He was the first person to (formally) propose the idea of an ice age, and find evidence for it. That's pretty impressive. I don't see how what you pointed out a

He was the first person to (formally) propose the idea of an ice age, and find evidence for it. That's pretty impressive. I don't see how what you pointed out about his beliefs detracts from the point the author was trying to make by using him as an example of a driven individual. Does the fact Newton spent many years practicing alchemy detract from his achievements? It's not about whether or not they were right or wrong in hindsight.