Shoe Event Horizon

The Shoe Event Horizon is a mock theory invented by Douglas Adams for "The Hitchhiker's Guide to the Galaxy" radio series.

The foundation of the theory is that when depressed, people tend to look down, and when they look down, they see their shoes. To cheer themselves up, they might buy themselves a new pair. Thus, in a generally depressed society, demand for shoes will rise.

In the critical condition, demand for shoes rises faster than the capacity to make good quality footwear. As shoe quality decreases, the demand increases further because shoes wear out faster and need to be replaced more often; as the demand for shoes increases, cheap mass production causes shoe quality to drop even more. What results is a spiral of increasing shoe demand and decreasing shoe quality. Eventually, this destabilises the economy to the point where it is "no longer economically viable to build anything other than shoe shops", and planetary society collapses.

The Guide also mentions a planet that passed the shoe event horizon (called Frogstar B in the book and Brontitall in the radio show) where the survivors eventually evolved into birds so as to avoid touching the ground, never needing shoes again.

Inspiration

Adams had gone to London's Oxford Street where, quoting him, "You can't throw a brick without breaking a shoe shop window". Despite every shop stocking thousands of shoes, none had a pair which was the right size, price, or colour, or which was comfortable, durable or stylish without being outrageous.

Working off his frustration, Adams invented the planet Brontitall, whose civilization had collapsed into the Shoe Event Horizon. Not content with one poke at the industry, Adams also invented the predatory Dolmansaxlil Shoe Corporation, whose name is created by taking syllables from the names of well-known London shoe stores: "Dolcis"; "Freeman, Hardy and Willis"; "Saxone"; and "Lilley and Skinner". All these stores were owned at the time by the British Shoe Corporation which dominated the UK footwear market and was the largest footwear retail company in the world.