I started reading the abstract and thought immediately about Gregory Chaitin [1] measure of complexity, then searching on the text it is obviously there. I think it is a simple and good read to review Solomonoff–Kolmogorov–Chaitin [2] before reading the paper.

[1] https://en.wikipedia.org/wiki/Gregory_Chaitin

[2] https://en.wikipedia.org/wiki/Kolmogorov_complexity