9 min read

Consider the Platypus

How to find structure for your second brain.
Consider the Platypus
Photo by Meg Jerrard / Unsplash


Australians have a term that is perfect for the elusive platypus: bitsa.

Bits of this, bits of that.

The platypus is bits of duck, mammal, bird and reptile. There is nothing else like it in God’s kingdom.

A model of a fossil of a giant toothed platypus from the Riversleigh fossil fields. About a metre long and more than twice the size of platypus today.
Photo by David Clode / Unsplash

Once god completed creating all the animals, the big fella wanted to prove he had a sense of humour. So he made the platypus to make people piss themselves laughing.

So he grabbed the leftovers and placed this Frankenstein creature on the far side of the planet. Or so the old joke goes.

The poor platypus has suffered. There are the jokes, of course. Initially, they thought it to be a joke. And then there’s the near extinction.

It nearly died out because scientists didn’t know how to classify it. Was it a bird? A mole? No, it was a platypus.

Serious flaws emerged in the rigid hierarchies. The platypus broke the taxonomy of the day.

In managing our knowledge, we need to consider the platypus. It provides us with a few interesting observations. First, we can't approach it like an eighteenth-century scientist. They had that typical white male patriarchal approach. Basically, they were dicks. Second, we need to allow flexibility. It is a central skill our first brains have.

Why is there a need to manage our thinking? It's a good question. Also, a really old one. The reason libraries evolved is to collect and curate all of humanity’s knowledge. The first known library was in Ashurbanipal (modern day Iraq) in the 7th century B.C.

Wikipedia and Google are direct descendants of all of this managing of public knowledge. But our thinking, the internal monologue, is also in need of managing. Thoughts are associative and need to be connected to other thoughts if they are to stick.

One solution is to outsource some of this thinking to what Tiago Forte calls our "second brain". Now that technology is ubiquitous, it has never been easier to delegate the hard long-term thinking.

By considering the platypus, we can learn how to approach the management of our personal knowledge.


Platypi are native to eastern Australia and found only in freshwater lakes and streams. One lives about four hundred metres from my place. There is a viewing platform that looks out onto a tangle of grasses lining the creek's. Tucked away, somewhere, is the burrow. I've never seen a wild platypus. Only in zoos or a stuffed one in school.

When, in 1798, the scientific community in England examined the first specimen, they thought it to be a hoax. It was too bizarre. A duck's bill sown onto the body of a mole. Chinese taxidermists had pulled pranks like this before. A mermaid was “captured” off the Fijian islands and later exhibited by B.T. Barnum. A taxidermist had sown a monkey’s upper body onto the lower half of a fish’s. It is a hideous creation and not a sailor’s wet dream.

Once the platypus proved real, the quest was to classify this strange new creature. Carl Linnaeus’ system for classified according to observed similarities.

This scheme was clear:

  • Milk-producing animals who gave birth to live young were mammals
  • Warm-blooded animals that gave birth to eggs were birds
  • Cold-blooded egg layers were reptiles

The platypus didn't fit. It laid eggs AND produced milk to nurture the young.

This is a classic example when you only have a hammer, everything looks like a nail. The classification system wasn’t up to scratch. It wasn’t a mammal, a reptile, a duck, nor a bird. The scientific community was so hell-bent on classifying this mysterious creature, they almost drove it to extinction by killing platypus during breeding seasons so they could analyse its eggs.

The problem wasn’t with the platypus, but with the dogmatic hierarchical system that wouldn’t bend to reality. The trouble wasn’t the platypus; it was the way these men saw the world.


Humans are long-time masters of placing things into simple hierarchies. We inherited from our reptilian ancestors the simplest. Our basil ganglia assesses external stimulus using the four fs: fight, flight, freeze and fuck.

It’s a basic framework to keep us safe and happy. The challenge we are continually facing (subconsciously or not) is: do I need to run or hide, or can I fuck it?

Not always a straightforward question to answer. I’ve had a few ex-girlfriends whom I should have run from instead of... But that’s another story.

Basically, the basal ganglia is constantly scanning our surroundings, categorising everything into the schema. Thankfully, much of this sorting is automated for us. With one exception. The desire to fuck. That's a constant in your face thing. And don't the ad men exploit it.

Tiago Forte's concept of how to build a second brain also has four categories. Instead of determining if you should run from a potential mate, the P.A.R.A. system keeps our digital lives in order.

PARA Cheat Sheet

Let's look at a real world example. Fucking. You could create a Project so you could to take the dating thing seriously. This would mean taking a series of actions, such as downloading Bumble, writing the profile.

If you already had your life partner, you could make them an Area to ensure that the sparks still flew. Of course, their birthday could become a Project if socks or undies won't get you laid this year.

You could collect ideas for date nights or blog posts on the Kama Sutra and file them under Resources, or, if the relationship ended, well, you'd Archive it.

If only we could archive broken hearts. Life is messy and not easily forced into one of four boxes.

Try triaging your inbox and we all have platypi that defy simple hierarchies.


There are ways you can bend any hierarchy, including Tiago’s PARA system, so that it might accommodate bizarre creatures. Personal knowledge must allow for more flexibility. Maybe today’s platypus is a bird. Tomorrow’s could be a reptile.

How do you adhere to a system and allow for the platypi? Usually it'll mean breaking the system.

And for many, this leads to abandoning the entire organisation.

Then there are those who don't give a shit about taxonomies. They're saying “Who cares what a platypus is!?”

Two types of people ask this question. One group has yet to understand that power of organisation.

The second promotes the ideas of networks.


This group evades the up-front decisions of placing information into a schema. What they rely on is the promise of networked thinking to bring order to the chaos.

The proponents of this are selling snake oil. Networks only work if there are viable and long-lasting connections between the different nodes. Think of any public transport network in any city that doesn't work.

In this analogy, any time you need to rely on cars means the network isn't working. People are living too far from stations. These sprawling suburbs become the outer realms of your network.

It is true this approach requires less upfront cognitive load, but as with so much in life, you'll pay for it later on. It's like an all-you-can-eat buffet. Fill your plate up and figure out later how you'll eat it.


The problem with both hierarchies and networks is that they aren't optimal structures in and of themselves.

Let's reconsider the platypus. In 1809, Jean-Baptiste Lamarck published his Zoologie Philosophique. It was the precursor to the more famous 1859 work by Charles Darwin _On the Origins of Species_.

Lamarck argued that all living things could not only gain new traits, but could pass on those to future generations. Species evolved as we understand the concept.

It was now possible to classify according to evolutionary connections.

Because the platypus laid partially formed young, still in their egg, but to be suckled on milk glands, scientists now placed it (with the echidna) in a new class of vertebrates.

The platypus and echidna evolved very early on. They branched from the mammalian line when there were still reptilian characteristics.

French naturalist Étienne Geoffroy Saint-Hilaire named them Monotremata, meaning ‘one hole’. I’ll leave why to your imagination.


This new taxonomy allowed for placing all living creatures based on both similarities and evolutionary specialisation. It allows for both hierarchies and network thinking.

A heterarchy is the ability to approach knowledge from multiple directions.

Warren McCulloch first used the term heterarchy in a modern context in 1945. According to McCulloch, the human brain wasn’t organised hierarchically and yet still had order. A heterarchy is a system of organisation where everything has the potential to be linked. (which leads to an emergent and evolving hierarchy)

But how can we understand heterarchy’s of information? A compass to guide our knowledge management?

A dictionary is top down. It’s a hierarchy. Search only by words.

The encyclopedia is bottom up. It’s networked thinking. It listed multiple concepts under broader ideas.

But the Thesaurus? It’s a heterarchy. The same mindset that designed the thesaurus was the mindset that considered the platypus.


Let's consider the thesaurus.

The original purpose for Peter Mark Roget was to ‘facilitate the expression of ideas’. It isn’t a book of synonyms, which is a big misconception. It is a book of ideas. The thesaurus is a tightly wound ball that will take a dozen lifetimes to unravel.

Peter Mark Roget first published his Thesaurus in 1852. In the intervening one hundred and seventy years, it has sold over 30 million copies. With each new iteration, one thing is clear: Roget’s classification system has absorbed the massive expansion of the English language.

Unlike the original taxonomy for animals, Roget’s has yet to break. His taxonomy was flexible and accounted for new and bizarre ideas.

Roget condensed all the ideas of humanity into this one book, condensed into word associations, condensed into two parts: the plan of classification and the index. Like any house, there are two ways in. These two modes of entry make the Thesaurus a textbook-heterarchy.

The Classification System is the grand entrance, reserved for special guests and formal occasions. It has six “classes” framing everything. They range from ‘Abstract Relations’ to ‘Emotion, religion & morality’. Within each class, there are “sections” that move from really abstract concepts such as ‘1. Existence’ towards concrete objects like ‘990. Temple’, as if Roget’s structure bookends the forest from the tree, namely how we worship whatever existence we believe in. Only my temple is the classification system.

The index is how most people engage with the Thesaurus. It’s designed for quick visits and was an afterthought. The index is almost longer than the actual thesaurus. In my everyday thesaurus (yes, I collect thesauri) it is 426 pages, whereas the index is 398 pages long.

So let’s dive into the magic of the thesaurus, and that of heterarchy’s. Let’s take a word and see how it seeps into the system. Let's take the word 'horse'.

In the index, you find multiple listings.

  • The first being horse 273n. This falls under the classification of motion. It sits with cars and skateboards.
  • animal 365n is organic matter and pretty straightforward.
  • busy person 678n sits under voluntary action and is actually a Trojan horse in the sense of a busy bee.
  • cavalry 722n is with antagonism and then combatant
  • drug 949n judgingly is under morality as if being a junkie is a vice.

We can find all of this information in both a dictionary and an encyclopedia, but it’s one or the other. With a thesaurus, it's both.


Look at the platypus and the thesaurus - what do they have in common?

An ability to deal with the unknown & the unexpected. The main purpose of any second brain is to have a conversation with our future selves. And we don't know how a piece of information might apply to us next week, or next year.

In the dialogue with Meno, Socrates states that “a man cannot search either for what he knows or for what he does not know. He cannot search for what he knows — since he knows it, there is no need to search — nor for what he does not know, for he does not know what to look for.”

I am ashamed to quote Donald Rumsfeld after Socrates, but we need to account for that middle ground, the known unknowns.

Heterarchies are future proof - let the structure emerge organically while shape it to serve your thinking, both now and forever.

So, please, consider the platypus.