As Chomsky was developing his computational theories, he was simultaneously proposing that they were rooted in human biology. In the second half of the 20th century, it was becoming ever clearer that our unique evolutionary history was responsible for many aspects of our unique human psychology, and so the theory resonated on that level as well. His universal grammar was put forward as an innate component of the human mind — and it promised to reveal the deep biological underpinnings of the world’s 6,000-plus human languages. The most powerful, not to mention the most beautiful, theories in science reveal hidden unity underneath surface diversity, and so this theory held immediate appeal.