Editing Fine-tuned universe (section)

=== Top-down cosmology ===
[[Stephen Hawking]] and [[Thomas Hertog]] proposed that the universe's initial conditions consisted of a [[Quantum superposition|superposition]] of many possible initial conditions, only a small fraction of which contributed to the conditions seen today.<ref>
{{Cite journal
 | last = Ball
 | first = Philip
 | authorlink = Philip Ball
 | title = Hawking Rewrites History...Backwards
 | journal = [[Nature (journal)|Nature]]
 | date = June 21, 2006
 | pages = news060619–6
 | url = https://www.nature.com/news/2006/060619/full/news060619-6.html
 | access-date = April 19, 2010| doi = 10.1038/news060619-6
 | s2cid = 122979772
}}</ref> According to their theory, the universe's "fine-tuned" physical constants are inevitable, because the universe "selects" only those histories that led to the present conditions. In this way, top-down cosmology provides an anthropic explanation for why this universe allows matter and life without invoking the multiverse.<ref>{{Cite journal | last1=Hawking | first1=S. W. | author-link1=Stephen Hawking | last2=Hertog | first2=Thomas |date=February 2006 | title=Populating the Landscape: A Top Down Approach | journal=Phys. Rev. | volume=D73 | page=123527 | arxiv=hep-th/0602091v2 | doi=10.1103/PhysRevD.73.123527 |bibcode = 2006PhRvD..73l3527H | issue=12 | s2cid=9856127 | url=https://cds.cern.ch/record/928933 }}</ref>