What does "dare" mean here?

Question

I searched online dictionaries for the word dare but I don't understand the meaning of sentence below:

As he dared only to hope in that great book, light has been cast upon not just the worlds of plants and animals, but on ourselves and our origins.

Being together "dare" and "only" makes me puzzled. So, Could you please explain it to me?

The fuller text is here:

A century and a half after The Origin, Darwin can be seen to have been triumphantly right about almost everything. Evolution is now no more “just a theory” than is chemistry and, like all other sciences, it provides a logical way of looking at the world. As he dared only to hope in that great book, light has been cast upon not just the worlds of plants and animals, but on ourselves and our origins.

Darwinism makes sense of what was once no more than a jumble of unconnected facts, and in so doing unifies biology. Modern psychology, ecology and more find their birthplace in the pages of his greatest work. A century-and-a-half on, evolution is as central to our understanding of life as gravity is to the study of the universe.

Read more: https://www.newscientist.com/article/mg20427343-400-origin-of-species-revisited-recapitulation-and-conclusion/#ixzz67QsnuQIa

Answer 1

The use of "dare" here isn't anything especially fancy. It's the most common definition:

to be sufficiently courageous to

What's maybe confusing you is how "only" works. Only is modifying "to hope." By saying "dared only," the author means Darwin did not dare to do anything any more bold than merely hoping (to cast light upon plants, animals, ourselves and our origins).

Darwin's work on evolution has become so pivotal that it's now totally mainstream; regular people all over the world understand the theory. But at the time he published On the Origin of Species, this was new stuff. It would be plenty ambitious for Darwin even to hope his work would have the immense impact it ultimately ended up having. (Every scientist hopes to publish something that changes the world, but few actually do.) So he dared to hope for that, but he didn't say, make a written prediction that his work would change the world, or go to the news media and proclaim how big of a deal his research is.