Your collection of linked notes, your Zettelkasten, isn’t a ‘second brain’, as though it were separate from your first, actual brain. Rather it is part of your extended mind, which your brain creates constantly by co-opting its wider environment into its own processing activity. Brain and environment together create mind. In the case of the Zettelkasten it’s a very deliberate extension of the brain, with a few simple but powerful generative rules.

One of the interesting features of this deliberately extended cognitive tool is its ability to present you with surprises. Reading through old notes, for example, you may be surprised that you ever wrote this. And re-reading your work in the light of new information, you may have new flashes of inspiration or see new connections that weren’t previously visible. Or perhaps the juxtaposition of two seemingly unrelated notes will prompt you to create a third, which contains an entirely new idea.

In this sense, your notes become a kind of conversation partner, reminding you of what you once thought, and even challenging you to go further. It’s a living thinking environment, an ever-evolving ‘connectome’, which sometimes appears to have a life of its own.

Why not surprise yourself?

Philosopher Andy Clark is quite well known for claiming that the human mind extends beyond the brain, and that “human brains spawn and maintain extended human minds”.

In a podcast interview with Sean Carroll, he recommends artificially curating environments in which we can surprise ourselves. This temporary increase in uncertainty, he claims, reduces prediction error in the long term.

“it looks as if very often, the correct move for a prediction-driven system is to temporarily increase its own uncertainty so as to do a better job over the long time scale of minimizing prediction errors, and that looks like the value of surprise, actually, and that we will… I think we artificially curate environments in which we can surprise ourselves. I think, actually, this is maybe what art and science is to some extent, at least, we’re curating environments in which we can harvest the kind of surprises that improve our generative models, our understandings of the world in ways that enable us to be less surprised about certain things in future.”

Clark refers to the work of Karin Kukkonen, a literary scholar who has applied the idea of predictive processing to literature. This reminded me of Steven Johnson’s suggestion in his book, Farsighted that a good novel is a decision-making simulation. He extolls the sophisticated decision-making conundrums of the characters in George Eliot’s Middlemarch, over the simpler black-and-white decisions of Charles Dickens' characters.

So perhaps the surprise function of the Zettelkasten is more useful than at first appears. It isn’t merely an aid to memory, or a handy conversation partner, or a writing prompt. On Clark’s account, it may also enable precisely the kind of surprises we need and can learn from in order to understand the world better.

Of course, we constantly encounter surprises in everyday life, and sometimes learn from them too. But viewed through the ‘predictive, extended mind’ lens, the Zettelkasten presents a precise, controlled and deliberate laboratory for cultivating such a learning process.

I wonder how your notes have surprised you. Please let me know.

Some resources

Andy Clark on the Extended and Predictive Mind - [Sean Carroll’s Mindscape: Science, Society, Philosophy, Culture, Arts, and Ideas] (

Clark, Andy. 2022. Extending the Predictive Mind, Australasian Journal of Philosophy, DOI: 10.1080/00048402.2022.2122523

Johnson, Steven. 2018. Farsighted : How We Make the Decisions That Matter the Most. New York: Riverhead Books an imprint of Penguin Random House LLC.

Kukkonen, Karin. 2020. Probability Designs: Literature and Predictive Processing. Oxford: Oxford University Press. ISBN: 9780190050962

See also

A network of notes is a rhizome not a tree

How to connect your notes to make them more effective

The mastery of knowledge is an illusion