The rationale for Rationale™

Complex reasoning and argumentation are central to legal practice. Software-supported argument mapping may be able to help lawyers reason and argue more effectively. This article describes Rationale™, a generic argument mapping software package, and reviews some evidence that using it can help improve reasoning, i.e. make people smarter. It then explores three different explanations for this potential benefit: usability, complementation and semi-formality. First, argument mapping software can be more usable for reasoning activities than traditional methods because it can inherit the wisdom gained through decades of research and experience into usability, can exploit a wider range of representational resources, and is designed specifically to support reasoning activities. Second, such software works by complementing the strengths and weaknesses of our natural or inbuilt cognitive capacities. Third, it helps shift reasoning and argumentation into a semi-formal mode, a kind of ‘sweet spot’ between the laxness of everyday reasoning and the straightjacket of formal logic.