Destiny is the uniqueness and irreversibility of time. There are many factors that affect the development of things, but time and opportunity are only given once. If any factor changes, the development of things will also change, and time is only unique and irreversible. People don't know what it's like when that factor doesn't have an impact. That's fate. For example, now that you have seen these words of mine and you have your thoughts, you may have discussed these contents with your classmates and friends, and you may have had a fight because of the discussion; but there is no way for us to assume that you have not seen these words of mine. After that, you and your friends will not talk about these contents, you will not have those conversations, and there will be no fights or quarrels. Then the development of things may lead in another direction! This is fate and time. Uniqueness and irreversibility.