Intro: Our universe has profoundly fine tuned constants that as of yet aren't emergent from any mathematical model we have. The standard model relies on measuring these constants experimentally to work. The cosmological constant is fine tuned to 3 parts in 10^120 which is a surprisingly accurate number. The whole set of fundamental constants that make life possible is staggering and has allowed skeptic thought to invoke the idea of multiverses to do away with the invocation of a cosmic designer that allow these constants. Somehow, we just can't think that life dictates the creation of the universe and not the other way round. Why is space 3 dimensional, why is the gravity constant exactly what it is?

The skeptical solution: There are various kinds of multiverses that exist. Some emerge from quantum mechanical laws (but who put the quantum mechanical laws there in the first place? This is enough to doubt everett's multiverse). Others are part of an eternally inflating universe. Our own universe which was once thought by Galileo to have no special frame of reference might have one. Our galaxy cluster is moving towards a region of space and we call this flow the Dark flow. Maybe it's the pull from a galaxy cluster beyond our particle horizon now or maybe, just maybe it's another bubble universe validating the idea of eternal inflation.

The idea of multiverses has profound philosophical implications which are scary IMO. A large number of people believe that math is fundamental reality and the universe is a manifestation of logic and reason. We use it with staggering success so there's less reason to doubt it. However if the multiverse theory is true, then it could mean that other types of logic exist that are beyond our capability to comprehend which lead to unknowable truths. The truths we discover with out math might be false in another universe where physics works differently. This notion kills the idea of absolute truths.