Petitio Principii

Today, when I went to visit my sister.I found that she is using Fallacy of Petitio Principii to teach her 2 years old daughter, jane.When she explains something to jane, she will use it because this fallacy will make her understand the words well.

For example, when my sister explains to jane about what is apple, she said "The is a red sweet apple , because it is a fruit with red skin and taste sweet."

Another example is when my brother-in-law praise Jane, he used this fallcy also.

he said " jane, you have pretty face, because you have beautiful eyes, nose and mouth."

Petitio Principii = S is true , because S is true

Red sweet apple = fruit with red skin and taste sweet

Pretty face = beautiful eyes, nose and mouth