Open-minded

What exactly does this mean? And further more, how can anyone be truly open-minded with all prejudices and instinctual tendencies that we have built in? Really ask yourself. How can you truly know yourself? Because in reality we learn new things about ourselves every day until we die. To think you truly know yourself is ignorance. It also gives you a feeling of superiority over others, allowing you to close yourself off, to protect yourself. You shouldn't have to protect yourself, you should be able to just let yourself be.