Book Summary & Highlights: Subtract: The Untapped Science of Less By Leidy Klotz

Book Summary & Highlights: Subtract: The Untapped Science of Less By Leidy Klotz



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Amazon Summary

We pile on “to-dos” but don’t consider “stop-doings.” We create incentives for good behavior, but don’t get rid of obstacles to it. We collect new-and-improved ideas, but don’t prune the outdated ones. Every day, across challenges big and small, we neglect a basic way to make things better: we don’t subtract. Leidy Klotz’s pioneering research shows us what is true whether we’re building Lego models, cities, grilled-cheese sandwiches, or strategic plans: Our minds tend to add before taking away, and this is holding us back.

But we have a choice―our blind spot need not go on taking its toll. Subtract arms us with the science of less and empowers us to revolutionize our day-to-day lives and shift how we move through the world. More or less.

About Author

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Other Book Summaries

Less Wrong


Klotz’s central argument is that individuals and societies systematically neglect subtraction as a means of change, and that this leaves plenty of low-hanging fruit for those willing to embrace it.

Good science

In a mid-replication crisis world, we should be very skeptical of pop-psychology books purporting to show the importance and universality of some (even mildly) counterintuitive phenomenon. Leidy Klotz, who is officially a professor of engineering but whose research is genuinely interdisciplinary, preempts this critique by documenting his long and laborious path to establishing “subtraction neglect” as a genuine phenomenon.

My favorite line of the book:

‘We need to go from can we believe that people neglect subtraction to must we believe that this is the case’
Only the first chapter of Subtract is based on Klotz’s original research. In the rest of the book, he draws together evidence from biology, psychology, economics, and history, interwoven with personal narrative and historical anecdotes, to explain first why we neglect subtraction and how embracing subtraction can help us as individuals and improve society.

Why We Add

Signaling Competence

Chapter 2, “The Biology of More,” could have come straight from Robin Hanson and Kevin Simler’s The Elephant in the Brainthat is, aside from the fact that Klotz uses the phrase “showing competence” in place of “signalling.” Both works use the bowerbird as an illustrative example; thanks to sexual selection, male bowers spend lots of time and energy building elaborate nests that never get used simply to “provide visible proof [to potential mates] that the builder has good genes.” Klotz (and Hanson and Simler and I) thinks humans aren’t much different: The problem is that it can be harder to show competence by subtracting….No matter how beneficial an act of subtraction is, it’s not likely to leave as much evidence of what we’ve done.
longer blog posts get linked to and shared more often.


Much as our inclination to overeat was advantageous in the premodern world, our instinct for addition was adaptive when resources of all kinds—clothes, food, tools—were scarce and costly to create. Hoarding behavior, after all, is common in other mammals.

Innate Ability To Add Better Than To Subtract

As it turns out, young children who cannot perform arithmetic are still quite able to estimate the results of addition and subtraction problems. And, as you can probably guess by now, they’re much better at the former.



Klotz recounts the historical evidence that monumental architecture is not a mere aesthetic novelty or even a result of civilization, but a primary cause of civilization.


The argument goes like this: “material culture,” the social and cultural meaning attributed to physical items, enables cooperation and social organization at large scales. Whereas in small bands (<=Dunbar number) of hunter-gatherers, “everyone could learn one another’s traits, skills, and favored cuts of mammoth meat,” larger groups needed a symbolic organization system to do the same. For instance, the material and style of one’s clothes would begin to indicate profession, wealth, religion, or other socially-important characteristics. This, in turn, gave people reason to accumulate things that were useful for indicating a desired characteristic. Klotz doesn’t say this explicitly, but intuitively it seems that more would generally come to indicate wealth, status, and other ‘good’ things. Buying or making something—particularly something non-functional like jewelry—is a credible signal that one has time and money to spare. As a side note (from me, not Klotz), this has reversed to some extent in the modern world. Just as thinness is high-status in a world of abundant calories even for the poor, the minimalist aesthetic exemplified by Marie Kondo et al is high-status in a world where even relatively poor people (in the developed world, at least) can accumulate lots of material goods.


Perhaps the most convincing cultural cause of addition is writing. Writing, and information storage in general, asymmetrically favors creation. This is true both for information itself and for physical items. It facilitates trade and general economic production, feeding the interpersonal arms race of material culture. It empowers governments and other institutions to bring people together at a larger scale. It makes storing information easy, and disposing of it unnecessary. It’s a bit odd to me that Klotz only gives writing a few paragraphs—much fewer than monumental architecture— since it seems particularly important to me.

The field and the objects

The most speculative argument in this section, Klotz suggests that cultural promotion of independence encourages us to neglect subtraction. Like me, you may have heard that people in Asian cultures tend to psychologically emphasize their role in relationships (e.g. teacher of my studentsJane’s friend, brother of Maria), whereas Westerners tend to conceptualize individual attributes as central and relationships as ancillary. Apparently, this extends beyond the interpersonal world; some cultures, like those of coastal cities in the U.S., emphasize “objects,” whereas others, like Chinese Confucianism, emphasize the surrounding “field.” None of this is controversial, but Klotz goes on to speculate that field-oriented understanding enables subtraction in a way that object-oriented thinking does not. In his words, a “focus on individual objects [causes us to]…fail to consider taking them away from the surroundings.”


Klotz opens this chapter with the personal anecdote I found most memorable. In the midst of writing the book, he and his wife decided to renovate their home. Inspired to see what subtraction had to offer, he solicited “Addition by Subtraction” design proposals from his architecture and engineering students, with the best submission to receive a $1000 prize. Despite his genuine commitment to the task, Klotz admits that he never removed anything from his existing house (which, recall, would be distinct from minimalist or simplistic design). The reason is simple: house valuation increases with square footage, and he couldn’t justify spending money to decrease the value of his house. Even if he, his wife, and his kids all appreciated the removal of some space or feature, the market’s invisible hand would only punish them for the decision.


The author’s more general point is that economic growth has become a key socio-political goal. And, of course, economic production asymmetrically favors addition.
People take on meetings and appointments “not because they [are] required to but because they [feel] it would be socially unacceptable not to.” “Busy” has become a boastful signal, indicating that we are in-demand and willing to take on the challenge. The more we work, the more we are rewarded with money and status.
Opportunity cost is invisible. When we add materially by purchasing, we don’t immediately see what that money could have been used for instead. We can see the concrete, tangible output from adding (and completing) a task on the to-do list, but can’t so easily discern the stress-relieving, slack-enabling benefits associated with the free time created from task removal or refusal.

Political Economy: Assymetrically easier to add than to remove

A related point is that addition creates entrenched, concentrated stakeholders in a way that subtraction does not. The beneficiaries of a new action or policy often become a potent constituency for its maintenance and expansion. On the other hand, the benefits associated with subtraction, like a slight decrease in price from the removal of a burdensome regulation, are often more diffuse and less salient.

Putting it into Practice

  1. Subtraction should be a means of improvement, not an end in itself.
  2. Make subtraction noticable
  3. Use semantics that have a more positive valence than subtraction (reveal, clean, streamline) - "Marie Kondo, for example, doesn’t implore us to “get rid of useless shit,” but rather “to keep only what sparks joy.”

Subtraction for Systematic Change


Invert: Try less before more…don’t “subtract.” Instead, clean, carve, and reveal.
Expand: Think add and subtract…Adding should cue subtracting, not rule it out…So sure, add diversity, but subtracting racism is the prize.
Distill: Focus in on the people…Strip down to what sparks joy…Subtract information and accumulate wisdom
Persist: Keep subtracting. Can you make less undeniable. Bruce Springsteen made Darkness visible. Costa Rica made neutrality noticeable.



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Symptoms You Are Over-Adding

  • Do your resolutions more often start with “I should do more of…” than with “I should do less of…”?
  • Do you have more stuff than you used to?
  • Do you spend more time acquiring information—whether through podcasts, websites, or conversation—than you spend distilling what you already know?
  • Do you spend more time writing new content than editing what’s there?
  • Have you started more organizations, initiatives, and activities than you have phased out?
  • Do you add new rules in your household or workplace more often than you take rules away?
  • Do you think more about providing for the disadvantaged than about removing unearned privilege?
  • Are you busier today than you were three years ago?
If you answered yes to any of these questions, you’re not alone. In our striving to improve our lives, our work, and our society, we overwhelmingly add. As we’ll see in the pages to come, there are many interwoven reasons for this—cultural, economic, historical, and even biological. As we’ll also see, it doesn’t have to be this way. To be sure, sometimes more is better. When my family returned from our trip to San Francisco, we spread out in a home with a new five-room addition. In other cases, adding makes sense in isolation but crowds us over time, such as when the first floor of our home addition filled with tens of thousands of Legos. And sometimes taking away brings delight. No longer is my running confined to a treadmill, from which I used to listen to books and podcasts while watching the news on television, leaving my brain with no chance to turn data to knowledge to wisdom. The rewards of less came only after evidence honed my thinking about how to get there.

Subtraction Definition

Subtracting is an action. Less is an end state. Sometimes less results from subtraction; other times, less results from not doing anything. There is a world of difference between the two types of less, and it is only by subtraction that we can get to the much rarer and more rewarding type. In other words, subtraction is the act of getting to less, but it is not the same as doing less. In fact, getting to less often means doing, or at least thinking, more. Removing a freeway is far more challenging than leaving it alone or than not building it in the first place. As my team would find in our studies, mental removal requires more effort too. So, subtractors need not be minimalists, laid-back, anti-technology, or possessed of any other philosophy that owes some of its popularity to its ease. In fact, when we mix up these other philosophies with subtraction, we don’t see taking away as an option, and we discount the hard work needed to make it happen.

Competence Bias: We do things where we feel competent

In 1959, Harvard University psychologist Robert W. White took a step toward connecting file folders with evolution. In a paper that has been cited more than ten thousand times, White described our “intrinsic need to deal with our environments”—not just for survival but to avoid feeling helpless. White defined his key idea with one word, competence, meaning how well we feel we are dealing with our world. In 1977, the Stanford University psychologist Albert Bandura extended White’s idea, concluding that one way we meet our intrinsic need to feel competent is by successful completion of tasks. Our biological need to deal with our world is also why it feels good to check items off of a list (and to complete yet another draft of a paper). Why would our intrinsic need to feel competent work against subtracting? After all, Ezra learns about his world when he takes away Legos just as well as when he adds them. It’s true; we can develop competence just as well by subtracting. The problem is that it can be harder to show competence by subtracting. When we transform things from how they were to how we want them to be, we need proof—to show mates, competitors, and ourselves. Adding a freeway or file folder shows the world what we did. But just as the Embarcadero Freeway has disappeared from San Francisco’s waterfront, there is no proof of the few shared file folders I managed to prune. No matter how beneficial an act of subtraction is, it’s not likely to leave as much evidence of what we’ve done.

Case Studies

Addition Not Working

  • Bloated policies and rules
  • Bloated products

Subtraction Working

  • Sue Bierman subtracted a freeway to create one of the most visited places in the world.
  • Leo Robinson sparked the financial subtraction that brought down apartheid.
  • Elinor Ostrom subtracted wrong ideas to give humanity a better approach to our common future.
  • Da Vinci defined perfection as when there is nothing left to take away
  • William of Ockham noted that it is “in vain to do with more what can be done with less,”
  • Lao Tzu advised: “To attain knowledge, add things every day. To attain wisdom, subtract things every day.”