Conclusion

Defeasible reasoning is a key aspect of legal reasoning and problem-solving. Therefore, theories and logics of defeasible can greatly contribute to the study of legal argumentation and legal justification.
Recognising the strength of the connection between defeasibility and the law does not require abandoning logical rigour. On the contrary, it favours adopting logical models that precisely match certain important structures of legal knowledge, certain frequent patterns of legal reasoning, and of the dialectics of legal interaction. Argument-based theories of defeasible reasoning provide the most advantageous approach to address defeasibility in legal contexts.
I have argued that legal theory should addressed defeasibility using a shared conceptual framework and focus with the other disciplines — in particular, logic and computing— which have so far addressing defeasible reasoning. This does not exclude that the legal theory can provide useful contribution to the study of defeasibility. In fact, the law provides a rich set of structures and patterns for defeasible reasoning. Therefore, the analysis of patterns of defeasibility in the law can contribute not only to legal theory and (computable) legal logic, but also to the development of general theories and logical models of defeasibility.