[bodge5000]

Defining tall doesn't matter so much, a) because we have a precise measure of height and b) because we all know and fully understand that the definition of tall is completely subjective. You might say the same thing about credit, but then you also need to accept that for a lot of people will gravitate towards these mythic heroes as appropriate credit.

The problem with my wheel example is that it demonstrates the absurdity of trying to assign credit to anyone involved, but it doesn't quite demonstrate how difficult it is to even draw a rough line. Does the inventor of the abacus get credit in the creation of computer science? The discovery of electricity? And what about all the (comparatively) minor inventions and discoveries off the back of those?

As far as I can see it, it either needs to be completely subjective, or there needs to be a line. Maybe it doesn't need to be incredibly specific, although at that point some subjectivity creeps back in