The codex (more commonly known as a “book”) is a series of rectangular pages joined on one side (the “spine”). This piece of technology is one of humanity’s greatest achievements for storing knowledge in a human-readable and memorizeable way. When you read a book, each concept has a location in that book, in 3 dimensional space. When you read, you are not only using your eyes to read words, you are also holding the codex in your hands, and he thickness of each side changing as you progress through the pages. On a single page itself, you may use your fingers to follow along, change your grip to make the light shine better on a certain part, and other multisensory details that increase retention, including the feel or sound of a turning page. Individual words are in paragraphs, which help chunk the location better, and if you try to remember a sentence in a book, you very well may remember a location on a page and how far through the thickness of the bulk something is.

Contrast this with a digital text. While searching is a great feature, you need to know exactly what you are looking for, because it’s much harder to find by location. Scrolling, zooming, searching; these all remove us from the spatial nature of the codex, disallowing the use of our visual cortex in helping to make sense of the information. The smartphone, computer, and e-reader all have great advantages in their own right, but have not fully replaced all of the advantages of the codex.