Wave-particle duality means that all elementary particles or quanta can be described not only partly in particle terms, but also partly in wave terms. This means that the classical concepts of "particles" and "waves" have lost their ability to fully describe physical behavior in the quantum range. Einstein described this phenomenon this way: "It seems that sometimes we have to use one theory, sometimes another theory to describe (the behavior of these particles), and sometimes we have to use both. We encounter a new kind of difficulty, which forces us to describe reality with the help of two contradictory points of view. Two points of view cannot fully explain the phenomenon of light alone, but together they can."
Because the types of people are too complex, it is not easy to define them in a general way. It is impossible for two people to understand each other alone, but together they can. Sometimes it's called not being able to generalize, and sometimes it's called being the same person but having different fates.