ABSTRACT
Many people falsely assume that all definitions are either arbitrary stipulations or mere descriptions of common usage. However, some definitions serve concrete practical purposes. Consider cities. The United States once passed a law that provided federal funds for public transportation systems in any city in the United States. Many communities applied for the funds, but which of these communities were cities and, hence, eligible for funds? The government could not answer this question by citing common usage, because common usage is too vague. The government also did not want to decide arbitrarily, since that would be unfair and impossible to justify to communities that were excluded. What they did was to estimate how many communities would apply and for how much funding. Then they could calculate how far the available funds could go. They defined “city” so that their available funds could help as many people as possible. They ended up defining cities as communities with at least 50,000 inhabitants within a certain area. This definition did not describe common usage, and it was not arbitrary stipulation. It was based on practical concerns. They would have been subject to criticisms if they had defined cities too broadly (so as to include a town of 5,000) or too narrowly (so as to include only areas with over 5,000,000 inhabitants). The criticisms would have been that they exceeded the limits of common usage and also that their definition didn’t serve their practical purpose of funding as many cities as they could afford to fund. Their solution was within these limits and served a practical purpose, so their answer was reasonable.
