Graeme Patterson‘s excellent History and Communications (1990) records a late exchange between McLuhan’s old Winnipeg buddy¹ Tom Easterbrook, and Easterbrook’s mentor, colleague and close friend at UT, Harold Innis:

In the spring of 1952, when [Innis] was dying of cancer, the economist W.T. Easterbrook wrote to him about his own “current preoccupation with McLuhan’s ‘juxtaposition of unlikes’ (…) It is a method not at all uncommon in your own writings, but it is only recently that I have begun to see its possibilities. It is the only way I know out of the dilemma of narrative vs ‘scientific’ history.”
“I agree with you”, replied Innis, “about the importance of juxtaposition along the lines suggested by McLuhan. It seems to offer the only prospect of escape from the obsession with one’s own culture, but of course needs to be carefully considered since, while one’s own views of one’s culture change as a result of looking at other cultures, nevertheless the problem of objectivity always seems to emerge.” (28, with notes 8 and 9 to this passage on  p 229)

As described in ‘Innis and McLuhan in 1936’² Innis had long been ambiguous about the prospects of scientific rigor in the social sciences.  He seems to have remained so until his death. But Easterbrook, at least, could see that the simultaneous double perspective or juxtaposition method that McLuhan was advocating (mainly from his reading of Eliot and Pound) did offer such a prospect — but exactly not by extricating itself (per impossibile) from finitude, either in the performance of the subject or in the knowledge of the object. Instead, finitude might be perceived and exercised as itself juxtaposed with truth — however ‘unlikely’ such an “inclusive image” might seem in some perspectives. But how else could we have all the sciences that we do? Or, indeed, how else could we have all the routine familiarity we have in going about our everyday lives?

Later in History and Communications, Patterson tied Innis’ reply to Easterbrook to his reading of the following passage from The Mechanical Bride:

The cultural patterns of several societies, quite unrelated to one another or to our own, are abruptly overlayered [in contemporary anthropology like that of Margaret Mead] in cubist or Picasso style to provide a greatly enriched image of human potentialities. By this method the greatest possible detachment from our own immediate problems is achieved. The voice of reason is audible only to the detached observer. (3)

Patterson commented:

It was this method of achieving “the greatest possible detachment”, it would appear, that Innis had in mind in making his strange reply to Easterbrook. (35)

“Detachment” was  certainly one of “the conditions of freedom of thought” sought by Innis.  But what Innis did not live long enough to understand in McLuhan (let alone to affirm with McLuhan) was the compatibility of “unlikes” even when their “juxtaposition” were taken to the extreme of “the greatest possible detachment”.  This extreme compatibility of “unlikes” was at the heart of McLuhan’s “ceaseless quest for the inclusive image” and of his Catholic persuasion.