A copy, qua copy, can never be the equal of the exemplar, and it may be much its inferior.
The commissioners feared that, so long as Greek was a sine qua non at the universities, these schools would be cut off from direct connexion with the universities, while the universities would in some degree lose their control over a portion of the higher culture of the nation.
The possession of the doctorate is a sine qua non for eligibility to a university chair, and to a lectureship in the university of Paris.
There is an obvious development from the serpent qua reptile to the deity or the devil, and that the original theriomorphic form is not at once forgotten can be seen in Zeus Meilichios, Aesculapius Amynos, in the Cretan snake-goddesses, or in the Buddhist topes illustrated by Fergusson.
The improvement of the telescope was justly regarded as a sine qua non for the advancement of astronomical knowledge.