An external structure is needed to surpass the limitations of brain

We need a second brain to complement our natural brain. Our memories are finite, and our capacity to store information is limiting. The human brain is terrific when doing what it is supposed to do. But when you force it to be used as an information process storage tank, it fails. Our brains are good for two things making decisions and pattern matching (or linking)

External systems help our brain offload the stuff being thrown into a reliable place. Methods such as GTD use it to empty a stream of information so that you can make a decision later when you are free to process the information.

GTD functions as an extended memory system to keep track of the things that are important to us. GTD helps us make better decisions without being overwhelmed by the storage of this information.

But as a second brain, Zettelkasten goes beyond that. It is not just a place to offload information. It is designed in such a way that the offload occurs contextually. Zettelkasten not only helps you with decision-making but also with pattern matching. It becomes a place for you to play with ideas so that you can connect the ones you feel will fit.

It becomes a conversation partner.

The similarity between GTD and Zettelkasten is that they are both external systems, and offloading stuff into them requires considerable habit development. GTD takes less overhead when it comes to decision making while Zettelkasten is more taxing that way as you are making decisions right from the moment you are reading something. This initial taxation will pay its dividends in the long run as you can generate new novel connections and thus become perfect examples of how [[ Constraints breeds creativity ]] and the power of [[ forcing function ]]s. It becomes ingrained [[ Essentialism ]] in a way.

Related: [[ Difference between Zettelkasten and GTD ]]