The discussion explores the physical principles behind why a piece of paper typically cannot be torn into three pieces by pulling on both sides. It highlights that the stress concentration near a crack tip influences crack propagation, which is relevant in material science. An example is given where adding weight, like a coin, to the center of the paper can allow it to be torn into three pieces due to increased inertia. The lightness of the paper's center piece usually causes it to move with one side, preventing a clean three-way tear. Ultimately, the interaction of forces and material properties determines the tearing behavior.