Paradox
A paradox was an apparently self-contradictory thought or situation.

In 2258 of the alternate reality, Spock Prime implied that universe-ending paradoxes would occur if  broke his promise not to tell younger  about him. The latter was surprised that the former had lied. Spock Prime's real reason for making Kirk promise this was to allow their friendship to happen in this reality too. ()

Paradoxes can be used to induce self-destruction in certain self-aware machines. The invasive program designed by Data and Geordi La Forge in 2368 featured a paradoxical geometric figure. ()

According to the Species 8472 individual representing Valerie Archer, Human beings are quite a paradox. ()

In 2377, when asked by Tom Paris to provide parenting hints, Tuvok offered, " Offspring can be disturbingly illogical, yet profoundly fulfilling. You should anticipate paradox." ()

List of paradoxes 
 Chicken and the egg
 Causality paradox
 Cycle of causality
 Dali paradox
 Déjà vu
 Felker Paradox
 Flux paradox
 Pogo paradox
 Predestination paradox
 Temporal paradox

External link 
 

fr:Paradoxe
Philosophy