Materialism, skepticism, and idealism as the three enduring approaches — with the atomists launching mechanistic determinism and the primary/secondary quality distinction.
Source: YouTube (49:40) Links: Series Index, Episode 5: Pythagoras
Peikoff opens by framing everything that follows as the first systematic attempts at complete philosophies — not just individual insights but overall approaches. Three kinds that were formulated in Greece and endure to this day:
| Approach | Definition | Pre-Socratic Root |
|---|---|---|
| Materialism | Reality is basically matter in motion; non-material phenomena reduce to physical terms | Thales (water = matter, though he didn’t grasp the implication) |
| Skepticism | No objective or certain knowledge of anything is possible | Heraclitus (Cratylus stopped speaking — nothing to refer to) |
| Idealism | Reality is basically non-material; the material world is a byproduct of something deeper | Pythagoreans + Parmenides + Heraclitus → Plato |
Note: these are not the only possibilities. Aristotle fits none of them, and neither does Objectivism.
The atomists emerge from a broader movement called pluralism — a second attempt (after the Pythagorean two-world solution) to reconcile Heraclitus and Parmenides.
The pluralist concessions:
The reconciliation: abandon monism. Instead of one world-stuff, posit many — each internally unchanging (a miniature Parmenidean universe), but allowed to move (change position). All other kinds of change reduce to locomotion — rearrangement of eternal stuffs in new combinations. “Smash Parmenides’s One into a bunch of separate little stuffs.”
Empedocles (490–435 BC): Four root elements — earth, air, water, fire. Everything else is combinations and rearrangements. Clever but not worth dwelling on.
Anaxagoras (born ~500 BC): Exposed Empedocles’s problem — new qualities still appear when elements combine. Banana taste, chalk texture, hair color — these are different from earth/air/water/fire. If nothing truly new can come into existence, you need as many irreducible stuffs as there are types of things: tomato-stuff, banana-stuff, flesh-stuff, hair-stuff… tiny “seeds” of everything are in everything, too small for senses to detect.
This is a total dead end. Thales wanted to find unity in diversity (“the one in the many”). Anaxagoras ends up with irreducible diversity — the many as fundamental, no unity, no explanatory power. It would be the end of science.
Enter the atomists — Leucippus (6th c. BC, almost nothing known) and Democritus (460–360 BC) — with the move that transforms everything.
The key distinction: qualities vs. quantities.
| Qualities (subjective) | Quantities (real) |
|---|---|
| Colors, sounds, odors, tastes | Size (extension) |
| Temperatures, textures | Shape (triangular, rectangular…) |
| — | Motion/rest (and rate) |
| — | Number (how many particles) |
The argument: If qualities are real, you’re stuck with either Empedocles (some real, some not — but then new ones appear, violating Parmenides) or Anaxagoras (all real, all irreducible — hopeless). The only escape: no qualities are real. Reality is exclusively quantitative. Colors, sounds, tastes are merely subjective effects on us — the way purely quantitative particles happen to affect human perception.
Democritus’s famous fragment: “By convention sweet is sweet, by convention bitter is bitter, by convention hot is hot, by convention cold is cold, by convention color is color — but in reality there are atoms and the void.”
The atomic theory:
How do atoms behave? Exclusively through physical pressure, impact, and mechanical reaction. The billiard ball metaphysics.
Three consequences:
On the soul: The atomists believed in soul-atoms — “fine, round, smooth, polished, mobile” particles diffused throughout the body. Consciousness = soul-atoms quivering. Sleep = temporary deficiency. Fainting = sudden exodus during the day. Death = permanent departure, after which there is no “you” left.
On the gods: They believed in gods (because people dream of them, and dreams must have counterparts in reality), but gods were also made of atoms, mortal, indifferent to humans. Effectively atheism.
Senses invalid (yet again): The senses show colors, sounds, tastes — but these aren’t real. Reason reveals atoms and the void. Same reality/appearance split as everyone before them. Still rationalists.
This atomist distinction — real quantitative properties vs. subjective qualitative effects — “never went anywhere in the ancient and medieval world” but was picked up at the Renaissance by Galileo, Descartes, Spinoza, Leibniz, and Locke, who gave it the modern name: primary qualities (size, shape, motion) vs. secondary qualities (color, sound, taste). It became the basis for invalidating the senses in modern philosophy. Peikoff flags this as a major issue to be resolved later.
Peikoff devotes substantial time to attacking mechanistic materialism:
Self-refutation: If there’s no mind capable of observing evidence and reasoning logically, then every person’s conclusions express nothing but blind mechanistic reactions. No one can claim to be guided by logic or evidence. Materialism entails skepticism about materialism itself.
Consciousness as a cognitive primary: The materialist says “I can’t find consciousness — I can crack open your head and find brain but no mind.” But this sets up matter’s characteristics as the criterion of reality and then declares anything lacking those characteristics unreal. You could do the reverse: “You can’t psychoanalyze electrons, so matter doesn’t exist.” Both are absurd. Consciousness and matter are descriptively different primaries, each known in its own way — consciousness by introspection, matter by external observation.
Two forms of materialism:
Objectivism’s position: Consciousness is real, irreducible to matter as we currently understand it, efficacious (it causes behavior), and volitional. The ultimate relationship between matter and consciousness — whether consciousness emerges from material complexity, or the two are irreducible co-primaries, or both derive from some unknown third thing — is a scientific question, not a philosophical one. Philosophy establishes that consciousness exists and is effective; science determines the mechanism.
Mechanism in physics: Objectivism accepts mechanism for inanimate nature (no teleology for rocks). Purpose is coextensive with consciousness. But specific physical laws (Galileo’s, Newton’s, Einstein’s) are scientific questions, not philosophical ones.
The pluralist logic is crystal clear. The progression from Empedocles (four elements, but new qualities still appear) to Anaxagoras (infinite stuffs, but no explanatory power) to Democritus (strip qualities entirely, keep only quantities) is presented as a problem-solving sequence where each step responds to the failure of the previous one. You can see why they ended up where they did.
The primary/secondary quality distinction is correctly identified as a time bomb. Peikoff is right that this relatively obscure atomist distinction became enormously consequential when the Renaissance scientists adopted it. Flagging it here, 2,000 years before its detonation, is good structural work.
The self-refutation argument against materialism is strong. If the theory is true, the theorist’s belief in it is just atoms rattling — not a conclusion arrived at by evidence and reason. This has been made by opponents of materialism from antiquity to the present (Plantinga’s evolutionary argument against naturalism is a modern variant) and has never been satisfactorily answered by materialists.
Peikoff’s treatment of consciousness is careful but revealing. He explicitly says the ultimate relationship between matter and consciousness is a scientific question and refuses to speculate. This is philosophically responsible. But it also means Objectivism is agnostic on the hard problem of consciousness — it establishes that consciousness exists and is efficacious but doesn’t explain how subjective experience arises from physical systems. The “cognitive primary” move (consciousness is basic, known by pointing, not reducible) is defensible but doesn’t resolve the explanatory gap.
The void as “crude violation” of Parmenides. Peikoff flags this but doesn’t dwell on it. The atomists needed empty space between atoms but had no philosophical justification for it within the Parmenidean framework they claimed to accept. This is the same vacuum problem from Episode 4, and it’s interesting that Peikoff (who agreed with Parmenides on no vacuum) doesn’t press the point harder against the atomists.
Modern physics complicates both sides. Quantum mechanics introduces irreducible randomness (violating atomist determinism), wave-particle duality (blurring the quality/quantity distinction), and the observer problem (consciousness seems to matter in measurement). The atomists were right about atoms being real but wrong about almost everything else: atoms are divisible, qualities may be as fundamental as quantities (color charge in QCD), and determinism fails at the quantum level. The billiard-ball picture is dead in physics even if it persists as folk metaphysics.
The connection to Skinner/behaviorism. Peikoff’s claim that modern behaviorism is “philosophically identical to Democritus” is overstated. Skinner’s radical behaviorism is methodologically motivated (study what’s observable) rather than ontologically motivated (deny mind exists). The philosophical problems overlap but the motivations differ. Still, the structural parallel — explaining behavior without reference to mental states — is real.
On atomism as physics: Spectacularly vindicated in broad outline. Matter is composed of discrete units; most observable properties emerge from underlying quantitative structure; mechanical laws govern inanimate nature. Democritus’s specific atoms are wrong (real atoms are divisible, complex, and governed by quantum mechanics rather than classical mechanics), but the impulse — reduce apparent diversity to combinations of simpler units — is the engine of all physical science.
On atomism as metaphysics (mechanistic materialism): Still contested but increasingly under pressure. The hard problem of consciousness remains unsolved. No materialist theory has explained why certain physical processes give rise to subjective experience. The self-refutation argument has never been answered to most philosophers’ satisfaction. Consciousness as a “cognitive primary” (the Objectivist position) or as requiring new physics (Penrose, integrated information theory) remain live alternatives.
On the quality/quantity distinction: The most consequential legacy. Modern science does describe reality in mathematical/quantitative terms, and does treat qualities (color, sound) as subjective experiences caused by quantitative features (wavelength, frequency). But whether this means qualities are “unreal” or just differently real is still debated. Qualia remain the hardest problem in philosophy of mind. Democritus opened a wound that hasn’t healed.
On determinism: Decisively refuted at the quantum level (Bell’s theorem, quantum randomness), though determinism persists in classical approximations. Whether human behavior is determined remains the subject of the free will debate, which is very much alive. The atomists’ specific mechanism (billiard-ball causation all the way up) is dead, but the question they raised — does physics leave room for genuine choice? — is not.