Cosmological natural selection (fecund universes)
Cosmological natural selection, also known as fecund universes, is a theory of eminent theoretical physicist and quantum gravity scholar Lee Smolin.
Universe reproduction via black holes
According to Smolin's theory, black holes may be mechanisms of universe reproduction within an extended cosmological environment called the multiverse. Rather than a ‘dead’ singularity at the center of black holes, a point where energy and space go to extremely high densities, what occurs in Smolin’s CNS model is a 'bounce' that produces a new universe with parameters stochastically different from the parent universe. Smolin theorizes that these descendant universes will be likely to have similar fundamental physical parameters to the parent universe (such as the speed of light, the Planck constant, the gravitational constant, the electric constant, the cosmological constant and others) but that these parameters, and perhaps to some degree the laws that derive from them, will be slightly altered in some stochastic fashion during the replication process. Each universe therefore potentially gives rise to as many new universes as it has black holes.
In a process analogous to Darwinian natural selection, those universes best able to reproduce and adapt will predominate in the lineage. As with biological natural selection, mechanisms for heritability and variation may be modeled. With respect to adaptation, selection for a range of proposed universal fitness functions (black hole fecundity, universal complexity, etc.) may be tentatively tested with respect to present physical theory (for example, by exploring the ensemble of possible universes adjacent to our universe in parameter space), though strategies for validating the appropriateness of fitness functions remain unclear, at present, as do any hypotheses of adaptation with respect to the multiverse, other universes, or other black holes.
Smolin states that his theory originated as an attempt to explore the fine tuning problem in cosmology via an alternative landscape theory to string theory, one that might provide more readily falsifiable predictions. According to The Life of the Cosmos (1997), his book on CNS and other subjects for lay readers, by the mid-1990’s his team had been able to sensitivity test, via simple mathematical simulations, eight of approximately twenty apparently fundamental parameters. In such tests to date, Smolin claims our present universe appears to be fine tuned both for long-lived universes capable of generating complex life and for the production of hundreds of trillions of black holes, or for ‘fecundity’ of black hole production.
McCabe (2006) states that research in loop quantum gravity “appears to support Smolin’s hypothesis” of a bounce at the center of black holes forming new universes (see also Ashtekar 2006). If true, such a mechanism would suggest an organic type of reproduction with inheritance for universes, and the universe ensemble might be characterized as an extended, branching chain exploring a ‘phenospace’ of potential forms and functions within the multiverse.
Brief Antecedents to Smolin's Theory
In an update of the oscillating universe model of Alexander Friedman (1922), John A. Wheeler (1973,1977) proposed that the basic laws and constants of the universe might fluctuate randomly to new values at each successive bounce (new universe birth), and thus provide a natural mechanism for anthropic selection. The oscillating universe theory persists today as the cyclic model in brane cosmology. The theory remains controversial as no satisfactory description of the bounce has been developed in string theory. In addition, recent empirical evidence that universal expansion is not slowing but is accelerating (observation of distant supernovae as standard candles, and the well-resolved mapping of the cosmic microwave background), suggest that a future big crunch is unlikely. Nevertheless, such an ultimate scenario cannot yet be ruled out entirely, as the nature of the dark energy that drives universal acceleration is not yet known.
Beginning in the 1980’s theorists in quantum gravity began postulating that our universe might ‘give birth’ to new universes via fluctuations in spacetime over very short distances (Baum 1983; Strominger 1984; Hawking 1987,1988,1993; Coleman 1988). Some theorists (Hawking 1987; Frolov 1989) proposed that new universe creation might be particularly likely in the singularity region inside black holes.
As Victor J. Stenger observes (1999), Quentin Smith (1990) independently proposed that random symmetry breaking events in the initial Big Bang singularity, and in black hole singularities that form in universes of our type, might lead to the production of new universes via black holes, and this could provide a naturalistic explanation for the emergence of the basic laws and constants of our universe.
- Meduso-Anthropic Principle
- Selfish Biocosm Hypothesis
- Misner, Charles, Thorne, Kip and Wheeler, John A. (1973) Gravitation, W.H. Freeman, pp. 1196-1217.
- Smith, Quentin (1990) A Natural Explanation of the Existence and Laws of Our Universe (html). Australasian Journal of Philosophy 68:22-43.
- Smolin, Lee (1992) Did the Universe Evolve? Classical and Quantum Gravity 9:173-191.
- Smolin, Lee (1994) The fate of black hole singularities and the parameters of the standard models of particle physics and cosmology (PDF). arXiv:gr-qc/9404011v1
- Smolin, Lee (1997) The Life of the Cosmos (Amazon), Oxford U. Press. ISBN 0195126645
- Smolin, Lee (2001) Three Roads to Quantum Gravity (Amazon), Basic Books. ISBN 0465078362
- Smolin, Lee (2006) The status of cosmological natural selection (PDF). arXiv:hep-th/0612185v1
- Stenger, Victor J. (1999) The Anthropic Coincidences: A Natural Explanation (html). The Skeptical Intelligencer Vol. 3(3).
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