Science cannot progress without reliable and accurate measurement of what it is you are trying to study. The key is measurement, simple as that.

Language and words for psychopaths are only word deep; there is no emotional colouring behind it. A psychopath can use a word like, 'I love you' but it means nothing more to him than if he said, 'I'll have a cup of coffee.'

Psychopaths view any social exchange as a 'feeding opportunity,' a contest or a test of wills in which there can be only one winner. Their motives are to manipulate and take, ruthlessly and without remorse.

Robert D. Hare Quotes