Is the earth not a proper noun?

The questioner : You said that the earth is not a proper noun.

The Shaykh : Yes.

The questioner : I said it is not a proper noun.

The Shaykh : Yes, it is inanimate.

The questioner : Yes.

The Shaykh : It is a generic noun.

The questioner : ... it is not a proper noun.

The Shaykh : It is not a proper noun.

The questioner : Why?

The Shaykh : Because it is a generic noun. Yes, if you heard "a person" with "earth" or "a woman" with "earth," it would become a proper noun.

The questioner : Okay, if it were a proper noun for something inanimate, would it be called a proper noun or not?

The Shaykh : It is called a proper noun, but it is not pluralized with the sound feminine plural; it is pluralized with the masculine sound plural.