Practical solution for a Ship of Theseus

Long time ago I had an interview for an SWE position in some automotive startup and of the questions was something like “How would you distinquish two cars?”. I said I would use ID but I saw that interviewer was not satisfied with my answer.

Later, after investigation, I find out that chassis number or VIN (Vehicle identification number) is used to uniqely identify car or distinquish two cars from each other.

So you can basically replace all parts except chassis and it will be considered the same car. If you replace chassis, then it is not the same car anymore.

Try to replace it and if police stops you they will see on your vehicle license or Vehicle Registration(in USA) that VIN on the chassis does not match the one in the document. So you will be at risk of being accused of driving stolen vehicle.

This is just one example how people can find practical solutions for age old philosophical problems.