A good argument against the multiverse, or infinitely many concurrent universes, is the singular experience of consciousness. If conscious experience is the result of my brain state and if there are infinitely many universes, my brain state should be replicated infinitely many times across universes and I should have infinitely many concurrent experiences of consciousness. I do not observe this, therefore one of the premises is false. Either there aren’t infinitely many concurrent worlds, or consciousness isn’t a product of brain state.
To the degree that I find independent credence in one premise, then the other will disproportionately lose credence. I see some evidence that brain state matters for my conscious experience, so I heavily lose credence in the reality of many concurrent worlds. Note that this argument still allows that there may be many worlds in some special arrangements:
- A series of universes that may be finite or infinite in number, and cyclical or acylical in nature, so long as only one exists at any point in time.
- A set of parallel worlds with some interrelation such that my brain state uniquely and regularly exists in only one member of the set.
- A combination of the prior two.
- March 2022, We Don’t Live in a Simulation
- March 2020, For and Against the Multiverse
- March 2018, Materialism and Reincarnation
- July 2015, Big Bounces are Anthropic Too