# The Liar (a logic song)

### My new logic music video is out! A collaboration with the supremely talented Hannah Hoffman. The laughing Liar lights logic's law afire, laughing as the world burns. Meow.

The Liar paradox is a conundrum about the nature of truth arising when a person, the Liar, announces “I am lying.” Is the Liar's pronouncement true or false? If the Liar speaks truly, then truly he is lying; but if he is lying, then he spoke truly. Either case thus leads to contradiction. And so the laughing Liar lights logic's law afire, laughing while the world burns.

According to Tarski's disquotational theory of truth, a sentence is true when the proposition it asserts is the case. Thus, “snow is white” is true if and only if snow is white—truth merely removes the quotation marks. The Liar challenges this deflationary theory for a self-applicable truth predicate, one applying to assertions using that predicate, as in the Liar. The Visser-Yablo paradox aims to avoid self-reference with an infinite list, each statement asserting the falsity of all subsequent statements. If any is true, then all the following are false, and so they should be true; and so none are true, which means that all must be true. Crazytown!

Music and video by Hannah Hoffman; lyrics by Joel David Hamkins. Read more about the Liar paradox in my essay Infinite Liars.

## Lyrics

A merry prankster is the Liar, Lighting logic's law afire. Reason's ruin, chaos eyeing, With three words only: I am lying. The liar's sentence, “I am lying” Has neither True nor False applying, For if he's truthful, then he lies, But if lying, then Truth flies. Either case is contradiction, Truth here has no jurisdiction. I am lying, Falsifying, Self denying, Truth untying! The laughing Liar's paradox Unlocks a logic tinderbox. Liar's fire climbing higher, Havoc stocks and Truth defrocks. For if he lies, logic dies, And if true, untruth is due. There's no avoiding contradiction, Truth enjoys no benediction. He is lying, Falsifying, Self denying, Truth untying! If he's truthful, Liar lies, But if lying, reason cries. The proof is clear, in contradiction; Truth's arrears, in dereliction! Tarski's Truth is disquotational, His Truth scheme truly inspirational. He says that “snow is white” is true, In case the powder's bright for you... A self-applying predicate, For Truth is truly delicate. I am lying, Self decrying, Reason trying, Logic frying! What a jokester, whimsy's sire, Laughing Liar's dumpster fire. Reason ruined, in a mire, Truth thus tried by Liar's ire. A solemn choir sings at the pyre, A funeral for Truth expired. All logic, reason, lit afire, Thanks to prankster laughing Liar. A cue to Visser-Yablo's due; Review their endless Liars queue. Each softly coos a clue anew: “No sentence subsequent is true...” “No sentence subsequent is true...” “No sentence subsequent is true...”

#### Bonus choral verses:

He is lying! uncomplying! disqualifying! Are you buying?! He is lying stupefying trouble-spying Fools are flying! I am lying self belying ill supplying Truth defying I am lying self decrying reason trying logic frying I am lying misapplying mystifying mortifying He is lying crucifying Truth is crying truly dying!