Still one of my favourite quotes (free image)
I.e.: Keep your mind open. Don't be narrow. Look around. Nature is bigger than what you believe, and may not fit into your confining interpretations of it.
It's a quote from 'Hamlet', where Horatio and Hamlet are finally confronted by the evidence of the visible ghost of Hamlet's father.
'This is, in fact, the essence of skepticism. Skeptics aren't people who disbelieve because they don't want to believe. Skeptics disbelieve because they haven't been presented with evidence. I don't believe in ghosts because I've never seen a ghost, and I don't know any reliable observer who has. Those who do report seeing them are unreliable, and generally not skeptical: they see what they want and not what they don't want, and don't pry any further into things.'