Using First Principles Logic in UX Design

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In physics and other fields, an individual’s work is argued and reasoned from the position of First Principles. By using this mental model, an individual constructs their thought process from established foundational truths, not from assumptions or analogies. Entrepreneur, investor and engineer, Elon Musk, shares an example of this during an interview not long ago:

For those of you who skipped the video, first principles logic can be summed up like this: Rather than drawing conclusions or reasoning by analogy, first principles thinking is about breaking down a problem or idea to its fundamental truths, and then reasoning up from there to make decisions. In the video, Musk explains how he used first principles—versus others’ beliefs and opinions—to dissect the pricing landscape and viability of car batteries.

First principles thinking extends beyond the realm of physics; professionals in other fields like business and technology are adopting this framework to breakdown complex problems and drive innovation. This struck a chord in me, as I’m always looking for new ways to augment my own design process. So, here’s what I’ve learned about first principles and how they apply to design:


Why Do We Fall, Bruce?

As a UX designer, it doesn’t matter how well you can maintain control of a meeting. There’s an inevitable future where you’re in a room with your team and it turns into a design by committee quagmire. You’re having a healthy discussion considering many possible solutions for a problem, but it has gone on too long. And then, just like young Bruce Wayne toppling into a dark, dingy well, your user’s core needs are lost. Suddenly, you find yourself in a pit where everyone asks, “How did we get here?




In addition to that scenario, there’s a multitude of other digressions that may occur during the design process:

  1. You’re conducting research and begin asking the user too many speculative questions.
  2. Someone asserts that an untruth about the user is indeed true.
  3. Data collected from the user is re-interpreted by a teammate to meet their need. (i.e. Trying to make a circle square just to fit the design)

You get the picture, right?

When we see these issues occur, there are already ways for us to handle them. A typical and time-consuming solution is to fall back on what we’ve done before because it’s safe. Another is to point at collected data and say, “Well, the user said this.” But sometimes what the user says and what you learn during testing don’t coalesce.

But just like Bruce Wayne, you can pick yourself back up with first principles logic.


First Principles Example

Looking at Instagram, we could easily extract some foundational truths without even talking to users. Doing this allows us to look at various features of Instagram, analyze them using first principles logic and work our way up to rationalize their existence.

For example, let’s say someone says, “Enabling users to upload pictures through the UI is a terrible idea!”

Calmly, you identify first principles:

  • People take pictures to capture memories
  • Pictures are taken from cameras, computers and smartphones
  • Pictures are stored on cameras, computers and smartphones
  • People like to share pictures

Therefore, Instagram should enable users to upload pictures from these devices.

Easy, right?

If you bring this concept into your thought process or use it as a normal exercise with others, it helps tremendously. When applied to scenarios where there is too much gray area, opinions, muddied waters or a solution to a problem is overreaching — it should serve you well.

Unravel complexity. Clarify ambiguity. Fight ignorance.


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