Question

As is well known, the Torah sees the fulfillment of predictions about the future spoken by a prophet as a criterion for confirming the authenticity of his mission in the word of God (Deuteronomy 18 and elsewhere). But what happens when a prophet offers predictions that can be interpreted in several ways? In such situations, after time passes, it can happen that the prophecy is interpreted retroactively in light of the events that occurred. Can the fulfillment of his predictions still be used as evidence for his mission?
 
On the one hand, it is clear to us that a “prophecy” that from the outset could bear any interpretation whatsoever—like the vague forecasts in the astrology column of the weekly newspaper, a prediction that any event in the world could retroactively be said to fulfill—really says nothing. On the other hand, there may be predictions that can indeed be interpreted in several ways, but whose level of detail is still high enough that the chance of fulfillment is extremely small. What is required, then, is that there be some relation between the number of reasonable interpretations that can retroactively be assigned to the prophecy and the likelihood of the events occurring from the perspective of the time it was published. If, for example, we say for the sake of argument that the number of possible interpretations of a certain prophetic text does not exceed 10, while the chance of the events that ended up occurring—and which were later found to match the prophecy—is one in ten million, then despite the certain ambiguity, this would still be excellent confirmation of the prophet’s mission (seemingly a probability of one in a million).
 
In other words, the lower the a priori probability that the events will occur, and the narrower the range of plausible interpretations, the stronger the confirmation. And vice versa.
 
What does the Rabbi think?