The final anthropic principle (FAP) is defined by physicists John D. Barrow and Frank J. Tipler's 1986 book "The Anthropic Cosmological Principle" as a generalization of the strong anthropic principle and the weak anthropic principle as follows:

• Final anthropic principle (FAP): "Intelligent information-processing must come into existence in the Universe, and, once it comes into existence, it will never die out."

Barrow and Tipler state that, although the FAP is a purely physical statement, the "validity of the FAP is the physical precondition for moral values to arise and so to continue to exist in the Universe: no moral values of any sort can exist in a lifeless cosmology. Furthermore, the FAP seems to imply a melioristic cosmos [that is, is a tendency throughout nature toward improvement]".

The FAP does not imply stability of the proton: it is possible to process information using the quantum number and spin state of positronium atoms.

Barrow and Tipler make a "very tentative prediction" that the FAP appears to imply that the Universe is either flat or closed (and not open; see topology of the universe).

Arguments to justify the eventual extinction of life

Many scientists seem to have used the second law of thermodynamics to "prove" that life (defined by Barrow and Tipler to be information processing capability) must eventually die out. One fallacy in such proofs lies in the false assumption that the Universe remains at a constant temperature; many cosmologies specify that as the Universe gets older, it gets colder (and thus heat engines operate with increasing efficiency).

Barrow and Tipler consider such arguments and quote Pierre Duheim , who wrote in 1914:

• "The deduction [of the Heat Death from the Second Law of thermodymanics] is marred in more than one place by fallacies. First of all, it implicitly assumes the assimilation of the universe to a finite collection of bodies isolated in a space absolutely devoid of matter; and this assimilation exposes one to many doubts. One this assimilation is admitted, it is true that the entropy of the universe has to increase endlessly, but it does not impose any lower or upper limit on this entropy; nothing then would stop this magnitude varying from to as time itself varied from to ; then the allegedly demonstrated imposibilities regarding an eternal life for the universe would vanish"

Selected quotes which assume FAP

• "Were one to adopt a teleological view of Nature, one could go so far as to assert that matter has many of its properties today not because these properties are necessary for life today, but because these properties will be essential for the existence of life in the distant future" Barrow and Tipler, "The Anthropic Cosmological Principle", p674
• "We see that if life evolves in all of the many universes in a quantum cosmology, and if life continues to exist in all of these universes, then all of these universes, which include all possible histories among them, will approach the Omega Point. At the instant the Omega Point is reached, life will have gained control of all matter and forces not only in a single universe, but in all universes whose existence is logically possible; life will have spread into all spatial regions in all universes which could logically exist, and will have stored an infinite amount of information, including all bits of knowledge which it is logically possible to know. And this is the end". Ibid, p676