A verb phrase 'phi' has the property of performativity if a person can, in the right circumstances, 'phi' just by uttering the sentence 'I phi' or 'I hereby phi'. Verb phrases like: 'promise to be there', 'congratulate you on your promotion' have this property, 'berate you', 'amuse you with a quip', 'describe the scene' don't have this property. G. considers the question what it is that the performative ones have that the others lack. How is it that they can be performative whereas the others cannot?