请问在描述前人著作或者观点时应该用一般现在时还是一般过去时？

在How to Get the Poor off Our Conscience中，作者对于两个前人的观点采用了不同的时态。

过去时 In the 1830s a new formula became available for getting the poor off the public conscience. The essentials are familiar: The poverty of the poor was the fault of the poor. 

一般现在时 That phrase--"survival of the fittest"--came, in fact, not from Charles Darwin but from Spencer, and expressed his view of economic life. The elimination of the poor is nature's way of improving the race.