Probability, prior probability and Posterior Probability

For many people, these concepts are clear and vague. The following is a vivid illustration.

For God, everything is definite, so probability, as a learning existence, exactly proves human ignorance. Fortunately, humans are still smart enough. We are not at risk because things are random. We decide our actions based on the possibility of things. For example, before a person grabs a bank, he must have repeatedly considered various possibilities. If people wait until everything is confirmed, you may not be able to do anything, because almost everything is random.
There are n possibilities for one thing. We are not sure which one will happen because we cannot control the occurrence of the result. Many factors that affect the result are out of our control, these factors affect the mechanism of the results, or we do not know, or are too complicated to exceed the computing power of our brains or computers. For example, we are not sure whether to get the front or back of a coin because we are insufficient to use some physical equations to solve this problem. For another example, you cannot determine that you can score 88 points at the end of the course, because you are not the one who gives questions or grades.

What happened in the past was actually definite, but it became random because of our ignorance. We dug out a piece of porcelain from somewhere. It may be Confucius's night pot, or it may be Qin Shihuang's tableware, it is also possible that the broken teapot of President Lin's house has been buried in this place from his house to the garbage station.

Therefore, probability is essentially ignorance, rather than being random.

You dug around the playground with a hoe and suddenly found a dark room. What is the scenario? It should be said that everything is possible. You can make some likelihood judgments based on what your brain has stored, for example, "black inside ". It is unlikely that "bin Laden plays mahjong here" is found ". There are infinite possibilities, there may be a murderer, or a viper ,....... Your understanding of the possibility of each scenario is probability distribution P (AI ). Such a probability is a prior probability.

Whether or not you can hear a dog's name is random. Your probability is P (Y). (Y indicates that you will hear a dog's name) is also a prior judgment.

If you do hear a dog's name next, although you are not sure about the situation in the cave, there will certainly be a new judgment: "bin Laden eats dog meat while playing mahjong", "a few dogs are playing mahjong", "A dog misses another dog and keeps a recording here "....... You have also thought of these scenarios (one of AI) before, but now, after you hear a dog call, your probability judgment has changed, your current judgment is called posterior probability P (ai | Y ).
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The possibility of this occurrence is a prior probability.
Something has happened. The reason for this is the possibility of a factor, which is the posterior probability.