The word crisis stands for another cognate of aporia and paradox. It is related to a turning point that has to turn either one way or another. Alternatively, François Jullien talks about the Chinese approach to these undecidable turning points as bearing the freedom and potentiality of change, in a positive sense, compared to the Greek-European interpretation of a negative constraint to take action (cf. e.g. Jullien’s Silent Transformations and “crisis” an article by Jullien published in Le Monde, 2009).
The etymological definition of the English word crisis:
“Early 15c., from Latinized form of Greek krisis “turning point in a disease” (used as such by Hippocrates and Galen), literally “judgment, result of a trial, selection,” from krinein “to separate, decide, judge,” from Proto-Indo-European root *krei- “to sieve, discriminate, distinguish” (cognates: Greek krinesthai “to explain;” Old English hriddel “sieve;” Latin cribrum “sieve,” crimen “judgment, crime,” cernere (past participle cretus) “to sift, separate;” Old Irish criathar, Old Welsh cruitr “sieve;” Middle Irish crich “border, boundary”). Transferred non-medical sense is 1620s in English.” http://www.etymonline.com