How the Index Card Catalogued the World (2017) | Hacker News Reader

How the Index Card Catalogued the World (2017)

theatlantic.com

39 pointsTomte6 comments

Leibniz (who invented calculus as you learn it in school) invented a system where along each edge of each card was a row of squares with either a hole or a notch open to the edge. Each square corresponded to a category or property. To select all the cards that conformed to either of two categories, you stuck rods through the stack at the corresponding squares, and lifted: OR. For AND, you would use one rod and lift, and then again in the cards lifted, at the second position. For NOT, you use the cards left behind. So you could apply any arbitrary boolean expression to as many properties as you had squares on the edges. He meant to categorize everything in the world that way.

That method was used for searching in a data set for centuries, until punch-card sorting machines, and then computers. Index cards used to be essential for organizing anything.

I went from one end of Indonesia to the other looking for index cards, to make flash cards for vocabulary. They could not be had for love or money. But I finally found "visiting cards".

Honestly really got a kick out of reading about this. Human ingenuity!

https://en.wikipedia.org/wiki/Edge-notched_card

Related & recommended:

Paper Machines: About Cards & Catalogs, 1548-1929 By Markus Krajewski

> Why the card catalog — a “paper machine” with rearrangeable elements — can be regarded as a precursor of the computer.

https://mitpress.mit.edu/books/paper-machines

Factoid: the index card is not 3x5” but 75x125mm because Melvil Dewey was a strong proponent of the metric system.

Categorising between objects is what humans require to navigate the world and communicate observed difference but at what resolution does one re-think drawing lines between categories?

This is the root problem the whole world is grappling with IMHO.

Country borders? Gender lines? (Pick another...)?

At what point does a sibling become a new species. Is fungi more plant or animal. At what point is green on the colour spectrum.

How do we define the point as to when to stop drawing distinct lines and accept a certain "grey scale" while understanding that lines are required somewhere?

I think the social solution is market competition. Have several different people and standards bodies publish their categorization system for the world to judge, and whichever one becomes the most popular is the de-facto correct categorization to use. For example, most of the world has agreed to allow the United Nations to determine how many countries there are and who represents them on the world stage. Us software engineers generally agreed to allow IANA to categorize domain names. ISO gets to categorize date fields(ISO 8601) and IEEE tells us what floating point is (IEEE 754). They do the hard work and the rest of us just have to accept their proposals. Or, we can bring up our own, subjectively better ideas on how to split things.

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