I've used the phrase more than once, the term "willful ignorance." It bears more definition, and not as part of a greater idea or as supporting evidence for another concept.
People try to codify the world.
They try to organize it like some big library or the chambers of a mad scientist's laboratory. They take everything in the world, everything that they perceive or understand, and put it in a big box that they slap a label on, reading This is what IS. And anything that comes into their perception after they've made that box, after they've sealed it up and put it away? It's not just turned away like somebody without an invite to the gala.
It's met with more than just derision and scorn, it's met with hate. Pure, almost tangible hate, so intense in its heat that it wraps around to become utterly freezing. How dare the world attempt to be more than what they have codified it as?
This codification, this boxing away, is for more than just facts. Presumptions, generalizations, everything goes into the box. If any of these beliefs are challenged, the challenge is met with self-righteous fury and the fervor of a zealot.
The saddest thing is that such ignorance, such imposition of limits on the very universe itself, is not limited to just the uneducated. Scientists will reject theories simply because they don't meet with that scholar's interpretation of the universe; sociologists will deny that a community can act in a certain way because it doesn't gel with what they understand. Even conspiracy theorists and believers in aliens will reject better-argued theories because such things don't gel with their beliefs.
When our beliefs are challenged, it is natural, understandable and even right to want to defend them. But to confront such questioning with nothing but violence, hate and noise is to do a disservice to oneself and humanity as a whole. One must be willing to learn.
That the earth revolves around the sun due to gravity is a process that can be observed readily, and nowadays only the most radical protest otherwise. But at the time it was proposed, the theorists were threatened with death and dismemberment for daring to question the existing system of "facts," which have since been proven false.
Today, a disturbing number of people prefer to think of George Zimmerman as a man who defended himself against an attack by a thug, or think he was justified in killing someone who would have killed someone at some point in time. These same people believe that all evils in the world seem to be caused by acceptance of people and concepts that they would rather not acknowledge as fact.
I put it to the people of America, and the people of the world: the single greatest threat facing us is the willful ignorance of humanity at large: denial that toxins are poisonous, rejection of the potential of global climate change instead of taking care just in case we are killing the planet, and other such examples of completely backward thought can all draw their origins back to willful ignorance, rejection of information that does not fit one's limited perceptions of the universe.
Evil in itself is a powerful force, but willful ignorance allows for the propagation and festering of evil more than any other concept, and it is also the hardest to cure, as we can't force people to learn, nor can we control what people think without becoming monsters ourselves.