Let us take the law of gravitation as an example.

Its formulation is as follows: Two material bodies attract each other with a force proportional to the product of their masses and inversely proportional to the square of their distances.
In this statement the bodies are supposed to be small enough to be treated as material particles in relation to their distances; and we need not bother further about that minor point.

The difficulty to which I want to draw your attention is this: In the formulation of the law one definite time and one definite space are presupposed.

The two masses are assumed to be in simultaneous positions.
But what is simultaneous in one time-system may not be simultaneous in another time-system.

So according to our new views the law is in this respect not formulated so as to have any exact meaning.