Motion is all about change in position over time. However, "change" itself is a relative concept. To determine if something is moving, we need a point of reference – a fixed point or object that we can use to compare the position of the moving object to.

Here's why:

* No Absolute Rest: There is no absolute "rest" in the universe. Everything is constantly moving relative to something else. Even objects that appear stationary are moving relative to the Earth, which is rotating and orbiting the Sun.

* Frame of Reference: Our perception of motion depends on our chosen frame of reference. For example, imagine you're on a train. If you look out the window, the trees seem to be moving backward. However, from the perspective of someone standing on the ground, the trees are stationary and the train is moving forward.

* Relative Motion: This means that motion is always described as relative motion, meaning the motion of one object in relation to another object.

Example:

Imagine you're sitting in a car that's parked. Relative to the car, you are stationary. However, relative to the Earth, you're moving at the Earth's rotation speed.

In conclusion: We can't describe motion without a reference point because motion is a relative concept. To understand if an object is moving, we need to compare its position to something else that we define as stationary.