Original sentence: While such notions of unidirectional "progress" are not really supported by ideas of evolution, the 1859 publication of Darwin's Origin of Species gave his work more popular acclaim, as did the fact that his work served to justify many of the political causes of the day, especially British imperialism
Edited sentence: While such notions of unidirectional "progress" are not really supported by ideas of evolution, the 1859 publication of Darwin's Origin of Species gave his work more popular acclaim, as did the fact that his work served to justify many of the hard-to-justify political causes of the day, especially British imperialism