>>17759623
Plato's epistemology, or his theory of what knowledge actually is, was what we now call "exaggerated realism."
Basically, he thought that the way we "learn" things is not best described as "gaining" new knowledge, but he thought "learning" is actually a process of remembering eternal truths that we already knew in our previous existence before we were born.
He was also careful to distinguish opinions about facts that can change over time, versus eternal, unchanging truths. When we learn truths, we simply remember, "oh yeah, that is true isn't it" as though it was some locked knowledge of truth that was always buried in our subconscious that we successfully brought to the surface, and that's how we gain knowledge.
Plato advocated for a process that he called dialectic, which simply means going through a kind of drawn-out process of talking about things such as you find in Plato's dialogues. In a dialectic, true facts are that which can withstand sustained questioning, and that which is false falls away when it is revealed to not hold up to sustained scrutiny. This type of dialectic is considered to be a process of intellectual honesty, and it is in line with the principles that Socrates stood for.
Plato in particular held that our knowledge of unchanging truths (which we can "learn" or "recover" through dialectical means) really comes from a completely separate reality of unchanging forms. The analogy of the cave is meant to represent how that separate reality relates to the physical world of change.
In the physical world, particular objects can change or lose their form over time. This is represented by the shadows on the cave wall. Observed properties of particulars that hold true today might become false later. To him, these flickering and shifting imperfect shadows that we see are just transient reflections of what exists in the world of unchanging forms, where objective and unchanging "truths" exist, which we can learn about through dialectic.
