The origin of language in the human species is a widely discussed topic. Despite this, there is no consensus on ultimate origin or age. Empirical evidence is limited, and many scholars continue to regard the whole topic as unsuitable for serious study. In 1866, the Linguistic Society of Paris went so far as to ban debates on the subject. That prohibition remained influential across much of the western world until late in the twentieth century. Today, there are numerous hypotheses about how, why, when and where language might first have emerged. It might seem that there is hardly more agreement today than there was a hundred years ago, when Charles Darwin's theory of evolution by natural selection provoked a rash of armchair speculations on the topic. Since the early 1990s, however, a growing number of professional linguists, archaeologists, psychologists, anthropologists and others have attempted to address with new methods what they are beginning to consider 'the hardest problem in science'.