The opposite of thinking clearly is being muddled. To be conscious of being muddled is a horrible experience. To avoid it we may even be tempted to shut our minds and swallow a belief, ready-made, from some expert authority.
Susan StebbingA system is said to be coherent if every fact in the system is related every other fact in the system by relations that are not merely conjunctive. A deductive system affords a good example of a coherent system.
Susan Stebbing