Creating a law to restrict the personal use of cars and requiring everyone to use public transportation would be as unthinkable as revising the laws of gravity. There are some forces so fundamental that we have no control over them.
What makes this analogy unsound?
1 Societies do have control over the laws they make.
2 Controlling personal car use takes minimal effort.
3 Rules and laws always have some exceptions.
The correct answer is 1.
The analogy does not accurately reflect the concept it is trying to illustrate. The laws of gravity are fundamental and beyond human control, whereas the creation and revision of laws is within the control of societies. Comparing the two situations is therefore unsound because they are fundamentally different concepts.