that makes so much sense! rabbit hole time…

one of the best nonfiction books i read was The Universal History Of Numbers by Georges Ifrah. years, even decades later, every now and then i learn a new thing about some linguistic quirk that ties back to what I learned from that book.

apparently, people (and some animals!) can instinctually and instantly “count” up to 4 objects! well, this is not actually counting, it’s just instantly knowing the quantity of a group of up to four items.

so if I showed you an image of 4 cubes flashed for a fraction of a second, and i ask you how many objects were in that image you’d probably have no problem saying four. once you get to 5 or more though it becomes very hard unless you can mentally group it into smaller chunks of 4 or less. the most obvious result of this is probably tally marks. the whole point of grouping in tally marks is to quickly be able to discern how many notches there are at a glance, so we put marks up to 4, and then a fifth one marks the end of the group for easy 5-by-5 counting except the fifth mark is usually put across the previous four, so you don’t have five marks in a row. that’s because it really becomes confusing once you go over 4. see if you have any trouble reading this “number” sequence:

I - II - IIII - I - III - IIII - II - IIII - I - III

pretty easy. now see if you have any trouble with this one:

I - III - II - IIII - I - IIIIII - II - IIII - I - II

chances are it was the sixth one that made you double take.

turns out this inherent ability we had way before math was even a thing naturally affected not only numeral systems but many aspects of language as well in different cultures.

you can find many cultural and linguistic features that suggest numbers up to 4 are more notable than 5 or more. in Latin for example a common practice was to give proper names to things up to the first four, and just use numbers for the rest. this may have included children, which is probably why you have names like Quintus, Sextus, Septimus, and most famously Octavius, named after the numbers 5-8.

they did the same with months of the year, the first four got named: #1 being March after the god Mars, April probably for spring (as it most likely comes from the verb “to open”), May after Maia the mother of Hermes, June after the god Juno. Then the rest were numbered: Quintilis, Sextilis, September, October, November and December, literally just the months #5-10. Quintilis and Sextilis would later be renamed after Julius and Augustus, which is why we don’t have those months numbered anymore but the bigger quirk is January and February being added to the front of the calendar, pushing March to 3rd position and the rest following it. so know we have a calendar that has months #9-12 named after numbers 7-10…!

while many languages have singular and plural, some languages can have specific forms for 2, 3 or 4 before getting to plurals for more. and here you can see Czech also having in some cases different rules for up to 4 things.