Pretend you're the policeman who stopped him driving 10 miles over the speed limit. What box will you check on your report when it asks for a description of the man driving the car?
Thai African Indian American. They do have a box for that one, don't they?
Thus in Brazil, people will often have a full brother or sister who is considered to be of different color. In America we historically force people into one or the other "race" whether they fit or not.
This either/or dichotomy has actually had some beneficial effects, in the long run. The logic of the Declaration of Independence made the slavery of blacks impossible unless you could somehow remove their humanity. OTOH, once you recognize their humanity, there is no logical place to stop short of recognizing their full rights as equals.
Societies, like Brazil, which are descended from feudal cultures, are able to recognize a range of in-between groups and statuses which just don't fit into our black/white, slave/free, inferior/equal categories.