Reactions to On the Origin of Species man to be envious of a naturalist like myself, immeasurably his inferior!" Darwin's had estimated that erosion of the Weald would take 300 million years, but in the second edition of "On the Origin of Species" published on 7 January 1860 he accepted that it would be safer to allow 150 million to 200 million years. Geologists knew the earth was ancient, but had felt unable to put realistic figures on the duration of past geological changes. Darwin's book provided a new impetus to quantifying geological time. His most prominent critic, John Phillips, had investigated how temperatures increased with depth
On the Origin of Species sentence [Light will be thrown on the origin of man and his history] I show that I believe man is in same predicament with other animals. Many modern writers have seen this sentence as Darwin’s only reference to humans in the book; Janet Browne describes it as his only discussion there of human origins, while noting that the book makes other references to humanity. Some other statements in the book are quietly effective at pointing out the implication that humans are simply another species, evolving through the same processes and principles affecting other organisms. For example, in Chapter III: "Struggle