For McLuhan, reading Sigfried Giedion’s Space, Time and Architecture in 1943 was a “one of the great events of my lifetime” (as he noted in the Stearn interview).

A central aspect of that importance for McLuhan was Giedion’s appeal to human integrity, to the union of thought and feeling, which could be re-established, he claimed, through focus on the common root of science and art.

Throughout the nineteenth century the natural sciences went splendidly ahead, impelled by the great tradition which the previous two hundred years had established, and sustained by problems which had a direction and momentum of their own. The real spirit of the age came out in these researches in the realm of thinking, that is. But these achievements and results were regarded as emotionally neutral, as having no relation to the realm of feeling. Feeling could not keep up with the swift advances made in science and the techniques. The century’s genuine strength and special accomplishments remained largely irrelevant to man’s inner life.
This orientation of the vital energies of the period is reflected in the make-up of the man of today. Scarcely anyone can escape the unbalanced development which it encourages. The split personality, the unevenly adjusted man, is symptomatic of our period.
But behind these disintegrating forces in our period tendencies leading toward unity can be observed. From the first decade of this century on, we encounter curious parallelisms of method in the separate realms of thought and feeling, science and art. Problems whose roots lie entirely in our time are being treated in similar ways, even when their subject matter is very different and their solutions are arrived at independently.
In 1908 the great mathematician Hermann Minkowski first conceived a world in four dimensions, with space and time coming together to form an indivisible continuum. His Space and Time¹ of that year begins with the celebrated statement, “Henceforth, space by itself, and time by itself, are doomed to fade away into mere shadows, and only a kind of union of the two will preserve an independent reality”² It was just at this time that in France and in Italy cubist and futurist painters developed the artistic equivalent of space-time in their search for means of expressing purely contemporaneous feelings.³