the enemy is still the [2] will to power, as it exists in all men. And the solution to the conflict is foreshadowed, by Greek as by Hebrew insight, as an act of [3] reconciliation. (108)

The crucifixion [of Prometheus and of the foresight he personifies] remains true in spirit to the tragic humanism of the Greeks. Though the task of intellect as such is utopian and clean-cut, in actual history no utopia is offered to man, but a prolonged historical agony⁴ which arises out of the  [3]  dialectic between  [1] science and [2] power. This becomes a discipline for man, the logic of which he cannot escape. For neither can his soul be satisfied with relationships of [2]  force, nor can it surely attain, as the nineteenth century thought it could, the relationships of freedom, grounded in a liberal mood of [1] scientific humanism. (…) But the [1]  Promethean in man [namely, intelligence and foresight] cannot die. Once he has learned to face his universe without delusions (…) he may discover [3] new resources of moral strength in and for himself. If he reinforce the [3] courage of his [1] intellect, he may yet achieve a better [3] reconciliation between his  [2] will to power and his [1] scientific vision. (108-109)