Absolutely.

I would cite to the wisdom of Socrates, in claiming to know nothing. "[W]hereas I, as I do not know anything, so I do not fancy I do. In this trifling particular, then, I appear to be wiser than he, because I do not fancy I know what I do not know."

And as far as the original question, Yes. Not sure if i can say ghosts are real or not, but I believe there are things that science as we consider it, cannot explain.