"Everyone has a key to open the door of heaven, and this key can also open the door of hell." So, what is the value of the key to heaven? If we can't tell whether a door leads to heaven or hell, then the key in our hand is a dangerous thing. But this key does have its value-without it, we can't open the door of heaven; Without it, even if we clearly distinguish between heaven and hell, we are still helpless. It can be inferred that although scientific knowledge may be abused and cause disasters, its ability to have a great impact is itself a kind of value.

Said by: richard feynman, why do you care about other people's opinions? 》

It is extremely important for scientists to experience ignorance, doubt and uncertainty all day. When a scientist does not know the answer, he is ignorant; When there is a guess in his mind, he is uncertain; Even if he is sure, there is always room for doubt. It is essential for any development to admit your ignorance and leave room for doubt. Scientific knowledge itself is a collection with different credibility: some are completely uncertain, some are relatively certain, but nothing is completely certain. Scientists are used to the above situation, and they will naturally question and admit their ignorance because of uncertainty. But I don't think most people understand this. In history, science and authoritarian authority fought repeatedly before gradually winning the freedom we questioned. What a long and arduous battle this is! It finally enables us to ask questions, question and be uncertain. We should never forget history, lest we lose the freedom we strive for.

Said by: richard feynman, why do you care about other people's opinions? 》

The main purpose of teaching this course is not to prepare you for some kind of exam, or even to prepare you for working in the industrial or military sectors. I actively want to tell you how to appreciate this wonderful world and the way physicists look at it. I believe this is a major part of modern real culture.

From: Feynman Lecture on Physics in richard feynman.

I have a friend who is an artist. I really don't agree with some of his views. He will pick up a flower and say, "look, how beautiful!" " "Yes, the flowers are beautiful, so am I." He will then say, "You see, as an artist, I will appreciate the beauty of flowers; As a scientist, you can only analyze this flower layer by layer professionally, which is boring. "I think he is talking nonsense. First of all, I believe he thinks the flowers are beautiful, and others and I can see them. However, I may not have his exquisite aesthetic feeling, but there is no doubt that I know how to appreciate the beauty of flowers. At the same time, I can see more things: I will imagine the cells in the flowers, and the complex reactions in the cells are also beautiful. I mean: beauty is not entirely in this square inch, beauty also exists in a smaller microscopic world, and the internal structure of this flower is also beautiful. In fact, some evolutionary processes are very interesting. For example, some flowers start to be colored to attract insects to pollinate. This means that insects can also see colors.

Said by: richard feynman, The Joy of Discovery.

With the deepening of research, we will find that what science expresses is not right or wrong, but different degrees of certainty.

Said by: richard feynman, The Joy of Discovery.