Human intelligence is arguably not even truly ordinal, let alone cardinal. No one who reasonably understands human intelligence believes it's as simple as a normal distribution. IQ is defined as a normal distribution but that doesn't mean the difference between 100 to 110 IQ is comparable to the difference between 140 and 150 IQ. If you boil "human intelligence" down to nothing more than IQ, sure, but in reality there's no such thing as a mean here and median is tenuous as well.