This is called "
The many-worlds_interpretation"
It is always important to understand why theories are proposed. This one is subtle. Read the first paragraph in the link above, "The
many-worlds interpretation is an
interpretation of quantum mechanics that asserts the
objective reality of the
universal wavefunction and denies the actuality of
wavefunction collapse. " Wavefunction collapse is the key in this sentence. It is important to understand that wavefunction collapse is itself a theoretical concept, having to do with, how do we get a classical world from a quatum mechanical world?
Once you understand that sentence and bring it into
focus from a scientific point of view, the suggestion of the MWI makes more sense.
My opinion is that it is silly. That doesn't mean I think that the
Multiverse is silly though. That is almost as hard for most people to swallow as the MWI, but I see no way out of the fine-tuning needed to create a universe that appears perfect in every way for life as we know it. The videos above go into it some if you haven't looked at them.
In these videos that I continue to post, it is essentially asking this one question:
Why is the universe so perfect for life? Almost all directions point that this universe is not unique. Each theory posits a different way to get "infinite universes"