Do you believe that the light bulb went off in [Darwin's] head during the voyage of the Beagle?Seems to me we could do with another HMS Beagle to inspire young scientists, and give them a lifetime supply of data with which to work.
You know, I do think that. I think that historians have perhaps swung too far the other way for many years, and believed that it only happens after the voyage. But if we go back and we look at those notebooks, the field remarks that he writes down, his observations in his private diaries, it seems that he was becoming unsettled by the idea of "species".
We see in his notes an intelligent young person thinking through the consequences of what he was reading and what he was discovering, and beginning to formulate big questions. Yes, those big questions only really become answerable when he returns, when what had seemed like simple varieties became species, and he wonders: what kind of creator does such a thing? It was certainly a long process, but what we forget is that the Beagle voyage provided Darwin with a lifetime supply of data to pursue.
In fact, his first publications were in geology, he was a wonderful geologist, and had been places where very few geologists had traveled. We forget that he was also a zoologist, he loved botany, and so he was a very skillful, complete naturalist. Those of us who only read The Origin of Species tend to forget the other aspects of his life. And it’s the voyage of the Beagle that supplies him with that information.
[h/t Adrian Thysse]