What are tetrads?

Marshall and Eric McLuhan’s Laws of Media (1988) treats every human artefact as something you can see — a car, a telephone, a poem — by asking four questions at once. The work is how a culture becomes aware of the technologies it already lives inside. The purpose here is the same: that no one lives inside a technology they cannot see.

The four laws, asked of any artefact:

• What does it enhance?
• What does it reverse into?
• What does it retrieve?
• What does it make obsolete?

A tetrad is never finished. Nothing is overwritten; every reading is another layer. Perception is not a competition. Citation stays with the sheet: Marshall and Eric McLuhan.