 As we have seen, modal interpretations intend to provide, for every instant, a set of definite-valued properties and their probabilities. Some advocates of modal interpretations are willing to leave the matter at that. Others take it to be crucial that also questions of the following form are answered: given that the property \(P\) of a system has the actual value \(\alpha\) at time \(t_0\), what is the probability that its property \(P'\) has the actual value \(\beta\) at time \(t_1 \gt t_0\)? In other words, they want a dynamics of actual properties.