> despite all the theoretical work, it's not physically possible to bias a coin to any notable degree. > I get the idea as shorthand for a binary outcome, but

> despite all the theoretical work, it's not physically possible to bias a coin to any notable degree. > I get the idea as shorthand for a binary outcome, but the way you make a coin fair is to flip it. That's a case of working from false assumptions that aren't necessarily true in practice. The way to make a coin flip fair is to control as many variables as possible during the flip and landing - because that is what is done by people who bias the flip. Only one of these variables is the coin itself. Bias sometimes exists in the apparatus around the coin. After all some historical coins have ferrous metal in them, as the simplest example. Bias can also be introduced by the people performing the flips. For example, there are people who can flip a coin onto its edge or with an outcome biased towards heads or tails. A flip onto the coin's edge can even be done by an amateur. [1] After all, even without bias a coin can land on its edge. See this CBS News video from a Soccer game's ref flipping a coin. [2] [1] https://www.youtube.com/watch?v=M0I-xm7iCBU https://www.youtube.com/watch?v=M0I-xm7iCBU. [2] https://www.youtube.com/watch?v=Sz3VwRLsfX0 https://www.youtube.com/watch?v=Sz3VwRLsfX0