Learnability Can Be Independent of ZFC Axioms: Explanations and Implications

In Ben-David et al.'s "Learnability Can Be Undecidable," they prove an independence result in theoretical machine learning. In particular, they define a new type of learnability, called Estimating The Maximum (EMX) learnability. They argue that this type of learnability fits in with other notions such as PAC learnability, Vapnik's statistical learning setting, and other general learning settings. However, using some set-theoretic techniques, they show that some learning problems in the EMX setting are independent of ZFC. Specifically they prove that ZFC cannot prove or disprove EMX learnability of the finite subsets on the [0,1] interval. Moreover, the way they prove it shows that there can be no characteristic dimension for EMX; and, hence, for general learning settings. Here, I will explain their findings, discuss some limitations on those findings, and offer some suggestions about how to excise that undecidability. Parts 2-3 will explain the results of the paper, part 4-5 will discuss some limitations and next steps, and I will conclude in part 6.