何時用上 necessary evil ?

唔明點解你的老師會說 a necessary evil 比較少見。

學術界好多政治學者提起必然罪惡(necessary evil)都會加a

例如:
Suvi Soininen ：From a Necessary Evil to an Art of Contingency: Michael Oakeshott：Conception of Political Activity ﹑

J. Craig Barker ：The abuse of diplomatic privileges and immunities:a necessary evil?

John P. Kaminski ：A Necessary Evil?: Slavery and the Debate Over the Constitution


而 Glenn Tinder(外國政治學系教授) 在In Defense of Pure Tolerance中，提到忍受(tolerance)是必然之惡，亦有加a:

Though tolerance arose as a necessary evil, not an intrinsically good
system,

Tolerance arose in large part because it seemed to be the
only alternative to endless religious wars; it was a necessary evil.


全文:http://www.jstor.org/discover/10.2307/3234026?uid=3738176&uid=2129&uid=2&uid=70&uid=4&sid=21101697135597

而在一般學術論文中, necessary evil亦多有a,如收錄在Geographical Journal的"Good, bad or ‘necessary evil’? Reinterpreting the colonial burning experiments in the savanna landscapes of West Africa" :

Late fire is actively discouraged and often illegal; and early fire is
acceptable as a ‘necessary evil’, but only under specific, controlled circumstances.
原文:http://faculty.fortlewis.edu/KORB_J/global%20fire/west%20africa%20and%20burning.pdf


所以用a necessary evil / as a necessary evil/ is a necessary evil 係好普遍的做法。

2013-01-25 01:36:09 補充：
相關補充，請見http://hk.knowledge.yahoo.com/question/article?qid=6913012500015&mode=w