"The key assumption is that the pattern of noise in the cause will be different to the pattern of noise in the effect. That’s because any noise in X can have an influence on Y but not vice versa."[...] "That’s a fascinating outcome. It means that statisticians have good reason to question the received wisdom that it is impossible to determine cause and effect from observational data alone." https://medium.com/the-physics-arxiv-blog/cause-and-effect-the-revolutionary-new-statistical-test-that-can-tease-them-apart-ed84a988e