How we change what others think, feel, believe and do
A paradox is a statement (or set of statements) where a seemingly impossible contradiction is presented.
I always lie. (If the person is a liar, then this is true, which makes them not a liar).
Death shall be no more; Death, thou shalt die. (how can death die?)
Youth is wasted on the young. (but how can young people know the value of youth without not having it?)
Paradoxes may be self-referential, contradictory and circular. They may also use half-truths or falsehood, although the listener may be initially distracted from this fallacy by the confusion of the paradox.
Paradoxes can be used as explanations, such as the circular paradox known as the 'grandfather paradox' which is used to discount the possibility of time travel. In this conundrum, a person travels back in time and kills their grandfather before he has children, so preventing the person being born (and also from killing the grandfather).
Paradoxes can appear to be false but actually be true, such as a person having their fifth birthday after living twenty years (if they are born on February 29th in a leap year).
Paradoxes may be deliberate puzzles and are common in philosophy, where pedants spend time musing upon their construction and how feasible solutions may be derived. Poets likewise delight in the twists of a paradox and seek to place them in matching linguistic settings. Authors also use paradoxes to create excitement, confusion and enlightening lessons.
An antinomy is a false paradox that is arrived at by using accepted forms of reasoning. A dialetheia is a paradox that is both true and false at the same time, such as when you say 'I am both in the room and outside the room', whilst you are standing in the doorway.
A moral paradox occurs where values conflict, for example where a person is faced with the choice of killing another person or letting a loved one die.