 The problem arises because of the interdependence of the accuracy of the measurement result and the accuracy of the measurement device: to know whether a particular measurement result is accurate, we need to test it against a measurement result that is previously known to be accurate, but to know that the result is accurate, we need to know that it has been obtained via an accurate measuring device, and so on. This, according to Collins, creates a “circle” which he refers to as the “experimenters’ regress”.