Paul Meehl's famous critique laid out in detail many of the pathological practices and conceptual confusions that stand in the way of meaningful theoretical progress in psychological science. Integrating some of Meehl's points, we argue that one of the reasons for the slow progress in psychology is the failure to acknowledge the problem of coordination. This problem arises whenever we attempt to measure quantities that are not directly observable, but can be inferred from observable variables. The solution to this problem is far from trivial, as demonstrated by a historical analysis of thermometry. Also, it is not a problem that can be solved by empirical means. At its center is the need for a clear understanding of the functional relations between theoretical concepts and observations. In the case of psychology, the problem of coordination has dramatic implications in the sense that it severely limits our ability to make meaningful theoretical claims. We discuss several examples and lay out some of the solutions that are currently available.