Object Permanence

Micah is approaching the age where he will begin to develop object permanence, the concept that something still exists even if one cannot see it. The whole idea strikes me as odd. It seems like we develop this thought and then spend the rest of our life learning that this is not actually true. Perhaps what we call separation anxiety, which tends to accompany this, isn't so much a fear that one will not see another again, but a premonition that this concept is too good to be true.