...what you don't know. Realizing this gives us an insight that's very instructive. Watch the following link.
If you have read the sectioned entitled God, you have a fair idea of how I view science and religion. And this isn't a jab at science (I could as easily direct you to Isaiah 45:7; KJV). It is simply further evidence that nobody knows all there is to know. That being the case, it seems obvious to me that we could benefit from a more inquisitive attitude towards these two disciplines. Less dogmatic and more flexible. I would further suggest that we could apply the same attitude toward our relationships (and improve them dramatically!) Being "right" seems to have an inordinate power to separate rather than resolve.
To answer, "I'm not sure" or "I don't know" isn't an acknowledgement of a defective intellect. Quite the contrary. Knowing what you don't know is powerful testimony to the accuracy of what you do know.