The implication is that information transfer from the parent universe into the baby universe through a black hole is not conceivable. Smolin has noted that the string theory landscape is not Popper-falsifiable if other universes are not observable. This is the subject of the Smolin–Susskind debate concerning Smolin's argument: "[The] Anthropic Principle cannot yield any falsifiable predictions, and therefore cannot be a part of science." There are then only two ways out: traversable wormholes connecting the different parallel universes, and "signal nonlocality", as described by Antony Valentini, a scientist at the Perimeter Institute. In a critical review of The Life of the Cosmos, astrophysicist Joe Silk suggested that our universe falls short by about four orders of magnitude from being maximal for the production of black holes. In his book Questions of Truth, particle physicist John Polkinghorne puts forward another difficulty with Smolin's thesis: one cannot impose the consistent multiversal time required to make the evolutionary dynamics work, since short-lived universes with few descendants would then dominate long-lived universes with many descendants. Smolin responded to these criticisms in Life of the Cosmos and later scientific papers. When Smolin published the theory in 1992, he proposed as a prediction of his theory that no neutron star should exist with a mass of more than 1.6 times the mass of the sun. Later this figure was raised to two solar masses following more precise modeling of neutron star interiors by nuclear astrophysicists. If a more massive neutron star was ever observed, it would show that our universe's natural laws were not tuned for maximal black hole production, because the mass of the strange quark could be retuned to lower the mass threshold for production of a black hole. A 1.97-solar-mass pulsar was discovered in 2010. In 2019, neutron star PSR J0740+6620 was discovered with a solar-mass of 2.08 ±.07. In 1992 Smolin also predicted that inflation, if true, must only be in its simplest form, governed by a single field and parameter. This idea was further studied by Nikodem Poplawski. See also Black hole cosmology Biocosm Anthropic principle Quantum gravity General relativity Quantum mechanics Lee Smolin Fine-tuned universe References External links Cosmological Natural Selection— Underscores the coincidence of the constants being tuned for biological life as well as for black holes. Challenges the notion of "coincidence" in this context. Scientific Alternatives to the Anthropic Principle Cosmic natural selection - Leonard Susskind's criticism