In a very interesting contribution to this Conference, Prof. von Weizsäcker and Dr. Görnitz[4] have argued that to the extent that the Copenhagen interpretation, the transactional interpretation, and other interpretations are both self-consistent and also consistent with the quantum mechanics formalism, one can deduce a ``dictionary'' or set of interpretational transformations which can render one interpretation in the terms or ``language'' of another. This demonstrates a kind of equivalence principle for interpretations. I believe that their argument is correct and that there is this sort of relationship between the transactional and Copenhagen interpretations. The formalism itself clearly provides one such link between one interpretation and another, so it should not be a surprise that such a transformation or remapping can be made.
One should proceed carefully, however, in reading too much significance into this result. In particular, the transformation procedure described is quite capable of mapping the effects in one interpretation into causes in the other, and vice versa, thereby reversing a causal relationships. For example, suppose that we carefully measure as a function of time the coordinates of a child on a swing and the coordinates of the moon moving in its orbit. It is then possible to characterize the motions of the moon in terms of the position of the child. This ``mapping'', however, places the child in an inappropriate position of central importance, for it gives the impression that the child's motion is somehow the cause of the moon's motion.
It is my view that the Copenhagen interpretation of quantum mechanics makes just this kind of causal error in attributing to collapse of the state vector to a change in the knowledge of an observer. Certainly the observer's change in knowledge is in good sequential correspondence with the collapse of the state vector, but this does not establish that the one is the cause of the other. Like the child in the swing, the Copenhagen interpretation places the observer in an inappropriately central position. The Copenhagen interpretation is observer-centric in the same sense that Ptolemaic astronomy is geo-centric. That one can map the epicycles of Ptolemy into the orbits of Copernicus does not demonstrate that the two theories are interchangeable.