It's amazing to say, recently I found that some investors are still using data indicators in the mobile Internet era to find projects. After looking around, I found that I couldn't find a single project that had been retained. So it's been three years in the AI industry, and they haven't started an AI project yet. Why is previous experience wrong? I just got some answers from reading a book today. Formal and non-formal logic, as well as probability theory, are in fact oriented to the past. Wishful thinking in the hope of using conclusions based on past data and analysis in the present to guide future decisions. Bayes' law, on the other hand, is future-oriented.