We discussed Posner’s economic analysis of the right to privacy. This comes in two parts.
The primary economic case for giving legal, enforceable rights to keep information private concerns information that is costly to acquire. If this information could not be kept secret from others, no one would have an incentive to go to the trouble of finding it: others could just sell the fruits of their labor. Everyone is better off with the system of property rights. Those who can get the information are willing to do so and those who would pay to buy it from them can do so as well.
Personal information, by contrast, is usually used to deceive others, according to Posner. To put it another way, it is used to get people to buy things they do not want, like employees with criminal records.
Finally, there is an economic case for protecting communication. Without it, it is harder to get candid information and opinions from others.
Posner maintains that courts have recognized privacy rights in ways that mirror the economic analysis of privacy. For example, it prohibits industrial surveillance that simply forces firms to take expensive counter-measures but it does not prohibit ways of acquiring information that do not provoke counter-measures. Hence aerial surveillance, which would only get other firms to hide their factories, is out while reverse engineering a product, which would not cause similar counter-measures, is OK.