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R. Barrett and P. P. Delsanto
The concept of a multiverse in cosmology is still highly controversial. A
strong proponent, cosmologist Max Tegmark from the Massachusetts Institute of Technology and the Foundational Questions Institute, believes that
the multiverse is not a theory, but rather is predicted by a theory, and a widely
accepted one at that, namely the Concordance Model describing the inflation
of the early universe (see Chaps. 10 and 11). If we are prepared to believe
this theory for describing the evolution of the universe after the big bang,
we should be prepared to accept its other predictions, unless there is strong
evidence to the contrary [20].
Tegmark identifies four different levels of parallel universes within the
Multiverse. In a Level I parallel universe, observers experience the same laws
of physics that we do, but with different initial conditions, resulting in a
different history. In a level II universe, the fundamental physical constants
may also be different. This provides an explanation of the Anthropic Principle
that we have discussed earlier. A level III parallel universe involves quantum
effects, where every time a measurement is made, the universe splits into other
divergent universes (see Chap. 5). In a Level IV parallel universe, not just the
fundamental constants, but also the laws of physics are different from in ours.
In the absence of direct evidence of the multiverse, proponents are forced
to resort to indirect evidence, and this is where most of the controversy
and disagreement between different physicists arises. As we discussed in
Sect. 12.2, beauty is regarded by some as a sufficient criterion for the acceptance of a physical theory, even in the absence of corroborating observational
evidence. Others demand a much higher standard of proof.
Some claim that the refusal to accept a multiverse is another example of
anthropocentrism, the placing of our universe above all others, akin to the preCopernican period when the earth was thought to be the centre of the known
world. Their opponents dismiss the multiverse as the last resort of the desperate
atheist and an attempt to avoid the creationist implications of the anthropic
principle: i.e. the choice is between a multiverse and a creator, so take your
pick. The explanation it offers for the fine tuning of the fundamental physical constants is probably the strongest argument in favour of the multiverse.
Paul Davies has discussed the Anthropic Principle in detail in his book: The
Goldilocks Enigma [21].
One might conceivably raise Occam’s Razor (see Chap. 3) as an objection
to the multiverse. Surely postulating an infinite number of parallel universes
to explain our own is a flagrant violation of the good monk’s guideline.
Others counter this assertion with the argument that the multiverse eliminates the necessity to postulate precise values for initial conditions and
R. Barrett and P. P. Delsanto
The concept of a multiverse in cosmology is still highly controversial. A
strong proponent, cosmologist Max Tegmark from the Massachusetts Institute of Technology and the Foundational Questions Institute, believes that
the multiverse is not a theory, but rather is predicted by a theory, and a widely
accepted one at that, namely the Concordance Model describing the inflation
of the early universe (see Chaps. 10 and 11). If we are prepared to believe
this theory for describing the evolution of the universe after the big bang,
we should be prepared to accept its other predictions, unless there is strong
evidence to the contrary [20].
Tegmark identifies four different levels of parallel universes within the
Multiverse. In a Level I parallel universe, observers experience the same laws
of physics that we do, but with different initial conditions, resulting in a
different history. In a level II universe, the fundamental physical constants
may also be different. This provides an explanation of the Anthropic Principle
that we have discussed earlier. A level III parallel universe involves quantum
effects, where every time a measurement is made, the universe splits into other
divergent universes (see Chap. 5). In a Level IV parallel universe, not just the
fundamental constants, but also the laws of physics are different from in ours.
In the absence of direct evidence of the multiverse, proponents are forced
to resort to indirect evidence, and this is where most of the controversy
and disagreement between different physicists arises. As we discussed in
Sect. 12.2, beauty is regarded by some as a sufficient criterion for the acceptance of a physical theory, even in the absence of corroborating observational
evidence. Others demand a much higher standard of proof.
Some claim that the refusal to accept a multiverse is another example of
anthropocentrism, the placing of our universe above all others, akin to the preCopernican period when the earth was thought to be the centre of the known
world. Their opponents dismiss the multiverse as the last resort of the desperate
atheist and an attempt to avoid the creationist implications of the anthropic
principle: i.e. the choice is between a multiverse and a creator, so take your
pick. The explanation it offers for the fine tuning of the fundamental physical constants is probably the strongest argument in favour of the multiverse.
Paul Davies has discussed the Anthropic Principle in detail in his book: The
Goldilocks Enigma [21].
One might conceivably raise Occam’s Razor (see Chap. 3) as an objection
to the multiverse. Surely postulating an infinite number of parallel universes
to explain our own is a flagrant violation of the good monk’s guideline.
Others counter this assertion with the argument that the multiverse eliminates the necessity to postulate precise values for initial conditions and