Ignorance is the prime base from which intolerance grows. The best short and concise sentence that I've read to support such a statement is provided by Michael Levine in "Lessons at the Halfway Point":

"If you don't personally get to know people from other racial, religious or cultural groups, it’s very easy to believe ugly things about them and make them frightening in your mind." Reader's Digest (Canada Edition) November 1996, P. 48-9.

To provide an example of how ignorance motivates a person to be intolerant I'll use an incident that happened to me in the 1960s. Because it indicates that the perpetuator had a deep belief in the demonized picture of First Nations Peoples, invented over the ages with malicious intent by Caucasian propagandists, one cannot come to any conclusion other than that it was a direct result of ignorance of First Nations cultures and white supremacist thinking. It was among the most racially demeaning experiences I've ever encountered, and, related to my racial origins and human rights activities, I've encountered tons of them.

In the late 1960s I was hired as assistant paymaster by the paymaster of a construction company. Over the course of the first week or so, from various locations around the office, I often caught her studying me out of the corner of her eye.

In due course, I was called into her office for a chat. This is how she began: "You’re an Indian, aren't you?" I responded: "Yes." She followed with this: "If I had known it when you applied I wouldn't have interviewed and hired you. However, you're here, and seem to know what your doing and competent. Seeing that no one else seems to have caught on that you’re an Indian and objected to you being here I'll agree not to tell anyone and, providing you agree to keep it to yourself, I'll keep you on until such time as someone does make a fuss about it."