Can Knowledge Be Harmful

There have been many times in my life when I have heard people use idiomatic expressions such as "some things are better left unsaid" and "what you don't know can't hurt you." I had never thought too much about these statements before, merely assuming them to be random expressions with no debatable meaning. However, several days ago I was talking with one of my friends about dating and she said "the knowledge that he's going out with her is painful enough." This got me thinking. Is it knowledge itself that is harmful and that we should not seek/know, or is knowledge impartial and it is the person that is harmful or construes the knowledge as harmful? In order to answer this question, I first asked myself: what is knowledge? While the question is remarkably broad, I simply took a simple definition and considered it: knowledge is a body of truths or facts gained over time through experience and the understanding of concepts and ideas. With this in mind, I then contemplated: is knowledge harmful? In my opinion, no knowledge is inherently evil or with harmful intent. In fact, I believe that knowledge is neither good nor evil, but simply impartial with no will of its own. I believe it is the people that interpret knowledge that put a negative or positive spin on it. Hitler's autobiographical-political book, Mein Kampf, is banned in some bookstores and libraries because some fear people will become influenced by it and adopt Hitler's ideology. If someone were to begin trying to exterminate Jews, it would be because of their malicious intent, not because of the knowledge the book itself contained. In a different example, biological science studies were intended to benefit mankind, by researching bacteria and viruses so that cures and medical vaccines could be created to help the sick. However, the same biological studies were used to create weapons for the purpose of biological warfare, intended to infect many victims with deadly diseases. Does this mean that the