 The determinable X a given indexical experience belongs to, with respect to certain other experiences, helps us answer the question of what determines the reference of that experience, if not its ideal meaning species alone. In order to take the role played by the determinable X into account properly, we have to employ a Husserlian research strategy that could be called the dynamic method. That is to say, we have to look upon intentional acts as momentary components of certain transtemporal cognitive structures—dynamic intentional structures—in which one and the same object or state of affairs is represented throughout a period of time during which the subject’s cognitive perspective upon that object or state of affairs is constantly changing (see, e.g., Ideas, sec. 86). (Typical examples of dynamic intentional structures include continuous observations—which represent Husserl’s standard example—as well as those totalities of successive judgements, or momentary belief-states, that actualize one and the same continuous belief. For instance, my judgement that yesterday was Thursday actualizes the same belief as the judgement I could have given voice to yesterday by “Today is Thursday”.) Consequently, the determinable X is apt to lead us back through time towards the original situation where the reference of the relevant unified series of successive intentional horizons was fixed, like for instance the occasion of the subject’s first perceptual encounter with a particular object: the corresponding perceptual experience will belong to the same determinable X as all of the (remaining) experiences belonging to the relevant series. In a more recent terminology, one may say that in this perceptual situation the subject has opened a mental file about a particular object (cf. Perry 1980).