You all already know the answer to this question. I want to give you a particularly vivid example.
In eighteenth-century France, as in other places in Europe, Catholics massacred a lot of Protestants, and the reverse was often true as well. One of the worst massacres was in August, 1572, when French Catholic mobs murdered thousands of Protestant Huguenots in the St. Bartholomew’s Massacre. Historical summaries generally say the triggering event of the massacre was the attempted assassination of the Admiral de Coligny. But there was more to the story. I cannot find this information online, but I distinctly remember reading in a book in 1976 (written by Henri Noguères) that one of the triggering events was the flowering of a crabapple tree. Crabapple trees usually bloom in spring. When some of them bloomed in late summer in Paris, many people, already stirred up by religious zeal, took this to be a miracle; if a miracle, then a message; if a message, then from God; if from God, it meant that they were supposed to go kill Huguenots.
This event, however, was all based on ignorance—in this case, botanical ignorance. If crabapple (or Bradford pear) trees experience a summer drought, and then rain begins to fall, the rain serves as a trigger that makes the trees bloom. This is because the trees do not have heat and cold sensors; to a tree, winter is dry (because the water is frozen) and spring is wet. Therefore, many trees will respond to a dry midsummer followed by a wet late summer as being winter followed by spring. This is why the crabapple trees bloomed in Paris in August 1572.
When the trees bloomed, the religious zealots did not know why. And if they do not know why, then it must be a miracle. This was their religiously deluded line of reasoning. Who knows how many people lost their lives because some religious zealots did not know enough botany!
This is my six hundredth post.