Taken from here
3. The Idols of the Market Place. These are hindrances to clear thinking that arise, Bacon says, from the �intercourse and association of men with each other.� The main culprit here is language, though not just common speech, but also (and perhaps particularly) the special discourses, vocabularies, and jargons of various academic communities and disciplines. He points out that �the idols imposed by words on the understanding are of two kinds�: �they are either names of things that do not exist� (e.g., the crystalline spheres of Aristotelian cosmology) or faulty, vague, or misleading names for things that do exist (according to Bacon, abstract qualities and value terms � e.g., �moist,� �useful,� etc. � can be a particular source of confusion).