I mentioned this elsewhere to @Wayfarer. I think it fits in here. As a thought experiment — somewhat motivated by my reading of Gerson — let us imagine Plato’s work as focused on the intelligibility of the world.
Let us imagine an “foundational” investigation into the structure that enables any and every “surface” investigation. In my view, this include what is so basic as to even be boring — at first. We live in a world of common objects that we discuss.
"Here comes Socrates again. "
“Let us discuss ( the same ) ( concept of ) Justice again.”
Let us discuss. The sounds from our mouths ( words ) somehow “access” or “touch” these common public objects, be they obviously sensory or otherwise.
What does it mean for inquiry to “make sense” of the world ? In a peculiar sense — and almost tautologically — the essence of the world is sense. But I don’t see this “sense” or “significance” as “internal stuff.” I see Socrates himself, flesh and blood, walking over. My “direct perception” of the world is of a world of enduring intersubjective entities.
I do not sincerely doubt that what I perceive is also there for others, excepting rare cases that get labelled as “hallucinations,” etc.
So the world is there as a common world of “wholes” or “unities.” While sensation is “continuous” in some sense, this “sensory-affect continuum” is always already organized into a system of “discrete” or “digital” objects.
I don’t mean anything fancy here. We can count that there are seven red apples on the table. I am tempted to understand “idea” in Plato to point at the unity of each apple.
The apple does not obviously have some exact boundary. My friend Bob is nearsighted, but he is close enough to count 7 apples also, though they are blurrier for him than they are for me.
We have no doubt that we are discussing and counting the same apples. We have not yet concerned ourselves with the exact spatial boundaries of the apples. Perhaps we do not agree on the chemical makeup of these apples. But we can’t argue about and come to a consensus about the boundaries or make-up of the apples if we don’t already “co-intend” the same apples.
I have also been trading words with Bob. I make sounds for him and he makes sounds back for me. Those sounds are words that are fundamentally repeatable. As with the apples, I don’t know exactly how my words are there for Bob in sensory terms, but I trust that he recognizes their “form” in the sense of what word was spoken. Here Saussure’s “sound-image” is useful.
In short, the “formal” or “ideal” element that makes the world “countable” and capable of repetition looks necessary for inquiry. I suggest that Plato’s “idea” is aimed that this formal component of the world.