Welcome to Episode 346 of Lucretius Today. This is a podcast dedicated to the poet Lucretius, who wrote "On The Nature of Things," the most complete presentation of Epicurean philosophy left to us from the ancient world. Each week we walk you through the Epicurean texts, and we discuss how Epicurean philosophy can apply to you today. If you find the Epicurean worldview attractive, we invite you to join us in the study of Epicurus at EpicureanFriends.com, where we discuss this and all of our podcast episodes.
This week we are continuing our series reviewing Cicero's "Academic Questions" from an Epicurean perspective, which gives us an overview of the issues that split Plato's Academy and helps us understand Epicurus' position on the same issues. This week will continue in Section 13 of Book Two.
Our text will come from
Cicero - Academic Questions - Yonge We'll likely stick with Yonge primarily, but we'll also refer to the Rackham translation here: Cicero On Nature Of Gods Academica Loeb Rackham : Free Download, Borrow, and Streaming : Internet Archive
As we proceed through the end of Academic Questions these are the topics we expect to cover:
24. Lucullus's Extended Rebuttal of the Academic Doctrine, and His Concluding Appeal to Cicero (2:XIII)
25. Cicero Begins His Reply (2:XX)
26. Cicero Lays Out the Syllogism About Assent and Opinion (2:XXI)
27. Cicero Turns to Antiochus's Own Inconsistency (2:XXII)
28. Cicero Defends His Citation of the Ancient Philosophers (2:XXIII)
29. Cicero Adds Chrysippus and the Cyrenaics, Then Returns to Arcesilas and Zeno (2:XXIV)
30. Cicero Returns to Attacking the Senses (2:XXV)
31. Cicero Presses the Sun's Size and the Limits of Trained Perception (2:XXVI)
32. Cicero Turns the "Art" Argument Back on Lucullus (2:XXVII)
33. Cicero Multiplies Examples From Madness (2:XXVIII)
34. Cicero Attacks Reason and Dialectics: The Sorites Paradox (2:XXIX)
35. Cicero Presses the Liar Paradox (2:XXX)
36. Cicero Presents Carneades's Own Positive Doctrine of Probability (2:XXXI)
37. Cicero Distinguishes the Academic Position From Epicurus's (2:XXXII)
38. Cicero Defends Probability Against the Charge That It Cannot Support Memory or Action (2:XXXIII)
39. Cicero Answers the "Self-Refuting" and "Two Incompatible Propositions" Objections (2:XXXIV)
40. Cicero Broadens the Argument Beyond the Stoics (2:XXXV)
41. Cicero Reflects on His Own Position Among the Competing Schools (2:XXXVI)
42. Cicero's Survey of Disagreement Among the Natural Philosophers (2:XXXVII)
43. Cicero Presses the Problem of Providence and the Limits of Physics (2:XXXVIII)
44. Cicero's Survey Continues: The Soul, the Antipodes, and the Motion of the Earth (2:XXXIX)
45. Cicero Asks Which Natural Philosopher He Would Even Choose to Follow (2:XL)
46. Cicero Turns to Ethics: Even the Gods Are Disputed (2:XLI)
47. Cicero's Roll Call of Rival Schools on the Chief Good, Part One (2:XLII)
48. Cicero's Roll Call of Rival Schools on the Chief Good, Part Two (2:XLIII)
49. Cicero Weighs Zeno Against Antiochus on Virtue and the Happy Life (2:XLIV)
50. Cicero Catalogs the Stoic Paradoxes About the Wise Man (2:XLV)
51. Cicero's Climactic Debate Between Pleasure and Honor (2:XLVI)
52. Cicero Turns to the Canon of Truth, and Zeno's Hand (2:XLVII)
53. The Dialogue's Close (2:XLVIII)
Complete transcript is here:
In today's episode since we are continuing to talk about about the Stoics unwillingness to defend ALL sensations as true, I want us to remember to include:
Cicero, Academica ("Academic Questions"), Book II ("Lucullus"), Chapter XXV (C.D. Yonge's 1853 translation)
"Therefore you have always one backer who will plead the cause at his own risk: for Epicurus brings the matter down to this point, that if once in a man's life one of his senses has decided wrongly, none of them is ever to be trusted."
and
Cicero, Academica II, Chapter XXVI:
"There are four principles which conduct you to the conclusion that there is nothing which can be known, or perceived, or comprehended; -- and it is about this that the whole dispute is. The first principle is, that some perceptions are false; the second, that such cannot be perceived; the third, that of perceptions between which there is no difference, it is not possible that some of them can be perceived and that others cannot; the fourth, that there is no true perception proceeding from the senses, to which there is not some other perception opposed which in no respect differs from it, and which cannot be perceived. Now of these four principles, the second and third are admitted by every one. **Epicurus does not admit the first**, but you, with whom we are now arguing, admit that one too, -- the whole contest is about the fourth."
- Some perceptions are false.
- A false perception cannot be "perceived" (i.e. cannot count as genuine knowledge) -- this follows once (1) is granted.
- Where two perceptions are indistinguishable from each other, it cannot be that one is knowable and the other is not -- i.e. if a false perception is indistinguishable from a true one, you can't selectively "know" the true one and not the false one.
- Every true sense-perception has some corresponding false perception exactly like it, indistinguishable from it -- so no sense-perception is ever safe from principle 3's contamination.
Cicero's own accounting of where each school stands:
- Principles 2 and 3 -- accepted by everyone in the debate (Epicureans, Stoics, Academics alike).
- Principle 1 -- rejected by Epicurus alone. If no perception is ever false, principles 2-4 never get to operate on anything, and the skeptical conclusion has no foothold.
- Principle 4 -- accepted by the Stoics (Lucullus, in this dialogue), which is why Cicero says "the whole contest is about the fourth": the Stoics already conceded (1), so their only remaining line of defense against skepticism is denying (4).
Cassius August 14, 2026 at 8:44 AM
Lucretius Today Podcast Episode 346 is now available: "Epicurean Defense of The Senses Against Plato's Cave Analogy" -
Complete transcript is here:
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