Measurements are essential ingredients of the quantum formalism. Quantum mechanics presupposes measurements and is vacuous without them. Needless to say, "measurements" are not synonymous with Bell's "piddling laboratory operations." Any event or state of affairs from which either the truth or the falsity of a proposition of the form "the observable O has the value V" can be inferred, qualifies as a measurement.

As we have seen, the probabilities that quantum mechanics permits us to calculate are not probabilities with which this or that property or value is possessed, regardless of measurements, but probabilities with which this or that outcome is obtained in a successful measurement.

The problem of making physical sense of the mathematical formalism of quantum mechanics is usually called "the measurement problem." In reality there are as many "measurement problems" as there are attempts to beat sense into the quantum formalism. For the priests, "to solve [the measurement problem] means to design an interpretation in which measurement processes are not different in principle from ordinary physical interactions," as an anonymous reviewer for a philosophy-of-science journal once put it to me.

I wonder what he (or she?) could possibly mean by an "ordinary physical interaction"? Quantum mechanics knows nothing about any physical mechanism or process by which value-indicating events are caused, or by which the probabilities it allows us to calculate are determined. A fortiori, it knows nothing about any mechanism or process by which physical systems interact. Interactions can only be described by their effects, and these are correlations between the probabilities of the possible outcomes of measurements performed on the interacting systems. The agenda of the priests is therefore bound to create a vicious circle.

In reality, to solve the measurement problem means to design an interpretation in which the central role played by measurements in the quantum theory is recognized and its ontological implications are understood. What does it tell us about the nature of our world

These are questions that ought to be addressed. Yet it is addressed by neither the agnostics nor the priests nor the don't-care faction. The agnostics have renounced ontology. The priests sweep the problem under the rug by denying the special role that measurements play in the quantum world. And the don't-care faction... doesn't care.

Curious!