There is wisdom in not knowing, and it is a wise person who can say, "I don't know." For no one knows everything. There are many types of wisdom -- from intellectual to emotional to physical intelligence. Yet, even deemed experts in their fields do not know all there is to know about mathematics, yoga, literature, psychology, or art. It is a true master who professes ignorance, for only an empty vessel can be filled.
There are many things in life that we don't know, and there are many things we may have no interest in finding out. There is freedom in saying "I don't know." When we admit that we don't know something, we can then open ourselves up to the opportunity to learn. And there is power in that. We can't possibly know everything. And when we think we do, we limit ourselves from growing and learning more than what we already do know. A person who can admit to not knowing tends to be more intellectually and emotionally confident than someone who pretends to know everything. They also tend to be more comfortable with who they are and don't feel the need to bluff or cover up any perceived ignorance. People can actually end up appearing more foolish when they act as if they know something that they don't.
We would be wise to respect people who freely admit when they don't know something. They are being honest, with us and with themselves. And we, too, should feel no shame in saying, "I don't know." In doing so, we open ourselves up to the unknown. We can then discover what lies beyond our current levels of understanding. It is the wise person in life that answers questions with a question and inspires the pursuit of internal answers with a funny face, a shrug, and a comical, "I don't know."