Proponents and critics disagree about how to apply
Occam's razor. Critics argue that to postulate an almost infinite number of unobservable universes, just to explain our own universe, is contrary to Occam's razor.
[73] However, proponents argue that in terms of
Kolmogorov complexity the proposed multiverse is simpler than a single idiosyncratic universe.
[61]
For example, multiverse proponent
Max Tegmark argues:
[A]n entire
ensemble is often much simpler than one of its members. This principle can be stated more formally using the notion of
algorithmic informationcontent. The algorithmic information content in a number is, roughly speaking, the length of the shortest computer program that will produce that number as output. For example, consider the
set of all
integers. Which is simpler, the whole set or just one number? Naively, you might think that a single number is simpler, but the entire set can be generated by quite a trivial computer program, whereas a single number can be hugely long. Therefore, the whole set is actually simpler... (Similarly), the higher-level multiverses are simpler. Going from our universe to the Level I multiverse eliminates the need to specify
initial conditions, upgrading to Level II eliminates the need to specify
physical constants, and the Level IV multiverse eliminates the need to specify anything at all.... A common feature of all four multiverse levels is that the simplest and arguably most elegant theory involves parallel universes by default. To deny the existence of those universes, one needs to complicate the theory by adding experimentally unsupported processes and ad hoc postulates:
finite space,
wave function collapse and ontological asymmetry. Our judgment therefore comes down to which we find more wasteful and inelegant: many worlds or many words. Perhaps we will gradually get used to the weird ways of our cosmos and find its strangeness to be part of its charm.
[61][74]
— Max Tegmark
