In current research and practice, deduplication is usually considered as a deterministic approach in which database tuples are either declared to be duplicates or not. In ambiguous situations, however, it is often not completely clear-cut, which tuples represent the same real-world entity. In deterministic approaches, many realistic possibilities may be ignored, which in turn can lead to false decisions. In this article, we present an indeterministic approach for deduplication by using a probabilistic target model including techniques for proper probabilistic interpretation of similarity matching results. Thus, instead of deciding for one of the most likely situations, all realistic situations are modeled in the resultant data. This approach minimizes the negative impact of false decisions. Moreover, the deduplication process becomes almost fully automatic and human effort can be largely reduced. To increase applicability, we introduce several semi-indeterministic methods that heuristically reduce the set of indeterministically handled decisions in several meaningful ways. We also describe a full-indeterministic method for theoretical and presentational reasons.