All learning is remembering: the soul was omniscient before birth, and knowledge is the painful process of digging it back out — culminating in the mystical vision of the Good.
Source: YouTube (42:25) Links: Series Index, Episode 9: Plato’s Metaphysics, Episode 5: Pythagoras
Plato established in Episode 9 that the Forms constitute a completely different world — non-material, not in space, not in time. But here we are, on earth, trapped in bodies, limited by senses. How do we ever come in contact with the Forms?
Plato answers: by thought. But how does thought down here reach the Forms up there — especially since “up” and “down” are just metaphors, because the Forms aren’t anywhere?
The answer was already implied in last week’s arguments: we must have been in contact with the world of Forms prior to this life. Plato adopts intact the Pythagorean/Orphic view — the wheel of birth, successive reincarnation, the ultimate goal being escape from the cycle.
Before birth, our souls lived among the Forms and knew everything — were, in fact, omniscient. But when the soul was thrust into a body and immersed in the Heraclitean flux, it suffered what a modern psychologist would call a birth trauma. All that knowledge was driven into the unconscious. It’s still there, but buried.
Therefore: what we call “acquiring knowledge” is not acquiring anything new. It is a process of digging out from your unconscious what is already there. Knowledge is reminiscence — anamnesis in Greek.
Peikoff offers the analogy he was taught when he first studied Plato:
Imagine you find an old faded yearbook, 20 or 30 years after college. Your grandson is jostling it, so you get only a fleeting glimpse of a faded photograph. If you didn’t know the man in the photo, that corrupt, imperfect, flickering stimulus would give you nothing. But because you did know him well — even if you’ve forgotten completely — that tiny stimulus is enough: “Oh yes, Jones! I remember him, I haven’t thought of him for years.”
For Plato, all knowledge works this way. You see a few horses and say: “Ah yes — horseness. Now it comes back to me.”
The senses are definitely needed in the early stages of knowledge — but not to teach us something new. They serve only as a stimulus to jog our memories. After this initial period of stimulation, knowledge thereafter is a matter of looking inward, not outward — turning away from the physical world to introspection, because we have in us all the basic truths, laws, and concepts. We find them and proceed to deduce their consequences logically, quite apart from any further sensory observation.
With Plato, rationalism gets its fully worked-out form. The early pre-Socratics (Heraclitus, Parmenides) were rationalists who said reason trumps the senses, but if you asked them how reason operates apart from sensory data, they had no answer.
Plato’s answer: reason can acquire knowledge apart from the senses because we are born with innate ideas.
From Plato onward, rationalism means: the epistemological theory that knowledge is acquirable solely by reasoning from innate concepts, and that sense perception is in principle dispensable (except as a stimulus).
Note: Peikoff flags that this definition holds for rationalists up through the 18th century. Kant introduced a significantly different version that does not rely on innate ideas — a distinction to be explored later.
In the dialogue Meno, Socrates demonstrates innate knowledge: bring in an uneducated slave boy, and through questioning alone — everything interrogative, nothing declarative — the boy arrives at a complex geometric theorem. Moral: he had it in him all along; he just needed to be reminded.
Peikoff’s assessment: not very convincing. Critics for centuries have pointed out that Socrates was feeding the boy information in the form of questions. “Don’t you see that the angles of a triangle add up to 180 degrees?” — “Yes.” That’s telling, not eliciting.
The Phaedo offers four proofs for the immortality of the soul. The strongest was implied in last week’s arguments: if the soul existed prior to the body, it can exist after — because the key move is establishing the soul’s independence from the body.
The other three proofs are, in Peikoff’s assessment, very poor arguments — he declines to spend time on them.
Plato describes a line divided into four segments, representing the ascent from ignorance to complete mastery of the universe.
The lowest stage. You are wholly ignorant, confused, unenlightened. You take all superficial appearances at face value. You cannot distinguish dreams from physical things — if you dream someone hits you, you wake up angry. You see a mirror reflection and think it’s another person. You’re bombarded with an unidentified stream of sensations.
Moral counterpart: The mentality of an animal — desire and act without any question of right or wrong. Or: the Sophist who does the same as a matter of principle.
You’ve learned to distinguish fact from fancy, physical objects from dreams and images. You’ve risen to the level of scattered empirical observations and crude, approximate rules of thumb. But you don’t know why any of it holds true, so you can’t be certain it will continue.
Peikoff’s examples:
Moral counterpart: The average man who has absorbed rules (don’t kill, don’t steal, don’t lie) but couldn’t for the life of him say why or prove they’re universal.
Note: your opinion might be right — but even right opinion is still only opinion, not knowledge.
This is where science begins. Having gone through the sensory stimuli of the preceding stages, you can now turn away from the physical world entirely and focus on the Forms. Every time you grasp a Form, it illuminates and makes intelligible everything you’d observed at the lower levels.
Peikoff’s horse example across three stages:
Or for mechanics:
The general principle: the abstract always explains the particular. The universal gives you the reason for the particular.
But we’re still not at true knowledge. At this stage, we hit the blank wall of the axioms of the various sciences — and they are unvalidated assumptions. The whole structure is precarious.
We grasp the Form of the Good — the pinnacle — and are able to reason down the whole chain, showing that everything discovered in the ascending stages follows deductively from the Good. At this point we have true understanding of the universe. We “hit the epistemological jackpot.”
Peikoff, channeling Plato on the experience: “When you hit the Form of the Good, it’s so overwhelming, so revolutionary, so soul-penetrating that no one could possibly be mistaken.” The Hollywood movie about falling in love, where bells go off — “that is nothing compared to what goes off when you hit the Form of the Good.”
Plato illustrates the four stages with the most famous philosophical parable ever written, from the Republic:
The Setup: Imagine you are prisoners in a dark, gloomy underground cave, chained at the neck and ankles since birth, able only to look straight ahead at the wall. Behind you, unseen, people carry objects in front of a fire, casting moving shadows on the wall. The shadows are all you’ve ever known — you take them as reality. You award PhDs to the best shadow-detectors. You make them president. They’re the experts at dealing with “reality.”
The Release: One prisoner is freed. It’s painful — he’s been sitting for years. The firelight is blinding. But his eyes adjust, and he sees the actual objects and the fire: “So this is what’s really going on. I was just looking at shadows.”
The Ascent: He’s led up a long tunnel to the earth’s surface. He emerges into a fantastic new realm — variety, beauty — completely overwhelming compared to the dingy cave. This, he seizes, is what’s really real. The cave world is a meaningless appendage. At first, even the surface is blindingly bright. But eventually he looks up and sees the Sun — the source of all light, all energy, all life. He’s reached the end of his journey.
The Return: He wants to stay in the sunlight, but feels it his duty to return and free his fellow prisoners. He stumbles back down (he can’t see in the dark anymore). He finds the prisoners arguing excitedly about some shadow and rushes in: “Forget this nonsense! I’ve seen true reality!” They ask what it’s like. He says: “I can’t tell you — it’s incommunicable. You’d have to see it for yourself.” The prisoners think he’s crazy. They give him a sanity test (can he deal with shadows?). His eyes aren’t adapted to the dark; he fails. They put him to death.
An obvious allusion to what the masses did to Socrates.
The Mapping: | Cave Element | Platonic Meaning | |—|—| | Shadows on the wall | Stage 1 (imagining) — images | | Physical objects behind the prisoners | Stage 2 (belief) — physical world | | The surface world | Stage 3 (thinking) — the Forms | | The Sun | Stage 4 (knowledge) — the Form of the Good | | The prisoners | The masses of mankind | | The freed prisoner | The philosopher | | Death of the returned prisoner | The death of Socrates |
Peikoff draws the political implication immediately: if the crucial knowledge needed to live is painful, difficult, incommunicable, and requires a mystical insight that only a very few will ever achieve — then only those few are qualified to tell men how to live and to govern their affairs.
This is the epistemological base of Plato’s politics (coming in a later episode). And it is “the first instance of an invariable law of philosophy: mysticism leads to dictatorship.”
The Cave allegory also dictates Plato’s ethics. The goal of the moral man is to escape from the cave — to reach the higher world of beauty, truth, and sunlight. His attitude to this world: disdain, dislike, yearning to get out.
The body is doomed to remain in this world. Only the soul can go to the world of Forms. And this it does when man dies. Death is the ultimate goal.
Peikoff quotes the Phaedo directly:
“Ordinary people seem not to realize that those who really apply themselves in the right way to philosophy are directly and of their own accord preparing themselves for dying and death. If this is true, and they have actually been looking forward to death all their lives, it would of course be absurd to be troubled when the thing comes for which they have so long been preparing and looking forward… It is a fact that true philosophers make dying their profession.”
Why not commit suicide? Same answer as the Orphics before and the Christians after: God giveth, God taketh away. Suicide is prohibited. But during life, you can free the soul as much as possible from domination of the body — live an ascetic life.
From the Phaedo: The philosopher despises food, drink, sexual pleasure, smart clothes, bodily ornaments. He keeps his attention directed away from the body and toward the soul. “The philosopher frees his soul from association with the body so far as is possible, to a greater extent than other men.”
The parallel is explicit: just as bodily senses deceive us in epistemology, so bodily desires corrupt us in ethics. Both knowledge and virtue require leaving the cave.
Peikoff’s modern connection: the hippies of the 1960s shared this basic attitude — anti-materialism, indifference to the body, belief in a transcendent reality grasped by mystical vision. The only difference: “the key to the mystic vision is not 40 years of higher mathematics but one dose of LSD.” Chemistry replaces mathematics as the supreme key, but the philosophy is identical.
“How did we grasp universals before birth?” A perfectly good question with no answer. The perfect Man as a Form isn’t physical — it doesn’t have a head, just “head-ness.” How do you “see” that? Plato’s epistemology simply moves the question back one step. You can’t get concepts in this life, so you got them in another — but then how did you get them there? “You got them somehow.” This is always true of reversions to supernaturalism: “Where did the world come from?” “God.” “Where did God come from?” — and you’re back where you started.
“Does Plato hold there are no degrees of truth?” Ultimately, yes: either you know the Form of the Good (omniscience) or you don’t (not true knowledge). But he makes practical distinctions — a scientist who doesn’t know the Good still has vastly more than a baby.
“Why the Good and not the Bad?” No answer. But Peikoff notes that Platonic teleological optimism is “infinitely healthier” than the alternative — Schopenhauer’s metaphysical pessimism, which holds that everything happens for a wicked purpose and the goal is to extirpate the entire universe.
Objectivist response (Peikoff): Knowledge is contextual. You can be certain within the context of available evidence and expand accordingly. You don’t need to know the latest biology to know man is mortal; you don’t need Newton to know the sun will rise tomorrow. This will be developed further with Aristotle.
The Divided Line is a genuinely insightful epistemological model. Strip away the two-world metaphysics and the four stages describe something real: raw confusion → empirical rules of thumb → theoretical explanation → unified understanding. Modern philosophy of science recognizes essentially the same progression: data → empirical regularities → theoretical laws → grand unified theories. The garage mechanic vs. theoretical physicist example is perfect — it captures the difference between knowing that and knowing why in a way anyone can grasp.
The Cave allegory is one of the greatest pieces of philosophical writing. It works on so many levels simultaneously: metaphysical (shadows vs. reality), epistemological (opinion vs. knowledge), ethical (comfort vs. truth), political (masses vs. philosopher-king), and existential (the pain of enlightenment, the loneliness of the returned prophet). That it also serves as a eulogy for Socrates gives it emotional force. Peikoff’s telling is lively — the PhD-awarding shadow-experts, the sanity test, “they did not have New York weather” — and captures Plato’s own literary genius.
“Mysticism leads to dictatorship” is a powerful thesis. If the highest knowledge is incommunicable and achievable only by a mystical elite, then rational persuasion is impossible and governance must be paternalistic. This pattern recurs: Gnostic sects, the medieval Church, Hegelian state-worship, Marxist vanguardism. The epistemological structure (a truth too profound for ordinary people) always generates the political structure (an elite authorized to impose it). Peikoff identifies this at the source.
The “move the question back one step” critique is devastating. Peikoff is at his sharpest here. How do we know the Forms? We knew them before birth. How did we know them before birth? “Somehow.” This is the same regress as every supernatural explanation: the physical world needs a creator → God → but who created God? → “He just is.” Plato has explained nothing; he has relocated the mystery. And the relocation makes it worse, because now the mystery is in a realm we can never investigate.
The Meno slave boy is philosophical theater, not proof. Peikoff is right that Socrates was leading the witness. But there’s a deeper issue: even if the boy had arrived at the theorem independently, this wouldn’t prove innate ideas. It would prove that humans can reason logically from presented premises to conclusions — which is just what Aristotle will call deduction. You don’t need pre-birth omniscience to explain why someone can follow a logical chain.
Plato’s all-or-nothing epistemology creates an impossible standard. Either you know the Form of the Good (omniscience) or you don’t have true knowledge. This makes knowledge unattainable for all practical purposes and hands the Sophists a victory by default — if virtually no one can achieve knowledge, then virtually everyone is stuck in the cave of opinion, exactly where the Sophists said we were. Plato set out to refute skepticism and ended up confirming it for everyone except a mystical elite.
The philosophy-as-preparation-for-death passages are extraordinary. They read as proto-Christian asceticism — and indeed, this is exactly how the Church Fathers read them. Augustine, the most important Christian philosopher before Aquinas, was a Platonist before he was a Christian, and his conversion was partly a matter of finding in Christianity the institutional embodiment of Platonic ethics. The Phaedo passages Peikoff quotes could appear in a medieval monastic rule without alteration. Plato’s influence on Christianity’s soul/body hostility is arguably his most practically consequential legacy.
On innate ideas: Rejected by Aristotle, revived by Descartes and Leibniz, attacked by Locke (“the mind is a blank slate”), seemingly killed by empiricism — and then resurrected in new form by Chomsky (innate linguistic structures), evolutionary psychology (innate cognitive modules), and Bayesian cognitive science (innate priors). The modern consensus is neither Plato nor Locke: we’re born with something (cognitive architecture, learning biases, perceptual primitives), but not with propositions or concepts already in place. Plato was wrong about the content but may have been right that the mind brings something to the table that experience alone doesn’t supply.
On the Divided Line: The four-stage model is essentially correct as a description of intellectual development, stripped of the two-world metaphysics. Every working scientist recognizes the progression from data-collection to theory-building to seeking deeper unification. The disagreement is about whether the endpoint (the Form of the Good / a Theory of Everything) exists and is achievable — and whether it requires mystical insight or just more of the same empirical-theoretical work.
On the Cave: Immortal. It has been reinterpreted in every era: as an allegory of Christian salvation, of Marxist false consciousness, of media manipulation, of the simulation hypothesis, of social media filter bubbles. Its enduring power comes from the structural insight that what we take to be reality may be a projection of something we can’t see from where we’re standing. This is unfalsifiable — which is both its strength (it can always be applied) and its weakness (it can never be tested).
On asceticism: Enormously influential for 2,000 years, now in full retreat. The modern West has decisively rejected the soul/body split — bodily pleasure is no longer considered intrinsically corrupting, physical health is valued, and “this-worldly” has lost its pejorative connotation. But the ascetic impulse hasn’t disappeared; it has been secularized — into minimalism, digital detox, fasting protocols, anti-consumerism. The form changes; the structure (physical renunciation as path to higher clarity) persists.