 Bridgman’s view on the complexity of nature also had a direct implication for the limits of operational analysis itself in providing clarity and precision. Right from The Logic of Modern Physics, Bridgman stressed that “all results of measurement are only approximate”; this obvious fact, he said, “tacitly underlies all our discussion”. This he attributed ultimately to something fundamental about the nature of human experience: “all experience seems to be of this character; we never have perfectly clean-cut knowledge of anything, but all our experience is surrounded by a twilight zone, a penumbra of uncertainty, into which we have not yet penetrated. This penumbra is as truly an unexplored region as any other region beyond experiment” (1927, 33). This indicated a fundamental limitation to the certainty of operations: “Operations themselves are, of course, derived from experience, and would be expected also to have a nebulous edge of uncertainty” (1927, 36). Bridgman remained clearly aware of the complexities revealed by operational analysis, stating late in his life that “operational analysis can always be pushed to the point where sharpness disappears” (Bridgman in Frank 1956, 78), and that “there is nothing absolute or final about an operational analysis” (Bridgman 1959b, 522). Still, he would not give up on the pushing, which was necessary to reach as much clarity as possible.