Straight razor King C. Gillette: a double-edged safety razor with replaceable blades. These new safety razors did not require any serious tutelage to use. The blades were extremely hard to sharpen, and were meant to be thrown away after one use, and rusted quickly if not discarded. They also required a smaller initial investment, although they cost more over time. Despite its long-term advantages, the straight razor lost significant market share. As shaving became less intimidating and men began to shave themselves more, the demand for barbers providing straight razor shaves decreased. Since 2012, production of straight razors has increased multifold. Straight
Occam's razor reject the simple hypotheses. Recent advances employ information theory, a close cousin of likelihood, which uses Occam's razor in the same way. Francis Crick has commented on potential limitations of Occam's razor in biology. He advances the argument that because biological systems are the products of (an ongoing) natural selection, the mechanisms are not necessarily optimal in an obvious sense. He cautions: "While Ockham's razor is a useful tool in the physical sciences, it can be a very dangerous implement in biology. It is thus very rash to use simplicity and elegance as a guide in biological research." In biogeography,