Razor razors were the most common form of shaving before the 20th century and remained common in many countries until the 1950s. Barbers were specially trained to give customers a thorough and quick shave, and a collection of straight razors ready for use was a common sight in most barbershops. Barbers still have them, but they use them less often. Straight razors eventually fell out of fashion. Their first challenger was manufactured by King C. Gillette: a double-edged safety razor with replaceable blades. Gillette's idea was the use of the "loss leader" concept, in which the razors were sold at a
Hanlon's razor a book compilation of various jokes related to Murphy's law published in Arthur Bloch's "Murphy's Law Book Two: More Reasons Why Things Go Wrong!" (1980). Subsequently, in 2002, the "Jargon File" entry noted the same. Hanlon's razor Hanlon's razor is an aphorism expressed in various ways, including: An eponymous law, probably named after a Robert J. Hanlon, it is a philosophical razor which suggests a way of eliminating unlikely explanations for human behavior. Inspired by Occam's razor, the aphorism was popularized in this form and under this name by the "Jargon File", a glossary of computer programmer slang. In 1990,