The tendency of people to make assumptions about things they know nothing about is fed by arrogance as much as (or even more than) mere ignorance. A good example is the scientist and controversialist Richard Dawkins's book The God Delusion, which uses his expertise in evolutionary biology to speculate on the evolutionary value of religion in the past and to attest to its complete lack of value today.

The problem with this approach is that Dawkins is ignorant of bodies of knowledge - such as the sociology of religion and critical theology - that have approached religion in very different ways. This ignorance does not disqualify him from writing a book on religion, but what is inexcusable is his apparent ignorance that these bodies of knowledge even exist. His arrogance leads him into making sweeping statements about religion that are over-reliant on his own narrow field of expertise, bolstered with his own prejudices.