Accessibility is a dynamic discourse structure that is the sum of the salience structure of particular referential expressions. On the one hand, accessibility is continuously updated by referential expressions, while on the other, it determines the reference of definite expression. In this paper, it is shown that not only indefinite noun phrases, but also definite noun phrases update the accessibility structure of a discourse by promoting the actual referent to the most salient of its kind and some supersets. This dynamic potential of definite noun phrases establishes text coherence by means of salience spreading.