 How this process avoids vicious circularity becomes clear when we look at it either “from above”, i.e., in retrospect given our current scientific knowledge, or “from within”, by looking at historical developments in their original context (van Fraassen 2008: 122). From either vantage point, coordination succeeds because it increases coherence among elements of theory and instrumentation. The questions “what counts as a measurement of quantity X?” and “what is quantity X?”, though unanswerable independently of each other, are addressed together in a process of mutual refinement. It is only when one adopts a foundationalist view and attempts to find a starting point for coordination free of presupposition that this historical process erroneously appears to lack epistemic justification (2008: 137).