The Eisler Value of a verse is a measure of how lax vs how strict the laws of physics are for that verse.
The higher the Eisler Value in a verse, the less strict a verse is. It was named for Jòs Eisler, a Hyperstarian born physicist who wanted to know why each Universe appeared to have different laws of physics. Verses can have different Eisler Values than the verses that contain them, but they can not have an Eisler value that is higher than the verse that contains them. For example, our Universe has an Eisler value of 5, but our Multiverse has an Eisler value of 6.
In 1958, in Hyperstaria, several astrophysicists (Among them, Jòs Eisler) at the New Sminonus observatory, were trying to figure out why certain Universes had very little timeline overlap. It was believed that Universes had infinite timelines and all behaved in the same way, so it would be logical that given infinite timelines, each Universe would have the same exact timelines.
The explanation at the time was that each Universe started out differently, and that was why they had turned out differently. However, this did not explain the discovered Universes that behaved seemingly randomly and numerous different classifications of Universes that seemingly behaved by their own set of rules.
To solve this issue, Eisler traveled to the Universe of Macîes to run experiments. He noticed that the formulas that had been proven for several decades, suddenly predicted the wrong outcome. This stumped Eisler, who conjectured that different Universes had different laws of physics.
After many more years of research in other Universes, he realized that the laws of physics not only differed between Universes, but the laws got added the deeper you went into the hierarchy of verses. Multiverses were considered to have fewer laws of physics than Universes. Metaverses were more lax than Multiverses. And this trend continued the further up you went.
Eisler developed a scale to measure how strict Verses are. The value on the scale is called the Eisler Value.