According to CNS, black holes may be mechanisms of universe reproduction within the multiverse, an extended cosmological environment in which universes grow, die, and reproduce. 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 theory 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 fine structure constant, the proton to electron mass ratio 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 would be expected to predominate in the multiverse. As with biological natural selection, mechanisms for reproduction, variation, and the phenotypic effects of alternate parameter heritability 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, by exploring the features with respect to these functions of the ensemble of possible universes that are adjacent to our universe in parameter space. Nevertheless, 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 CNS 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 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.
His theory has been critiqued on occasion (Vaas 1998; Vilenkin 2006), and continues to be elaborated and defended (Smolin 2001,2006). 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 our universe ensemble might be characterized as an extended, branching chain exploring a ‘phenospace’ of potential forms and functions within the multiverse.
CNS with intelligence (CNS-I) are models which attempt to bring intelligence and information theory into the CNS framework. They propose that accumulated end-of-universe, or more precisely, end-of-black-hole evolutionary intelligence may somehow aid in universe/black hole replication and selection within the multiverse. These models assume that any universe where emergent intelligence was able to play a less-than-random role in replication or selection might become replicatively favored, more resilient, or perhaps dominant in some multiversal environment, over lineages where emergent intrauniversal intelligence does not increasingly factor into replication, as in Smolin's original CNS model.
Some CNS-I models propose that increasingly internally intelligent universes might naturally grow out of simple CNS universes at the leading edge of universal complexity, just as we have seen intelligence emerge within environmentally dominant lineages in life's history on Earth. In the most functionally and morphologically complex species on Earth, we may observe that life's intelligence mechanisms have progressed from "random" recombination of prebiotic or prokaryotic genetic elements, to a much more culturally-guided replication in higher eukaryotes. In this process, we see that individual and collective intelligence (memes, knowledge, self-awareness) increasingly influences and constrains the original and persistent "random" replicators (genes, DNA).