Psychological experiments have shown that humans do not reason according to classical logic. Therefore, we might argue that logic-based approaches in general are not suitable for modeling human reasoning. Yet, we take a different view and are convinced that logic can help us as an underlying formalization of a cognitive theory, but claim rather that classical logic is not adequate for this purpose. In this chapter we investigate abduction and its link to human reasoning. In particular we discuss three different variations we have explored and show how they can be adequately modeled within a novel computational and integrated, cognitive theory, the Weak Completion Semantics.