The examples were intended to demonstrate the point that saying "X is bad. Y is worse" is not an "endorsement of X".
The postings were widely criticised.
"If you want to make a point about logical fallacy, why use rape as an example? For survivors, this is not an academic game," wrote feminist writer Laurie Penny.
"I'm glad @RichardDawkins is here to tell us objectively & comparatively how bad our rapes were. Go away and learn compassion," wrote user @ThatSabineGirl.
Dawkins, author of bestseller "The God Delusion", retweeted messages of support from some of his near one-million followers in response to the outcry.
In a later blog, he described the incident as a "bizarre Twitter storm".
"I wasn't even saying it is RIGHT to rank one kind of rape as worse than another," Dawkins wrote.
"I was only talking logic, with no desire to make light of the seriousness of any kind of rape or any kind of pedophilia."
- Daily Mail