Here's why:

* Insulators are materials that resist the flow of electricity. They have few free electrons that can easily move and carry an electric current.

* Conductors are materials that allow electricity to flow easily through them. They have many free electrons that can move readily.

Paper is made of cellulose fibers, which are primarily composed of carbon, hydrogen, and oxygen. These atoms are tightly bound together, making it difficult for electrons to move freely. Therefore, dry paper does not allow electricity to pass through it easily.

However, it's important to note:

* Moisture can make paper conductive: When paper gets wet, the water molecules can act as carriers for electrical current, making the paper more conductive.

* Some types of paper can be made conductive: There are special types of paper treated with conductive materials like graphite or metal coatings that make them capable of conducting electricity.

So, while dry paper is generally considered an insulator, its conductivity can be affected by moisture and special treatments.