The idiom "You can't have your cake and eat it" comes from Mencius' I Want Fish. The original intention is not to say that you can't have both, but to emphasize how to choose if you can't have both. There are also some good things, not too much, otherwise it will not reflect its value. Just like two tigers can't fit in one mountain, the top of the pyramid is always the rarest and most precious, which is intended to remind people how to choose when faced with trade-offs.

Mencius said, "Fish is what I want, and bear's paw is what I want." You can't have your cake and eat it. Life is as I wish, and righteousness is as I wish.

Desire also; You can't have both, and you have to sacrifice your life for righteousness. Life is what I want. I want it more than the living, so I don't want it. Death is what I hate, and what I hate is more terrible than the dead, so I bear the pain I can't avoid. If people only want life, why not use those who can have life? If people are more terrible than the dead, why not treat the sick? If you are right, you are born unnecessary. If you are right, you can make trouble without doing anything. A bowl of rice, a bowl of soup, you can live if you get it, but you will starve if you don't get it. Not only the wise have a heart, but everyone has a heart, and the sages should not be lost.

A meal, a bean and a soup, if you get it, you will live, if you get it, you will die, and if you get it, you will be blessed. Beggars disdain this. I accepted it for 10,000 minutes without arguing about propriety. What does ten thousand minutes do to me? For the beauty of the palace, for the matter of wives and concubines, for the poor, you can get me and? Township (6) is not subject to physical death, and today is the beauty of the palace; Die for yourself, not subject to it, and now be regarded as a wife; Is it right to do this in order to refuse to accept death and to help the poor? This is called the loss of humanity. "