What is lost to us, implying with that phrasing that it was precious to us, remains precious to us after it's lost, becomes a thing. What is not (yet) lost us, what our mind still holds to be self-evident, what it recognizes instinctively, as part of its own life, as its power, attribute, extension, is not isolated from "the world", i.e. the sensory continuum, the actual, so it can not be understood as something standing by itself, it is not a concept and it does not have object-hood, by which I mean a "name in heaven", of which Platos alegory is a mystification.
When some part of our sustenance, of what sustained our personal experiene, is removed, the quantum of qualities that departs from our world, is represented to us by the precise measures of its absence. In this even what is considered pecision is also called emotion. We comprehend lack as feeling. How complex this world is, this un-world inside our real being, its paradoxical "nature" (an absence has, of course no coherent, congruent nature/essence/function) is seen in the permutations of what is combining with what was, and remains in the reason of what remains.
To shed this thingness is to give the hole to the flux, to restore being in its non-conscious, non-heavenly world of intertwining attributes, unquantified qualities, actual valuing-being of value versus abstract value - yearning.
Our human world at large is a yearning gap... and the enclosing of this gap by the enslaved potency. We, philosophers on the mountainslope can discern the edges of the enslaved, as we take distance from the meaning of heaven, this protocol whereby the machine "man" perpetuates until it sublimates enough of its enclosing and yearning to the advantage of philosophy.
For mankind to mature many men must become child.