Good analogy but incomprehensible for my linear thinking brain. I agree causality is generally the main problem in movies with time travel and generally it has often been tried to be avoided but in this movie it is put at the center of the plot for the twist. Bold move. That is why after having watched the movie, I had this feeling of incompleteness while my poor brain try to justify the plot. Even having thought about the delayed-choice quantum eraser experiment did not help much. I need to let it go with 6.