McLuhan, recognizing the shortened attention-span of a television-influenced audience, used epigrams, which he called "probes". McLuhan's probes are short snippets of wit, sometimes self-supportive and sometimes self-contradictory, calculated to elicit a reaction.

A good example of a McLuhan probe is "The medium is the message". McLuhan often utilized hyperbole as a rhetorical device to provoke discussion. When McLuhan says "...at the speed of light man has neither goals, objectives nor private identity. He is an item on the data bank-software only, easily forgotten", he is testing an audience, looking for an argument. At other times, he is eminently quotable: "We are living far ahead of our thinking" is today a commonplace that was startling when McLuhan said it at the end of the '60's