 What then are the definite quantities and value states for a given system at a given time? Empirical adequacy requires that, in cases of measurement, the after-measurement value state of the measuring device should correspond to a definite measurement result. Therefore, the scheme minimally has to generate the Born probability measure over value states that represent the possible measurement results. Van Fraassen’s interpretation did not go further than this; it did not specify precise value states outside of measurement situations and defended agnosticism about the properties of physical systems in general (see Ruetsche 1996 for critical discussion concerning this point).