Even this is a metaphor, for the sun is an object that may be compared to other objects, whereas the Ideas are not visible to us directly, but only through a comparison that we make between objects. An Idea is really a different kind of object. An “object”; an Object. – No object at all. They are not objects for comparison, not objects of comparison. They are rather what the comparison reveals, and what makes the comparison possible—the transcendental condition for the comparison: what animates the comparison, what gives the point to the comparison, the sense of the comparison. It is what imbues normativity in the comparison, what turns the previously inert objects into objects compared.
So why do we have this tendency to think of Ideas as objects? – One reason, perhaps, is that although rare (which contributes to their elusiveness and mystery), we have meaning-experiences: we sometimes experience how a concept makes contact with reality, thereby shedding a new light on it. – “It is not friendship if you don’t let it change you.” – We can experience how the concept (the Idea), Friendship, is making contact with the reality of our lives. It is as if it has its own power, its own efficacy. – But of course, this is just “as if”; it is only a metaphor.
So, it seems, for Plato, the absolute sense of “seeing” is unavailable to us. This is the sense in which Ideas are literally seen. We have available to us a derived, indirect, sense of “seeing Ideas”: seeing ideas through the medium of objects—literally seeing objects. We also have a metaphorical sense of directly seeing Ideas, which itself depends on the derived sense of “seeing” in that it treats the Ideas as objects.