They have a half-baked opinion on everything.

You have met them, haven't you?.  The autodidacts, the half-educated, spouting their banalities and most of the time with a quite terrifying confidence. They have a half-baked opinion on everything and all issued with an overriding certainty sans the humility of doubt.  You listen to them, secretly wishing there was some kind of restraining order in the ether, something to at least make them pause. If you want some comfort from this half baked onslaught read:  Bouvard and Pécuchet, Flaubert’s satire on the indiscriminate accumulation of half-digested knowledge.