Whose theory is often branded the "action reaction" theory?

According to Newton’s third law of motion, “To every action, there is an equal and opposite reaction.” This means that whenever an object interacts with any other object, there exists a pair of interaction forces acting on both objects. The third law of motion is also called the action-reaction law. Both the action and reaction forces act on the objects simultaneously.

The recoil of a gun is one of the best demonstrations of action-reaction forces. When a bullet is fired from a gun, the gun moves backward. The action force exerted due to firing is in a forwarding direction that causes the bullet to move ahead.

When a person sitting on a chair pushes the wall with his feet, the chair moves backward. The motion of the chair can not exist without the existence of a force. Therefore, the force responsible to move the chair is the reaction force. The reaction force is always exerted in the direction opposite to the direction of the action force. Hence, the chair moves in a backward direction.

When we walk, a significant amount of force and pressure is exerted on the ground by our feet. The ground in response exerts an equal amount of force in the opposite direction. In absence of the reaction force produced by the ground, our foot sinks. Similarly, if the action force supplied by the foot of the person is significantly higher, the reaction force can help us to jump. Hence, walking is possible because a pair of action-reaction forces act on the feet and the ground.