Fine-tuned Universe

When fine-tuning of the universe, the precise matching of the size of natural constants in the current physical theories is referred to in cosmology, which seems to be necessary to explain the physical state of the observable universe. It is disputed whether this feature is real fine-tuning, if this is necessary for the explanation of nature, or whether this is just a consequence of inadequate, incomplete theories. (: Anthropic coincidence dt) used in the English literature instead of " fine tuning " is often the term " Anthropic Coincidence".

• 2.1 doubts about the existence of a fine-tuning 2.1.1 more fundamental theory without fine-tuned constants
• 2.1.2 Ensemble hypothesis and Anthropic Principle
• 2.1.3 teleological and theological explanation 2.1.3.1 criticism and discourse of the teleological and theological explanation

Constants, which has been postulated for fine-tuning

For the following physical constants of a possible fine-tuning will be discussed:

Fine tuning of the rate of expansion

The expansion of the universe may on the one hand not be so weak that the universe will collapse after a few millions of years, on the other hand is not as strong or the distribution of matter not be so thin that the formation of suns and galaxies is prevented. In the original standard cosmological model, which is not today's inflation theory integrated, the expansion rate is determined solely by the mass density must therefore aligned at the beginning of the universe to the tiny factor of exactly the critical density so called, to the formation of solar systems and to allow galaxies. The inflation theory would make this fine-tuning unnecessary, but would be here again a fine tuning of the cosmological constant is necessary.

Fine-tuning of the cosmological constant

The cosmological constant was originally introduced by Albert Einstein in his General Theory of Relativity, since only these which, according to the common opinion of his time to science, stable universe enabled. Through the discovery of Edwin Hubble, that our universe is not stable, but expands, eliminated the need of a cosmological constant and Einstein is they have labeled "the greatest blunder of my life ".

Developed in the 1980s, inflation theory and the observation made in 1998 that accelerated our universe is expanding, have led to the development of explanatory models, which make the cosmological constant needed again. Inflation theory and the theory to explain the accelerated expansion, need a so-called dark energy, which as a vacuum energy - can be interpreted - caused by a nonzero cosmological constant. However, in this case, would the cosmological constant at the beginning of the universe just after the " inflationary epoch " may differ from zero, but at the same times smaller than its current value have been. This corresponds to an extremely tiny vacuum energy density. Even small deviations from this value would lead to these explanatory models, to the fact that our present universe would have a strongly curved space-time and that the stars and planets would not be possible.

Whether fine-tuning is necessary, is doubtful. Have been developed theories in which dark energy is no longer connected to a curved space-time, but by a scalar field - caused - also called quintessence. In these theories no cosmological constant is needed.

Fine-tuning of the masses of the proton and electron as well as strengths of electromagnetic force and strong nuclear force

Max Born was of the opinion that at approximately the same proton and neutron mass, the properties of all atomic and molecular systems are mainly determined by two parameters: the mass ratio of electron to proton, as well as the fine structure constant, which indicates the strength of the electromagnetic interaction. If the ratio of electron mass to proton mass plotted in a diagram of the fine structure constant, so you can specify by Max Tegmark a local region, outside of which no life is possible, which is similar to ours. For example, would be at too high a mass ratio can no stable molecular systems exist for large core fluctuations; in the case of too much fine structure constant might exist no stars. However, Tegmark does not rule out that there could be many local areas in parameter space where different kind of life was possible.

William H. Press and Alan Lightman ( born 1948 ) have expanded in 1983, the model of Max Born and showed that the essential properties of the macro- physical phenomena are determined by four variables: the mass of the electron, the proton mass, the strength of the electromagnetic force, and the strength the strong force. Victor J. Stenger comes through analysis and computer simulations, in which he - in contrast to Tegmark - all four of the nominated Press and Lightman constants can be varied simultaneously to the conclusion that much larger variations of the constants are allowed. Analyzes of a hundred universes in which he can fluctuate randomly in a range of ten orders of magnitude (1010 ) the constants that resulted in more than half of the cases to stars with a lifetime of more than a billion years. This could be so Stenger, probably hardly call it fine tuning.

Production of carbon

Nuclear energy levels of beryllium -8 are considered critical for the extent and speed of the nucleosynthesis of carbon-12 in the stars and thus for the formation of carbon-based life (see also three- alpha process). Fred Hoyle was 1954, later confirmed experimentally exact location of the nuclear energy levels of beryllium theoretically predicted. In many cases, the position of this level is claimed as finely tuned.

The positions of the energy levels are indeed no fundamental constants of nature, however, depend on these. A change in these levels can only either be accompanied by a change in the constants of nature or a change in the underlying physical theories. A change in the physical constants, as well as the theories, but does not change only the position of the nuclear energy levels of beryllium, but also many other properties of all elements; so maybe could arise towards carbon and other development sectors. Heinz Oberhummer succeeded together with Attila Csótó and Helmut Schlattl quantifiable statements derive it by the cosmological fine-tuning of the fundamental forces in the universe in the formation of carbon and oxygen in the three- alpha process has been studied in red giants.

, Fine-tuning ' of the dimensions

Mathematics could have any number of dimensions, a universe. However, complex structures appear only in more than two dimensions. In a universe with more than three spatial dimensions both atoms and planetary orbits are unstable. Assuming, however, that in a different kind of universe other laws of nature would be valid, stable planetary orbits could be possible in higher dimensional universes stable atoms or under other laws of motion. Basically, the dimensions should not be limited to a natural number. Mathematics would also fractal dimensions of universes represented; the assumption that life only in the - observable for us - four-dimensional space -time continuum is possible, could also be a result of the Anthropic Principle.

Proposed explanations

Doubts about the existence of a fine-tuning

It is often denied that a fine-tuning exists. Is it not this, then there would logically also no need for explanation. If it exists, it is unclear how this would ever be proved.

The considerations for possible universes are focused largely on how nature needs to have in order to qualify for carbon- based life - as it was able to develop in our planetary system - to generate ( carbon chauvinism ). When changing the constants of nature may no stars would arise which would be durable enough to allow for the evolution of carbon-based life. Or else it would be possibly formed no or too little carbon; may not even could arise atomic or stable structures. However, all stable structures and environments are not even known which come as an alternative for carbon and make a hospitable planetary environment in question for the given constants of nature. For example, it is discussed whether silicon-based life is possible, although silicon can not take as many connections as carbon. If you change the constants of nature, so may also change the properties of silicon and all other elements that might cause silicon or other item acquired properties, comparable to those of carbon. It can not be excluded that constant change entirely different non-nuclear (or not molecular ) stable structures are possible, which can form compounds in a variety of ways and thus be used as a basis for life in question. Also new, stable environments could be possible, which can provide space for the development of life as an alternative to a planetary environment.

It is therefore questionable to what extent a proof ability of a fine-tuning exists because eventually all possible universes can not be named, in which - could create life - under different conditions. Therefore, trying instead to appoint some special conditions for carbon- based life to formulate general assumptions, which are necessary for all forms of life. For example, the presence of Entropiegradienten is often regarded as such a basic requirement for all forms of life. Could certain constants show that even with a small variation of no more Entropiegradienten can exist in the universe - for example, if only homogeneous, diluted hydrogen gas could exist - would be a strong argument for an actual fine-tuning under the current standard theories. But this is so far not succeeded.

If the fine-tuning of current physical theories exists and is a generally accepted evidence would be presented for only a stronger justification for the existence of our universe would be satisfactory; a statement that excludes the necessity of a chance. All potential explanations are currently being divisible into three categories, whose transitions are fluid and not necessarily mutually exclusive:

More fundamental theory without fine-tuned constants

The current physical theories are not fundamental, but only approximations still to be developed, comprehensive physical theories. The apparent fine-tuning would then possibly only an artifact of the Unvollkommenkeit of the currently available theory building. The theories are incomplete and therefore must be fine-tuned in order to describe the life-friendly universe correctly. One can then interpret the high number of constants in the current theories as a kind of screw. It is expected that more fundamental theories will have either no or very few constants. The fine tuning of necessary at the moment constants of nature would, therefore, does indeed point to a creation, but not as a theological or teleological explanation than creation of the universe inherent by a Creator God or by a natural impulse, but quite banal as a result of the creation of a theory by natural science. One should then expect that these artifacts disappear when you have these fundamental, comprehensive theories found. Only when still fine-tuning would have existed, one could conclude that this is one of nature's inherent property. In the case of a fundamental theory without fine-tuning would then perhaps all or at least a large proportion of all possible universes have the necessary complexity for life and not just a vanishingly small proportion as in the case of an existing fine-tuning. As a candidate for such a basic theory, among others, the superstring theory is traded.

Ensemble hypothesis and Anthropic Principle

A random fine-tuning is usually considered to be associated with a high improbability. Contrast, argued the anthropic principle that only those universes or parts of it are observable in which we can exist; that is, a statistical independence between our existence and observation of fine-tuning as a condition of statistical reasoning is not available. Statements about the probability or improbability of the fine-tuning can therefore not be made or only with additional assumptions. An often represented additional assumption, which could offer together with the anthropic principle, a statement is the hypothesis of a multiverse: Instead of a single universe, there are many or even an infinite number of parallel universes, with different physical properties. Our universe would be only one of many - one in which enable the proper conditions of life. It is discussed whether a multiverse itself would also have finely tuned physical constants, so this would only mean a shift of the question; the philosopher Nick Bostrom, however, denies this.

A similar explanation would postulate a sufficiently large single universe in which unobservable parts have different physical properties.

Teleological and theological explanation

Proponents of this hypothesis assume that the universe is aligned either by a teleological principle or by a conscious, intelligent being, such as a god in the theological sense, to a specific goal in mind and that the universe is why having life-friendly conditions. There is a purposeful sense, possibly due to the limitations of the human mind, this is not disclosing. Will be represented this hypothesis, for example, by the religious philosopher Richard Swinburne.

Criticism and discourse of the teleological and theological explanation

The term "fine tuning" is criticized: it was not a scientific term, but come from the engineering sciences and is misleading because of its teleological connotation. In addition to the objections which concern the validity of teleological hypotheses within scientific explanations in general, there are objections which reverse the arguments of Teleologiebefürworter. By way of example:

• In the opinion of E. Sober, and M. Ikeda and Jefferys as the adoption of an otherwise unspecified Creator is no explanation for the fine-tuning, as this Creator, who is powerful enough to create universes, creating life in a finely tuned universe could not. Even if would have the right size in a universe not of those considered fine-tuned constants, it would be for him certainly possible to provide in this otherwise hostile universe at a local place for conditions that would allow life. For example, if the interaction constants of the forces would not have the correct size, so that carbon-12 could not arise in a natural way, so could an all-powerful creator can arise through supernatural intervention still the life necessary for carbon-12. If the universe were created by a Creator, there would on this view, no reason to expect a fine-tuned universe, and therefore provides the teleological hypothesis no explanation for fine-tuning of the universe.

• For M. Ikeda and B. Jefferys this argument is a powerful confirmation of naturalism, namely the assumption that in our universe everything is done with the "right things", so according to the law and without supernatural intervention. They argue that precisely the hypothetical observation that the universe not only is not fine-tuned, but would indeed be downright unsuitable for life, would point to a Creator. After all, only under the condition that our universe behave strictly according to law, there is the need for fine-tuning and accounted for the need divine intervention and creative impulses. However, quite well, it is argued that a possible creative power from the beginning to the laws of nature has created such that allow this life. The rational intelligibility of the universe is thus interpreted as an indication of the existence of a creative force. Proponents of that view, for example, the mathematician and philosopher John Lennox or the geneticist Francis Collins.

• Both the argument Richard Swinburne, as well as the argument of M. Ikeda and B. Jefferys to use their reasoning Bayesian statistics, which is not universally accepted and is rejected, for example, by representatives of an objective probability term. Even among supporters of Bayesian statistics, there is no consensus on what kind of hypotheses Bayesian statistics can be applied. One of the most famous representatives of the Bayesian statistics, B. de Finetti, limits the applicability of Bayesian statistics, for example, to such statistical hypotheses which are ultimately empirically decidable.

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