A more thorough explanation:

Definition: Falsa causa is a Latin term that means "mistaken reason or motive." In Roman law, it refers to the falsity of consideration, which can result from several things, such as a mistaken reason for making a gift or bequest.

Examples:

• A wealthy man leaves his entire estate to his butler, believing that the butler had saved his life. However, it later turns out that it was another servant who had saved his life. In this case, the falsa causa would be the mistaken reason for making the bequest.
• A woman gives a large sum of money to a man, believing that he is her long-lost son. However, it later turns out that the man was an imposter. In this case, the falsa causa would be the mistaken reason for making the gift.

These examples illustrate how falsa causa can occur when someone is mistaken about the reason or motive for their actions. In both cases, the individuals believed they were acting for a certain reason, but that reason turned out to be false.