tesler's law cover photo
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Legal UX

Tesler's Law: Understanding the Laws of UX and Legal Design

Explore Tesler's Law and its impact on legal design in this insightful article. Learn how complexity and simplicity intersect in user experience and contract design.
Bilgehan Arifoglu

Laws of UX and Legal Design: Tesler's Law

đź’ˇ People want more. People want to have more easily. You can't have both.

Welcome to the second episode of our Laws of UX series. This article will look at Tesler's Law and its relation to legal design.

What is Tesler’s Law

Tesler's Law, also known as The Law of Conversation of Complexity, states that for any system, there is a certain amount of complexity that can't be reduced by any means.

Removing functionality doesn't make something simpler because it eliminates options. Simplifying contracts by eliminating words and even clauses makes contracts inadequate. If you want to simplify things, you need to change the conceptual model of it.


While working for Xerox PARC in the mid-1980s, Larry Tesler realized how users interacted with applications was just as important as the application itself. The book Designing for Interaction by Dan Saffer includes an interview with Larry Tesler that describes the law of conservation of complexity. The interview is popular among user experience and interaction designers. Larry Tesler argues that, in most cases, an engineer should spend an extra week reducing the complexity of an application versus making millions of users spend an extra minute using the program because of the additional complexity. However, Bruce Tognazzini proposes that people resist reductions to the amount of complexity in their lives. Thus, users begin attempting more complex tasks when an application is simplified.

contract and complexity correlation

So even though you simply the contract, if you end up minimizing the contract, your work will be somewhat useless and may not meet the required expectation.

Illustration of an interior design of an airplane with 2 pilots on board.
Image by pch.vector on Freepik

When you look at the interior of an Airbus A380, a massive toy carrying 850 passengers, a novice sees complexity. A pilot sees various tools, each of which is simple to use.

Tesler’s Law and Legal Design

Take a moment and think about applying legal design principles to a trilateral treaty of obligations or market regulation contracts. These types of legal drafts are complex-by-design and complex by default. You can't simplify the whole part of the contract because it contains a higher level of legal or financial knowledge.

page of a complex contract
Sometimes you need to keep complexity in order to achieve the desired result and not to cause disharmony between the parties.

Simple doesn't equal minimal.

Suppose you're a data protection officer and regulate thousands of data from one of the most comprehensive data privacy management software such as OneTrust. In that case, you will see its complexity is essential to reduce the possibility of a data breach. You just can't simplify and make the product "minimal."

Imagine a complete workflow of OneTrust, Data Privacy Management Software. You can not simplify this software because you will eventually not simplify it, but rather minimize it. And this is not something we want to do.

Why Tesler’s Law Matters

Instead of simplifying the contract by applying legal design principles, you may cause essential parts of the contract to be missing and inadequate. Creating such a gap would be incompatible with legal design principles as it would not ensure the parties correctly understand the intended message.