The statement above is Newton's first law of motion, also known as the law of inertia. This is because it is a factual statement based on observations, and it describes the behavior of objects in motion or at rest when no external forces are acting upon them.
Newton's laws of motion are a set of fundamental principles that describe the behavior of objects in motion, and they are widely accepted as one of the most important contributions to physics. The laws explain and predict the motion of objects and have been tested through observations and experiments, making them a well-established theory of motion rather than a hypothesis.
Therefore, the statement above is Newton's first law of motion because it is a factual statement based on observations, and it is widely accepted as a theory of motion.