...measuring the accuracy of individual components is probably near impossible, because accuracy is a multi-dimensional concept. how can you be sure you have measured every relevant variable.
Mrtennis - I agree with you that accuracy is a "multi-dimensional concept," in the sense that it refers to a number of variables, rather than a single variable. But I do not conclude from this that accuracy is impossible to assess. Consider the analogy with telescopes again...
A telescope's optics can suffer from various kinds of distortion, including spherical distortion, astigmatic distortion, and chromatic distortion. Hence the accuracy of a telescope is multi-dimensional, just like the accuracy of an audio component. The multi-dimensional nature of a telescope's accuracy makes it more difficult to assess, but not impossible. Similarly, the multi-dimensional nature of an audio component's accuracy makes it somewhat difficult to assess, but not impossible.
Having said that, I agree with you that the common measurements of an audio component's accuracy, like those that routinely appear in Stereophile, are unlikely to be exhaustive. In other words, there are probably some unknown variables that are relevant to the assessment of a component's accuracy. But even the likely presence of unknown variables doesn't vitiate the concept of accuracy in audio. It merely makes judgments about accuracy FALLIBLE. But that shouldn't be news to anyone.
also, if each component in a stereo system were accurate, does that imply that the stereo system is accurate?
IMO, yes. Assuming that you include the listening room as part of the assessment of a system's accuracy, and acknowledging that what inaccuracies do exist in the various components may interact in non-linear or unpredictable ways.
Bryon