Young children often protest, "That's not fair." Even very young children understand what is fair. People who study fairness have tried to say what it means. Philosophers describe justice as the opposite of arbitrariness. A common idea of justice is applying the same rules to everyone, consistently. Rawls asked people to imagine sitting behind a veil of ignorance. The veil keeps them from knowing who they are. That way, arbitrary facts do not influence the agreement. Ethics Unwrapped says that by being ignorant of our circumstances, we can more objectively consider how societies should operate.

Casting or drawing lots has been used for thousands of years to deal with uncertainty and ensure fairness. Lotteries have been accepted as a fair, democratic way of making difficult choices. Before a football game, the captain announces heads or tails before the referee flips the coin. The toss decides who gets first choice of receiving the kickoff or which goal to defend. If a football coin lands at an angle in snow or mud, the referee will re-flip it. Under the Laws of the Game for soccer, the referee tosses the coin. It must be the referee who tosses it.

Magna Carta's Clause 39 says no free man is to be arrested or imprisoned except by the lawful judgment of his peers or by the law of the land. The rule-of-law explainer says those in power, including judges, police and lawmakers, must treat people equally and not make arbitrary distinctions. The Fourteenth Amendment says no state may deny any person the equal protection of the laws or deprive anyone of life, liberty or property without due process of law. A basic idea of fairness: cases that are alike should be treated alike. In the United States, trial by jury is a right guaranteed in the Constitution.

The Preamble to the U.S. Constitution lists establishing Justice among its goals, and the Constitution says crimes shall be tried by jury. The Sixth Amendment trial right concerns an impartial jury, also known as a jury of your peers. In the late 1400s, artists began to portray Lady Justice with a blindfold, but the blindfold was meant to be sarcastic. She is often shown with a sword for the power of the law and with scales for two sides of an argument and eventual balance and justice. In the Illinois Supreme Court Building, Lady Justice appears with her eyes uncovered.

Part of being fair is following the rules. Fair play is usually thought of as following the rules. Fair play includes respecting the referee. It is deeply rooted in the Olympic ideal and sits at the heart of sports ethics. Fair play extends beyond following written rules to respecting unwritten rules. It includes unconditional respect for opponents, fellow players, referees and fans. Soccer's Laws of the Game give each match's referee full authority to enforce the Laws. The Queensberry rules for boxing, first adopted in 1865 by some accounts and 1867 by others, required gloves, three-minute rounds with one-minute rests, and no wrestling or clinching.

In Brams's view, a division should be considered fair only if two people think they both got pieces of the same value. "I cut, you choose" is an old, standard way for two people to split a cake. The person who cuts makes two pieces they think are equal. The other person picks the slice they like best. Cake is not the same all the way through, so two pieces of the same size can be worth different amounts to different people. In another method described by Science News Explores, each friend says where they would cut and someone else divides the middle section between them.

Shaw and Olson (2013) report that 6- to 8-year-olds are more concerned with making the outcome of a resource distribution equal. They also note that children are perfectly willing to share unequally by giving more to the person with fewer resources. In seven societies, pairs of children were randomly put in a disadvantageous or advantageous position. Children rejected the disadvantageous position as early as age four and as late as age 10. In a 2003 Emory study, capuchin monkeys given cucumber for a token trade completed 95 percent of trades when partners also got cucumber. They completed only 60 percent when partners got grapes. In a 2016 PLoS One study, dogs refused to continue giving their paw when only their partner was rewarded.

Some parts of fairness look the same around the world, while others change with local customs. A guide to teaching young children about voting says the essence of a fair vote is that one person means one vote. In a majority vote, the choice with the most votes decides the outcome. After a vote, someone may be unhappy with the result; that is part of voting. Greater Good educators note that students who treat others fairly are often more well-liked. A child can keep a few special things just for themselves, and does not have to share everything. A parenting educator argues that real fairness is not about everything being identical but about meeting individual needs.

Words to know

• arbitrariness: random choice
• ignorance: not knowing
• lots: chance draws
• impartial: not taking sides
• referee: game judge