aporia

Concise Oxford English Dictionary © 2008 Oxford University Press:
aporia /əˈpɔːrɪə, əˈpɒrɪə/

▶noun

• 1 an irresolvable internal contradiction or logical disjunction in a text, argument, or theory.

• 2 Rhetoric the expression of doubt.

– derivatives
aporetic adjective.

– origin C16: via late L. from Gk, from aporos ‘impassable’.