Osprey
10-09-2012, 03:30 AM
1. Liar Paradox (Epimenides Paradox)
This is a well known paradox written by the great stoical logician Chrysippos. The poet, grammarian and critic Philetus of Cos was said to have died of exhaustion attempting to resolve it.
A Cretan sails to Greece and says to some Greek men who are standing upon the shore: "All Cretans are liars." Did he speak the truth, or did he lie?
A week later, the Cretan sailed to Greece again and said: "All Cretans are liars and all I say is the truth." Although the Greeks on the shore weren't aware of what he had said the first time, they were truly puzzled.
If someone says "I always lie", are they telling the truth? Or are they lying?
2. Double Liar Paradox (Jourdain's paradox)
This version of a famous paradox was presented by English mathematician P. E. B. Jourdain in 1913.
The following is written on opposite sides of a card:
Back side:
THE SENTENCE ON THE OTHER SIDE OF THIS CARD IS TRUE.
Face side:
THE SENTENCE ON THE OTHER SIDE OF THIS CARD IS FALSE.
3. Barber Paradox (Russell's Paradox)
Analogue paradox to the 'liar paradox' formulated by English logician, philosopher and mathematician Bertrand Russell.
In a village, the barber shaves everyone who does not shave himself/herself, but no one else.
Who shaves the barber?
4. Lazy-bones Paradox
If destiny designed a master plan which defines everything that is to happen, isn't it useless, for example, to go to a doctor? If I am ill and it is my destiny to regain health, then I will regain health whether I visit a doctor or not. If it is my destiny to not regain my health, then seeing a doctor can't help me.
How could you question the presented opinion?
Discuss this paradox
Sophisms
1. Crocodile Sophism
A slim crocodile living in the Nile took a child. His mother begged to have him back. The crocodile could not only talk, but was also a great sophist and stated, "If you guess correctly what I will do with him, I will return him. However, if you don't predict his fate correctly, I'll eat him."
What statement should the mother make to save her child?
2. Is it possible to give what we don't have?
Sophist: "Yes, greedy man gives his cash with sorrow. However, he doesn't have the cash with sorrow, so he gives what he doesn't have."
3. What is better - eternal bliss or a simple bread?
What is better than eternal bliss? Nothing. But a slice of bread is better than nothing. So a slice of bread is better than eternal bliss.
This is a well known paradox written by the great stoical logician Chrysippos. The poet, grammarian and critic Philetus of Cos was said to have died of exhaustion attempting to resolve it.
A Cretan sails to Greece and says to some Greek men who are standing upon the shore: "All Cretans are liars." Did he speak the truth, or did he lie?
A week later, the Cretan sailed to Greece again and said: "All Cretans are liars and all I say is the truth." Although the Greeks on the shore weren't aware of what he had said the first time, they were truly puzzled.
If someone says "I always lie", are they telling the truth? Or are they lying?
2. Double Liar Paradox (Jourdain's paradox)
This version of a famous paradox was presented by English mathematician P. E. B. Jourdain in 1913.
The following is written on opposite sides of a card:
Back side:
THE SENTENCE ON THE OTHER SIDE OF THIS CARD IS TRUE.
Face side:
THE SENTENCE ON THE OTHER SIDE OF THIS CARD IS FALSE.
3. Barber Paradox (Russell's Paradox)
Analogue paradox to the 'liar paradox' formulated by English logician, philosopher and mathematician Bertrand Russell.
In a village, the barber shaves everyone who does not shave himself/herself, but no one else.
Who shaves the barber?
4. Lazy-bones Paradox
If destiny designed a master plan which defines everything that is to happen, isn't it useless, for example, to go to a doctor? If I am ill and it is my destiny to regain health, then I will regain health whether I visit a doctor or not. If it is my destiny to not regain my health, then seeing a doctor can't help me.
How could you question the presented opinion?
Discuss this paradox
Sophisms
1. Crocodile Sophism
A slim crocodile living in the Nile took a child. His mother begged to have him back. The crocodile could not only talk, but was also a great sophist and stated, "If you guess correctly what I will do with him, I will return him. However, if you don't predict his fate correctly, I'll eat him."
What statement should the mother make to save her child?
2. Is it possible to give what we don't have?
Sophist: "Yes, greedy man gives his cash with sorrow. However, he doesn't have the cash with sorrow, so he gives what he doesn't have."
3. What is better - eternal bliss or a simple bread?
What is better than eternal bliss? Nothing. But a slice of bread is better than nothing. So a slice of bread is better than eternal bliss.