The Brethren of Purity were an independent philosophical and scientific movement that existed around 1000 years ago in the Middle East. Their main goal was to understand God and discover the secrets of the universe. In order to do this, they wrote a series of books containing philosophical and scientific ideas. The books were written in a very simple, clear language, so that anyone could understand them. The Brethren of Purity believed that knowledge should be shared freely and that intellectual pursuits should be open to all. They thought that knowledge could help people to be better and more compassionate. They encouraged people to be tolerant of different beliefs and worldviews, even if they disagreed with them. The Brethren of Purity wrote their books to share their knowledge, ideas, and beliefs with everyone, so that everyone could benefit from this knowledge.