Knowledge in this world is a very special trait to have. If you replaced knowledge with ignorance you would make a fool out of yourself. Once knowledge is obtained great things will be accomplished.
As time progresses so does knowledge. Notice where the world is today, we have learned that there is more than just earth and how putting different things together creates something new. With knowledge, we all have the advancements that no one else before us has, and that gives us power over them.
Another great reason for having knowledge is that it helps us advance into the future.