But MWI is not the doctrine ‘everything exists’. This is a change of topic. Yes, if we live in a Tegmark universe and MWI is the simplest theory, then it’s likely we live in one of the MWI-following parts of the universe. But if we don’t live in a Tegmark universe and MWI is the simplest theory, then it’s still likely we live in one of the MWI-following possible worlds. It seems to me that all the work is being done by Ockham, not by Tegmark.
But MWI is not the doctrine ‘everything exists’. This is a change of topic. Yes, if we live in a Tegmark universe and MWI is the simplest theory, then it’s likely we live in one of the MWI-following parts of the universe. But if we don’t live in a Tegmark universe and MWI is the simplest theory, then it’s still likely we live in one of the MWI-following possible worlds. It seems to me that all the work is being done by Ockham, not by Tegmark.