There's no such thing as "human rights" in general by that standard. You can't point to a physical object or some quantum of energy and say, that's a human right that you can measure. Human rights are something we decide on as a society, and if society decides that there is a human right to a set amount of working hours, then it becomes a human right.

The argument that there never has been such a thing is basically arguing that we should stop all progress. That nothing that doesn't already exist should ever be created