"He used also to say that when he saw physicians, philosophers and pilots at their work, he deemed man the most intelligent of all animals ; but when again he saw interpreters of dreams and diviners and those who attended to them, or those who were puffed up with conceit of wealth, he thought no animal more silly."

The life of Diogenes in Lives of Eminent Philosophers by Diogenes Laertius*, http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%...