Behind McLuhan's concept of the dynamic 'senses', but rarely explicit, is a concept of 'energy'.

Although McLuhan's use of the term may be attributed to Pierre Teilhard de Chardin, it is an ancient concept with which he would have been familiar from his doctoral study.

Heraclitus named 'fire' the source of energy in the universe; Thales, 'water'; Anaximander, the Indeterminate; Anaximenes, 'air'; Aristotle, says Étienne Gilson in God and Philosophy, one of the books McLuhan references in his doctoral thesis, is the first to identify the first principle as that of 'God'.1

Aquinas follows Aristotle, arguing that 'whatever is in motion is put in motion by another .... It is ... impossible that in the same respect and in the same way a thing should be both mover and moved, i.e. that it should move itself.... it is necessary to arrive at a first mover, put in motion by no other; and this everyone understands to be God'.2

Teilhard employs a dialectic between 'radial energy' and 'tangential energy' to argue that evolution must inevitably occur at the level of a plurality, not at the level of the individual organism.3

Thus, just as new inventions (e.g. the telegraph) are invented at the same time in different parts of the world, so too do species evolve across the Earth as a plurality, due to the 'radial' energy that they share.4

McLuhan, while he does not stress the concept of 'energy', echoes Teilhard in a number of places, writing in Understanding Media of 'hybrid energy',5 and later describing the 'environment' as 'a special organization of available energies'.6