Abstract
This article investigates epistemological aspects of scientists’ reuse of empirical data over decades and centuries. Giving examples, I discuss three respects in which empirical data are historical entities and the implications for the notion of data reuse. First, any data reuse necessitates metadata, which specify the data’s circumstances of origin. Second, interpretation of historical data often requires the tools of humanities disciplines, which produce a further historicization of data. Finally, some qualitative social scientists hold that data are personal to the researcher who coconstructs them in the research process and are therefore skeptical about the prospects of reusing data.