0 a necessary condition without which something is not possible:
1 something that must be done or achieved before anything else is done or achieved:
Others see the ability of citizens to exercise basic political rights as the sine qua non of legitimation.
Friendship was viewed by many as the sine qua non of a quality relationship.
This reconstruction was an ideological sine qua non of the project of legibility.
Instead, the institutionalized tool has been presented as the sine qua non of scientific inference.
Judicial independence is thus a sine qua non for the judicialisation of policy.
It is, in a way, the sine qua non of municipal connections, since it gives them grandeur and legitimacy.
Candor about these aims is a sine qua non of any useful debate over the legitimacy of the methods used to advance them.
If paradox is truly the sine qua non of key aspects of performance, we must perforce engage with such textual convolutions via a paradoxology.