What is the freedom of thought quote that refers to a man drowning in a sea of his own ideas?

I'm trying to remember a quote I once heard pertaining to freedom of thought/speech. It poetically described one's refusal to listen to differing opinion as to drown in a sea of one's own ideas... or something to that extent. I seem to want to say it was a quote of a greek philosopher maybe? It has been some time since I last heard the quote and haven't yet found it online through constant searches.