Avoiding the common wisdom fallacy: The role of social sciences in constitutional adjudication

More than one hundred years ago, the U.S. Supreme Court started to refer to social science evidence in its judgments. However, this has not resonated with many constitutional courts outside the United States, in particular in continental Europe. This contribution has a twofold aim. First, it tries to show that legal reasoning in constitutional law is often based on empirical assumptions so that there is a strong need for the use of social sciences. However, constitutional courts often lack the necessary expertise to deal with empirical questions. Therefore, I will discuss three potential strategies to make use of social science evidence. Judges can interpret social facts on their own, they can afford a margin of appreciation to the legislator, or they can defer the question to social science experts. It will be argued that none of these strategies is satisfactory so that courts will have to employ a combination of different strategies. In order to illustrate the argument, I will discuss decisions of different jurisdictions, including the United States, Canada, Germany and South Africa.