 The Cooperative Principle further assumes that the participants in every conversation strive only to achieve common goals. From the perspective of social psychology, evolutionary biology, and game theory, Pinker (2007) observes that pure cooperation is generally an unrealistic idealization or naive assumption. Conversations are often among adversaries, whose goals beyond communication are opposed. It would be foolhardy and possibly dangerous for an interrogator to presume that a prisoner of war or terrorism suspect is being cooperative. Even when participants are friends or relatives, they often have some divergent goals, and may give priority to other principles  (§10).  To the extent that they diverge, the speaker’s goals may be promoted and the hearer’s goals thwarted by withholding information, providing misinformation, going off on a tangent, or being obscure. Even when it is correctly presumed that a speaker is not being cooperative, the speaker may use all the figures and modes of speech. If the prosecuting attorney asks the defendant whether he was in the bank on the day of the robbery, the defendant might answer “I took my mother to the hospital that day”, thereby implicating that he was not at the bank. He may do this in the hope of misleading the jury as well as the prosecutor. The official purpose of the conversation is to get at the truth, the whole truth, and nothing but the truth. But the defendant’s purpose is to hide it.