For the native observer within a particular culture, emic units are considered to differ from one another in relation to everyday behavior. A boy is not a girl. A mountain is not a valley. Yesterday, viewed from now, is not today. Youth is not age.
Emic units contrast.
It is easy for us to differentiate an airplane from a wheelbarrow. But it is not easy for some of us to differentiate a copperhead snake from a rattler, even though it may be simple for people who are used to avoiding the both of them. They need to be seen as emically different, for survival, in some contexts. I was surprised. I would agree that there is no way to completely eliminate our own observer impact on our own relation to the universe.