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Legal tech solutions must capture legal logic


Insa Janßen, LL.M. (UCLA) is Legal Lead at Legal OS. She studied law in Münster and subsequently completed her LL.M. in media law with a focus on negotiation strategy in Los Angeles. Insa Janßen is admitted to the bar in Germany and NYS. She joined Legal OS in December 2020 after working for three years in Munich at SKW Schwarz Rechtsanwälte in IT and data protection law, where she helped establish the Innovation Lab. She is also a visual artist and yoga teacher. These two professions contribute to her perspective and creativity, which she applies to the world of law.

Martin Bregulla is a legal engineer and research associate at Legal OS. He has been involved with the digitalization of legal services since his first state exam. Martin Bregulla initially worked as a Solutions Manager in the Legal Tech subsidiary of Osborne Clarke. He is currently a trainee lawyer at the Higher Regional Court of Cologne. At Legal OS, he provides strategic support to the sales and marketing teams through his own first-hand market experience.

Why traditional legal tech solutions aren’t enough

The barriers to adoption of legal tech are manyfold. Most of us will have heard about risk-averse legal professionals, data privacy and IT security concerns, or the alleged inefficiency of law firms’ billable hour business model. But one of the most significant challenges for legal tech providers is building software that works for lawyers, either by completely automating particularly arduous processes or by augmenting lawyers’ expertise to enable a new paradigm of efficiency and service quality.

The aim of any innovation project in legal teams is — amongst other things — to increase efficiency while maintaining quality standards. Innovation means rethinking things from the ground up, not simply reproducing the exact same output as before in a different way. Attempts at automating legal work thus far do not correspond with how lawyers think. Most solutions aim either to digitise existing legal processes or to more efficiently arrive at the same results as manual legal work (i.e. text documents). However, in order to meet the actual requirements of the way lawyers work, legal tech products must incorporate legal thought logic.

Legal logic as the basis for digitising legal work

Law is rule-based and these rules can be represented by code. In order to fully leverage the opportunities presented by digitisation, lawyers need technology that enables them to translate legal thinking into logic and code. Such technology should form the foundation of any approach to digitising legal work. A tool that cannot cope with the logical complexity of legal contexts will inevitably be inaccurate and ineffective when applied to complicated tasks.

Lawyers are already familiar with one widely adopted tool to map and convey legal logical structures: language. Language comes with its own set of limitations. An example is the word “or”. This single conjunction can denote three different logical links. As a tool, language offers lawyers the functionality to specify the exact logical links meant in a particular instance. Consider the three possible meanings of the following sentence:

“You can read this book or that book.”

  1. “Or” in the sense of mutual exclusivity (contravalence or exclusive disjunction) – i.e. “You can either read this book or that book.”
  2. “Or” in the sense of non-exclusivity (inclusive disjunction) – i.e. “You can read this book or that book or both”
  3. “Or” in the sense of exclusion – i.e. “You can read this book or that book or neither, but not both.”

The formulation of legal documents like contracts uses language to represent precise logical links. Therefore, software that automates the creation of legal documents must be able to represent all of those logical connections at least as precisely as language can. Therefore it is clear that a decision tree, which uses the linkage “or” without the possibility to differentiate between the 3 logical meanings, is insufficient.

The example above refers to propositional logic structures: the logical relationship between statements. In addition, the following logical operators are relevant for legal thinking and all have implications for legal tech requirements:

  • Class Logic – which describes the logical relationship between classes, i.e. groups, or “Bubbles” of elements.
  • Combinatorial Logic – Combinatorial structures represent possible variants of the interaction of different parameters. (Actually, this is why we need technology in law!)
  • Quantor (Quantifier) Logic – The logic that deals with quantified statements is called predicate logic or quantifier logic. Example: Some lawyers are smart.
  • (Alethic) Modal Logic – It’s the logic of possibilities! In the sense that it allows us to differentiate between: necessary – possible – impossible – unnecessary – contingent – determined – and the logical connection between these terms.
  • Deontological Logic – It’s the logic of obligation! (And kind of obvious, why it’s needed in legal thinking and technology)
  • Relational Logic – This logic deals with how two or more parameters relate to each other. Example (for an asymmetric relationship): The price paid for a Software (B) is reduced when uptime (A) is reduced. Uptime is not reduced / dependent upon prices paid.
  • Action Logic (This is interesting for anyone that gets excited by the idea of Smart Contracts!)
  • Syllogistic Logic – A syllogism is a three-part logical argument, based on deductive reasoning, in which two premises are combined to arrive at a conclusion. 
  • Fuzzylogical Structures – just a teaser – but this blows open how we can address indeterminate legal terms.

This is not an essay on legal logic. We are publishing a White Paper that will go into all details of technical and legal work related consequences of the abovementioned logical structures, so if this sparked your interest, you will be able to dive deeper. This essay is intended as a jumping off point for your creativity and a journey into the complexity needed for the true digital transformation of law. 

At the same time it is also a challenge to lawyers. The way we work on a daily basis often diverges substantially from solid logical thinking. For example, legal logic is often not (at least explicitly) part of the legal curriculum. 


The long-term truth that the legal profession is ill-prepared for digitisation, has become more obvious in recent years and even months. A real-world example of a defunct workaround is the Microsoft Word template, which includes the outcome of logical thinking but not the underlying logic itself. This is akin to showing the result of a calculation but not the working. There is no “why” embedded in the end result. In the best case, the lawyer working with the template might have the “why” in his or her head. If not, the usefulness of the template is inherently limited. It cannot easily be maintained, updated, or extended in domain coverage. Documentation of the crucial legal logic behind the template is either missing or crammed into comments in MS Word templates where it becomes frozen knowledge, destined to die.

Logical structures can be a framework for approaching legal work, both generally and with respect to technology. The beauty of this approach is that once you unpack the logic, you realise that you may have implicitly worked with it all the time. And where you have not, you find room for improvement and growth.

Insa Janßen and Martin Bregulla

Photo by Miguel Á. Padriñán from Pexels


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