Anthropic principle
The anthropic principle, also known as the "observation selection effect",
There are many different formulations of the anthropic principle. Philosopher
Definition and basis
The principle was formulated as a response to a series of observations that the laws of nature and parameters of the universe have values that are consistent with conditions for life as it is known rather than values that would not be consistent with life on Earth. The anthropic principle states that this is an a posteriori necessity, because if life were impossible, no living entity would be there to observe it, and thus it would not be known. That is, it must be possible to observe some universe, and hence, the laws and constants of any such universe must accommodate that possibility.
The term anthropic in "anthropic principle" has been argued[6] to be a misnomer.[note 1] While singling out the currently-observable kind of carbon-based life, none of the finely tuned phenomena require human life or some kind of carbon chauvinism.[7][8] Any form of life or any form of heavy atom, stone, star, or galaxy would do; nothing specifically human or anthropic is involved.[9]
The anthropic principle has given rise to some confusion and controversy, partly because the phrase has been applied to several distinct ideas. All versions of the principle have been accused of discouraging the search for a deeper physical understanding of the universe. The anthropic principle is often criticized for lacking falsifiability and therefore its critics may point out that the anthropic principle is a non-scientific concept, even though the weak anthropic principle, "conditions that are observed in the universe must allow the observer to exist",[10] is "easy" to support in mathematics and philosophy (i.e., it is a tautology or truism). However, building a substantive argument based on a tautological foundation is problematic. Stronger variants of the anthropic principle are not tautologies and thus make claims considered controversial by some and that are contingent upon empirical verification.[11][12]
Anthropic Observations
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In 1961,
Dicke later reasoned that the density of matter in the universe must be almost exactly the
The observed values of the
Origin
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The phrase "anthropic principle" first appeared in
Carter defined two forms of the anthropic principle, a "weak" one which referred only to anthropic selection of privileged spacetime locations in the universe, and a more controversial "strong" form that addressed the values of the fundamental constants of physics.
Roger Penrose explained the weak form as follows:
The argument can be used to explain why the conditions happen to be just right for the existence of (intelligent) life on the Earth at the present time. For if they were not just right, then we should not have found ourselves to be here now, but somewhere else, at some other appropriate time. This principle was used very effectively by Brandon Carter and
intelligent life around only at the particular time that the coincidence did hold!, chapter 10
One reason this is plausible is that there are many other places and times in which humans could have evolved. But when applying the strong principle, there is only one universe, with one set of fundamental parameters, so what exactly is the point being made? Carter offers two possibilities: First, humans can use their own existence to make "predictions" about the parameters. But second, "as a last resort", humans can convert these predictions into explanations by assuming that there is more than one universe, in fact a large and possibly infinite collection of universes, something that is now called the
Since Carter's 1973 paper, the term anthropic principle has been extended to cover a number of ideas that differ in important ways from his. Particular confusion was caused by the 1986 book The Anthropic Cosmological Principle by
Carter was not the first to invoke some form of the anthropic principle. In fact, the
Ludwig Boltzmann may have been one of the first in modern science to use anthropic reasoning. Prior to knowledge of the Big Bang Boltzmann's thermodynamic concepts painted a picture of a universe that had inexplicably low entropy. Boltzmann suggested several explanations, one of which relied on fluctuations that could produce pockets of low entropy or Boltzmann universes. While most of the universe is featureless in this model, to Boltzmann, it is unremarkable that humanity happens to inhabit a Boltzmann universe, as that is the only place where intelligent life could be.[25][26]
Variants
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Weak anthropic principle (WAP) (Carter): "... our location in the universe is necessarily privileged to the extent of being compatible with our existence as observers."[21] For Carter, "location" refers to our location in time as well as space.
Strong anthropic principle (SAP) (Carter): "[T]he universe (and hence the
The Latin tag ("I think, therefore the world is such [as it is]") makes it clear that "must" indicates a deduction from the fact of our existence; the statement is thus a truism
In their 1986 book, The anthropic cosmological principle,
Weak anthropic principle (WAP) (Barrow and Tipler): "The observed values of all physical and
Unlike Carter they restrict the principle to carbon-based life, rather than just "observers". A more important difference is that they apply the WAP to the fundamental physical constants, such as the fine-structure constant, the number of spacetime dimensions, and the cosmological constant
Strong anthropic principle (SAP) (Barrow and Tipler): "The Universe must have those properties which allow life to develop within it at some stage in its history."[30]
This looks very similar to Carter's SAP, but unlike the case with Carter's SAP, the "must" is an imperative, as shown by the following three possible elaborations of the SAP, each proposed by Barrow and Tipler:[31]
- "There exists one possible Universe 'designed' with the goal of generating and sustaining 'observers'."
- This can be seen as simply the classic laws of natureand their fundamental physical constants set to ensure that life emerges and evolves.
- This can be seen as simply the classic
- "Observers are necessary to bring the Universe into being."
- Barrow and Tipler believe that this is a valid conclusion from It from bit) and his Participatory anthropic principle (PAP) which is an interpretation of quantum mechanics associated with the ideas of John von Neumann and Eugene Wigner.
- Barrow and Tipler believe that this is a valid conclusion from
- "An ensemble of other different universes is necessary for the existence of our Universe."
- By contrast, Carter merely says that an ensemble of universes is necessary for the SAP to count as an explanation.
The
Many 'anthropic principles' are simply confused. Some, especially those drawing inspiration from Brandon Carter's seminal papers, are sound, but... they are too weak to do any real scientific work. In particular, I argue that existing methodology does not permit any observational consequences to be derived from contemporary cosmological theories, though these theories quite plainly can be and are being tested empirically by astronomers. What is needed to bridge this methodological gap is a more adequate formulation of how observation
selection effects are to be taken into account.— Anthropic bias, Introduction[33]
Analysing an observer's experience into a sequence of "observer-moments" helps avoid certain paradoxes; but the main ambiguity is the selection of the appropriate "reference class": for Carter's WAP this might correspond to all real or potential observer-moments in our universe; for the SAP, to all in the multiverse. Bostrom's mathematical development shows that choosing either too broad or too narrow a reference class leads to counter-intuitive results, but he is not able to prescribe an ideal choice.
According to
Playwright and novelist Michael Frayn describes a form of the strong anthropic principle in his 2006 book The Human Touch, which explores what he characterises as "the central oddity of the Universe":
It's this simple paradox. The Universe is very old and very large. Humankind, by comparison, is only a tiny disturbance in one small corner of it – and a very recent one. Yet the Universe is only very large and very old because we are here to say it is... And yet, of course, we all know perfectly well that it is what it is whether we are here or not.[36]
Character of anthropic reasoning
Carter chose to focus on a tautological aspect of his ideas, which has resulted in much confusion. In fact, anthropic reasoning interests scientists because of something that is only implicit in the above formal definitions, namely that humans should give serious consideration to there being other universes with different values of the "fundamental parameters"—that is, the dimensionless physical constants and initial conditions for the Big Bang. Carter and others have argued that life would not be possible in most such universes. In other words, the universe humans live in is fine tuned to permit life. Collins & Hawking (1973) characterized Carter's then-unpublished big idea as the postulate that "there is not one universe but a whole infinite ensemble of universes with all possible initial conditions".[37] If this is granted, the anthropic principle provides a plausible explanation for the fine tuning of our universe: the "typical" universe is not fine-tuned, but given enough universes, a small fraction will be capable of supporting intelligent life. Ours must be one of these, and so the observed fine tuning should be no cause for wonder.
Although philosophers have discussed related concepts for centuries, in the early 1970s the only genuine physical theory yielding a multiverse of sorts was the
The anthropic idea that fundamental parameters are selected from a multitude of different possibilities (each actual in some universe or other) contrasts with the traditional hope of physicists for a theory of everything having no free parameters. As Albert Einstein said: "What really interests me is whether God had any choice in the creation of the world." In 2002, some proponents of the leading candidate for a "theory of everything", string theory, proclaimed "the end of the anthropic principle"[39] since there would be no free parameters to select. In 2003, however, Leonard Susskind stated: "...it seems plausible that the landscape is unimaginably large and diverse. This is the behavior that gives credence to the anthropic principle."[40]
The modern form of a
- The absurd universe: Our universe just happens to be the way it is.
- The unique universe: There is a deep underlying unity in physics that necessitates the Universe being the way it is. A Theory of Everythingwill explain why the various features of the Universe must have exactly the values that have been recorded.
- The multiverse: Multiple universes exist, having all possible combinations of characteristics, and humans inevitably find themselves within a universe that allows us to exist.
- Intelligent design: A creator designed the Universe with the purpose of supporting complexity and the emergence of intelligence.
- The life principle: There is an underlying principle that constrains the Universe to evolve towards life and mind.
- The self-explaining universe: A closed explanatory or causal loop: "perhaps only universes with a capacity for consciousness can exist". This is Wheeler's participatory anthropic principle (PAP).
- The fake universe: Humans live inside a virtual reality simulation.
Omitted here is
Clearly each of these hypotheses resolve some aspects of the puzzle, while leaving others unanswered. Followers of Carter would admit only option 3 as an anthropic explanation, whereas 3 through 6 are covered by different versions of Barrow and Tipler's SAP (which would also include 7 if it is considered a variant of 4, as in Tipler 1994).
The anthropic principle, at least as Carter conceived it, can be applied on scales much smaller than the whole universe. For example, Carter (1983)
Observational evidence
No possible observational evidence bears on Carter's WAP, as it is merely advice to the scientist and asserts nothing debatable. The obvious test of Barrow's SAP, which says that the universe is "required" to support life, is to find evidence of life in universes other than ours. Any other universe is, by most definitions, unobservable (otherwise it would be included in our portion of this universe[undue weight? ]). Thus, in principle Barrow's SAP cannot be falsified by observing a universe in which an observer cannot exist.
Philosopher
- Physical theory will evolve so as to strengthen the hypothesis that early phase transitions occur probabilistically rather than deterministically, in which case there will be no deep physical reason for the values of fundamental constants;
- Various theories for generating multiple universes will prove robust;
- Evidence that the universe is fine tunedwill continue to accumulate;
- No life with a non-carbon chemistrywill be discovered;
- Mathematical studies of galaxy formation will confirm that it is sensitive to the rate of expansion of the universe.
Hogan[47] has emphasised that it would be very strange if all fundamental constants were strictly determined, since this would leave us with no ready explanation for apparent fine tuning. In fact, humans might have to resort to something akin to Barrow and Tipler's SAP: there would be no option for such a universe not to support life.
Probabilistic predictions of parameter values can be made given:
- a particular multiverse with a "measure", i.e. a well defined "density of universes" (so, for parameter X, one can calculate the prior probabilityP(X0) dX that X is in the range X0 < X < X0 + dX), and
- an estimate of the number of observers in each universe, N(X) (e.g., this might be taken as proportional to the number of stars in the universe).
The probability of observing value X is then proportional to N(X) P(X). A generic feature of an analysis of this nature is that the expected values of the fundamental physical constants should not be "over-tuned", i.e. if there is some perfectly tuned predicted value (e.g. zero), the observed value need be no closer to that predicted value than what is required to make life possible. The small but finite value of the cosmological constant can be regarded as a successful prediction in this sense.
One thing that would not count as evidence for the anthropic principle is evidence that the Earth or the
Applications of the principle
The nucleosynthesis of carbon-12
Fred Hoyle may have invoked anthropic reasoning to predict an astrophysical phenomenon. He is said to have reasoned, from the prevalence on Earth of life forms whose chemistry was based on carbon-12 nuclei, that there must be an undiscovered resonance in the carbon-12 nucleus facilitating its synthesis in stellar interiors via the triple-alpha process. He then calculated the energy of this undiscovered resonance to be 7.6 million electronvolts.[48][49] Willie Fowler's research group soon found this resonance, and its measured energy was close to Hoyle's prediction.
However, in 2010 Helge Kragh argued that Hoyle did not use anthropic reasoning in making his prediction, since he made his prediction in 1953 and anthropic reasoning did not come into prominence until 1980. He called this an "anthropic myth," saying that Hoyle and others made an after-the-fact connection between carbon and life decades after the discovery of the resonance.
An investigation of the historical circumstances of the prediction and its subsequent experimental confirmation shows that Hoyle and his contemporaries did not associate the level in the carbon nucleus with life at all.[50]
Cosmic inflation
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String theory
String theory predicts a large number of possible universes, called the "backgrounds" or "vacua". The set of these vacua is often called the "multiverse" or "anthropic landscape" or "string landscape". Leonard Susskind has argued that the existence of a large number of vacua puts anthropic reasoning on firm ground: only universes whose properties are such as to allow observers to exist are observed, while a possibly much larger set of universes lacking such properties go unnoticed.[40]
Zhi-Wei Wang and Samuel L. Braunstein proved that life's existence in the universe depends on various fundamental constants. It suggests that without a complete understanding of these constants, one might incorrectly perceive the universe as being intelligently designed for life. This perspective challenges the view that our universe is unique in its ability to support life.[56]
Dimensions of spacetime
There are two kinds of dimensions:
The implicit notion that the dimensionality of the universe is special is first attributed to
In 1920, Paul Ehrenfest showed that if there is only a single time dimension and more than three spatial dimensions, the orbit of a planet about its Sun cannot remain stable. The same is true of a star's orbit around the center of its galaxy.[60] Ehrenfest also showed that if there are an even number of spatial dimensions, then the different parts of a wave impulse will travel at different speeds. If there are spatial dimensions, where k is a positive whole number, then wave impulses become distorted. In 1922, Hermann Weyl claimed that Maxwell's theory of electromagnetism can be expressed in terms of an action only for a four-dimensional manifold.[61] Finally, Tangherlini showed in 1963 that when there are more than three spatial dimensions, electron orbitals around nuclei cannot be stable; electrons would either fall into the nucleus or disperse.[62]
Max Tegmark expands on the preceding argument in the following anthropic manner.[63] If T differs from 1, the behavior of physical systems could not be predicted reliably from knowledge of the relevant partial differential equations. In such a universe, intelligent life capable of manipulating technology could not emerge. Moreover, if T > 1, Tegmark maintains that protons and electrons would be unstable and could decay into particles having greater mass than themselves. (This is not a problem if the particles have a sufficiently low temperature.)[63] Lastly, if N < 3, gravitation of any kind becomes problematic, and the universe would probably be too simple to contain observers. For example, when N < 3, nerves cannot cross without intersecting.[63] Hence anthropic and other arguments rule out all cases except N = 3 and T = 1, which describes the world around us.
On the other hand, in view of creating
In 2019, James Scargill argued that complex life may be possible with two spatial dimensions. According to Scargill, a purely scalar theory of gravity may enable a local gravitational force, and 2D networks may be sufficient for complex neural networks.[65][66]
Metaphysical interpretations
Some of the metaphysical disputes and speculations include, for example, attempts to back
William Sims Bainbridge disagreed with de Chardin's optimism about a future Omega point at the end of history, arguing that logically, humans are trapped at the Omicron point, in the middle of the Greek alphabet rather than advancing to the end, because the universe does not need to have any characteristics that would support our further technical progress, if the anthropic principle merely requires it to be suitable for our evolution to this point.[69]
The anthropic cosmological principle
A thorough extant study of the anthropic principle is the book The anthropic cosmological principle by
The book begins with an extensive review of many topics in the
Seeing little sense in a principle requiring intelligent life to emerge while remaining indifferent to the possibility of its eventual extinction, Barrow and Tipler propose the
Barrow and Tipler submit that the FAP is both a valid physical statement and "closely connected with moral values". FAP places strong constraints on the structure of the universe, constraints developed further in Tipler's The Physics of Immortality.[72] One such constraint is that the universe must end in a Big Crunch, which seems unlikely in view of the tentative conclusions drawn since 1998 about dark energy, based on observations of very distant supernovas.
In his review[73] of Barrow and Tipler, Martin Gardner ridiculed the FAP by quoting the last two sentences of their book as defining a completely ridiculous anthropic principle (CRAP):
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 that it is logically possible to know. And this is the end.[74]
Reception and controversies
Carter has frequently regretted his own choice of the word "anthropic", because it conveys the misleading impression that the principle involves humans specifically, rather than intelligent observers in general.
A common criticism of Carter's SAP is that it is an easy deus ex machina that discourages searches for physical explanations. To quote Penrose again: "[I]t tends to be invoked by theorists whenever they do not have a good enough theory to explain the observed facts."[77]
Carter's SAP and Barrow and Tipler's WAP have been dismissed as truisms or trivial tautologies—that is, statements true solely by virtue of their logical form and not because a substantive claim is made and supported by observation of reality. As such, they are criticized as an elaborate way of saying, "If things were different, they would be different",[citation needed] which is a valid statement, but does not make a claim of some factual alternative over another.
Critics of the Barrow and Tipler SAP claim that it is neither testable nor falsifiable, and thus is not a scientific statement but rather a philosophical one. The same criticism has been leveled against the hypothesis of a multiverse, although some argue[78] that it does make falsifiable predictions. A modified version of this criticism is that humanity understands so little about the emergence of life, especially intelligent life, that it is effectively impossible to calculate the number of observers in each universe. Also, the prior distribution of universes as a function of the fundamental constants is easily modified to get any desired result.[79]
Many criticisms focus on versions of the strong anthropic principle, such as Barrow and Tipler's anthropic cosmological principle, which are teleological notions that tend to describe the existence of life as a necessary prerequisite for the observable constants of physics. Similarly, Stephen Jay Gould,[80][81] Michael Shermer,[82] and others claim that the stronger versions of the anthropic principle seem to reverse known causes and effects. Gould compared the claim that the universe is fine-tuned for the benefit of our kind of life to saying that sausages were made long and narrow so that they could fit into modern hotdog buns, or saying that ships had been invented to house barnacles.[citation needed] These critics cite the vast physical, fossil, genetic, and other biological evidence consistent with life having been fine-tuned through natural selection to adapt to the physical and geophysical environment in which life exists. Life appears to have adapted to the universe, and not vice versa.
Some applications of the anthropic principle have been criticized as an
Lee Smolin has offered a theory designed to improve on the lack of imagination that anthropic principles have been accused of. He puts forth his fecund universes theory, which assumes universes have "offspring" through the creation of black holes whose offspring universes have values of physical constants that depend on those of the mother universe.[86]
The philosophers of cosmology John Earman,[87] Ernan McMullin,[88] and Jesús Mosterín contend that "in its weak version, the anthropic principle is a mere tautology, which does not allow us to explain anything or to predict anything that we did not already know. In its strong version, it is a gratuitous speculation".[89] A further criticism by Mosterín concerns the flawed "anthropic" inference from the assumption of an infinity of worlds to the existence of one like ours:
The suggestion that an infinity of objects characterized by certain numbers or properties implies the existence among them of objects with any combination of those numbers or characteristics [...] is mistaken. An infinity does not imply at all that any arrangement is present or repeated. [...] The assumption that all possible worlds are realized in an infinite universe is equivalent to the assertion that any infinite set of numbers contains all numbers (or at least all Gödel numbers of the [defining] sequences), which is obviously false.
See also
- A Fórmula de Deus – Novel by José Rodrigues dos Santos (discussing the anthropic principle)
- Anthropocentrism – Belief that humans are the most important beings in existence
- Arthur Schopenhauer – German philosopher (1788–1860) (an immediate precursor of the idea)
- Big Bounce – Model for the origin of the universe
- Copernican principle – Principle that humans are not privileged observers of the universe
- Doomsday argument – Doomsday scenario on human births
- Fermi paradox – Lack of evidence that aliens exist
- Goldilocks principle – Analogy for optimal conditions
- Great Filter – Whatever prevents interstellar civilisations from arising from non-living matter
- Infinite monkey theorem – Counterintuitive result in probability
- Inverse gambler's fallacy – Formal fallacy of Bayesian inference
- Mathematical universe hypothesis – Cosmological theory
- Measure problem (cosmology) – Concept in cosmology
- Mediocrity principle – Philosophical concept
- Metaphysical naturalism – Philosophical worldview rejecting 'supernatural'
- Neocatastrophism – Hypothesis for lack of detected aliens
- Fine-tuned universe – Hypothesis about life in the universe
- Quark mass and congeniality to life – Costa Rican physicist (work of Alejandro Jenkins)
- Rare Earth hypothesis – Hypothesis that complex extraterrestrial life is improbable and extremely rare
- Sleeping Beauty problem – Mathematical problem
- Triple-alpha process – Nuclear fusion reaction chain converting helium to carbon
- Why there is anything at all – Metaphysical question
Notes
- ^ "anthropic" means "of or pertaining to mankind or humans".
- ^ Strictly speaking, the number of non-compact dimensions, see String theory.
- ^ This is because the law of gravitation (or any other inverse-square law) follows from the concept of flux and the proportional relationship of flux density and field strength. If N = 3, then 3-dimensional solid objects have surface areas proportional to the square of their size in any selected spatial dimension. In particular, a sphere of radius r has a surface area of 4πr2. More generally, in a space of N dimensions, the strength of the gravitational attraction between two bodies separated by a distance of r would be inversely proportional to rN−1.
Footnotes
- ^ Bostrom, Nick (2008). "Where are they? Why I hope the search for extraterrestrial life finds nothing" (PDF). Technology Review. 2008: 72–77. Archived (PDF) from the original on 2022-10-09.
- ^ Bostrom, Nick (9 February 2020). "Was the Universe made for us?". anthropic-principle.com.
The data we collect about the Universe is filtered not only by our instruments' limitations, but also by the precondition that somebody be there to 'have' the data yielded by the instruments (and to build the instruments in the first place).
- ^ James Schombert. "Anthropic principle". Department of Physics at University of Oregon. Archived from the original on 2012-04-28. Retrieved 2012-04-26.
- ^ a b "Forms of the anthropic principle". britannica.com. Retrieved 4 August 2022.
- ^ "What is the anthropic principle?". thoughtco.com. Retrieved 4 August 2022.
- ^ Mosterín J., (2005), Antropic explanations in Cosmology, in Hajek, Valdés & Westerstahl (eds.), Proceedings of the 12th international congress of logic, Methodology and philosophy of science; http://philsci-archive.pitt.edu/1658/"
- ISBN 9781615922802.
- ^ Bostrom 2002, p. 6
- ISSN 0004-8402.
- ^ anthropic principle. Merriam-Webster online dictionary.
- ^ "The strong anthropic principle and the final anthropic principle". Archived from the original on 2019-07-29. Retrieved 2011-08-03.
- ^ "On knowing, Sagan from Pale blue dot".
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- ^ "New scientist space blog: Physicists debate the nature of space-time - New scientist".
- ^ How many fundamental constants are there? John Baez, mathematical physicist. U. C. Riverside, April 22, 2011
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- ^ Couchman, D. (August 2010). "The strong nuclear force as an example of fine tuning for life". Focus. Retrieved 15 July 2019.
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- ^ .; republished online by Cambridge University Press (7 Feb 2017)
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- ^ a b Bostrom 2002.
- Bibcode:1983QJRAS..24..146B.
- ^ Barrow & Tipler's definitions are quoted verbatim at Genesis of Eden diversity encyclopedia.
- ^ Barrow and Tipler 1986: 16.
- ^ Barrow and Tipler 1986: 21.
- ^ Barrow and Tipler 1986: 22.
- Bibcode:1986LIACo..26..439L.
- ^ Bostrom, N. (2002), op. cit.
- arXiv:quant-ph/0011122.
- ^ Jürgen Schmidhuber, 2002, "The speed prior: A new simplicity measure yielding near-optimal computable predictions." Proceedings of 15th annual conference on computational learning theory (COLT 2002), Sydney, Australia, Lecture notes in artificial intelligence. Springer: 216–228.
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- doi:10.1086/151965.
- S2CID 41548734.
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- ^ Bibcode:2003dmci.confE..26S.
- ^ Sober, Elliott, 2005, "The design argument" in Mann, W. E., ed., The Blackwell guide to the philosophy of religion. Blackwell publishers. Archived September 3, 2011, at the Wayback Machine
- ISBN 1-59102-381-5
- ^ Ikeda, M. and Jefferys, W. (2006). Unpublished FAQ "The anthropic principle does not support supernaturalism."
- ^ Gardner, James N., 2005, "The physical constants as biosignature: An anthropic retrodiction of the selfish biocosm hypothesis," International journal of astrobiology.
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- ^ Leslie, J. (1986) op. cit.
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- ^ University of Birmingham Life, Bent chains and the anthropic principle Archived September 27, 2009, at the Wayback Machine
- .
- ^ Kragh, Helge (2010). "When is a prediction anthropic? Fred Hoyle and the 7.65 MeV carbon resonance". Retrieved 2 July 2019.
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- ^ Tegmark (1998) op. cit.
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- doi:10.1111/j.1468-0068.2007.00645.x. Archived from the original(PDF) on 2016-08-24. Retrieved 13 April 2018.
- ^ Leibniz, Gottfried (1880). "Discourse on metaphysics". Die philosophischen schriften von Gottfried Wilhelm Leibniz. Vol. 4. Weidmann. pp. 427–463. Retrieved 13 April 2018.
- .. Also see Ehrenfest, P. (1917) "In what way does it become manifest in the fundamental laws of physics that space has three dimensions?" Proceedings of the Amsterdam academy 20:200.
- ^ Weyl, H. (1922). Space, time, and matter. Dover reprint: 284.
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- ^ S2CID 15694111. Retrieved 2006-12-16.
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- ^ "Life could exist in a 2D universe (according to physics, anyway)". technologyreview.com. Retrieved 2021-06-16.
- ^ a b Johann. Dorschner. und. Ralph. Neuhäuser. Evolution. des. Kosmos. und. der. Punkt. omega, in Nikolaus Knoepffler, H. James Birx, Teilhard de Chardin, V&R unipress GmbH, 2005, p. 109 ff
- ^ Giberson, Karl. "Anthropic principle: A postmodern creation myth?". Journal of interdisciplinary studies. 9.1/2 (1997): 63–90.
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- ^ Hicks, L. E. (1883). A critique of design arguments. New York: Scribner's.
- ^ Barrow and Tipler 1986: 23
- ISBN 978-0-385-46798-8.
- ^ Gardner, M., "WAP, SAP, PAP, and FAP," The New York review of books 23, No. 8 (May 8, 1986): 22–25.
- ^ Barrow and Tipler 1986: 677
- ^ e.g. Carter (2004) op. cit.
- ^ e.g. message from Martin Rees presented at the Kavli-CERCA conference (see video in External links)
- ISBN 978-0-19-851973-7.
- ^ Are parallel universes unscientific nonsense? Insider tips for criticizing the multiverse Tegmark, Max. February 4, 2014.
- S2CID 27409290. See also this news story.
- ^ Gould, Stephen Jay (1998). "Clear thinking in the sciences". Lectures at Harvard University.
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- ISBN 978-0-8050-8121-3.
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- ISBN 978-1-57392-859-5.
- S2CID 14340180.
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- ^ Earman John (1987). "The SAP also rises: A critical examination of the anthropic principle". American Philosophical Quarterly. 24: 307–317.
- ^ McMullin, Ernan. (1994). "Fine-tuning the Universe?" In M. Shale & G. Shields (ed.), Science, technology, and religious ideas, Lanham: University Press of America.
- ^ Mosterín, Jesús. (2005). Op. cit.
References
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- Cirkovic, M. M. (2004). "The anthropic principle and the duration of the cosmological past". Astronomical and Astrophysical Transactions. 23 (6): 567–597. S2CID 6068309.
- Conway Morris, Simon (2003). Life's solution: Inevitable humans in a lonely Universe. Cambridge University Press.
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- ISBN 978-0-553-34614-5.
- Stenger, Victor J. (1999), "Anthropic design," The skeptical inquirer 23 (August 31, 1999): 40–43
- ISBN 1-904987-21-4.
- Taylor; Stuart Ross (1998). Destiny or chance: Our Solar System and its place in the cosmos. Cambridge University Press. ISBN 978-0-521-78521-1.
- S2CID 15694111. A simple anthropic argument for why there are 3 spatial and 1 temporal dimensions.
- S2CID 119283361.
- Walker, M. A. & Cirkovic, M. M. (2006). "Anthropic reasoning, naturalism and the contemporary design argument". International Studies in the Philosophy of Science. 20 (3): 285–307. S2CID 8804703. Shows that some of the common criticisms of anthropic principle based on its relationship with numerology or the theological design argument are wrong.
- Ward, P. D. & Brownlee, D. (2000). ISBN 978-0-387-98701-9.
- ISBN 978-0-8090-9523-0.
External links
- Nick Bostrom: web site devoted to the anthropic principle.
- Friederich, Simon. Fine-tuning, review article of the discussion about fine-tuning, highlighting the role of the anthropic principles.
- Gijsbers, Victor. (2000). Theistic anthropic principle refuted – Positive atheism magazine.
- Chown, Marcus, Anything Goes, New scientist, 6 June 1998. On Max Tegmark's work.
- Stephen Hawking, Steven Weinberg, Alexander Vilenkin, David Gross and Lawrence Krauss: Debate on anthropic reasoning Archived 2020-04-10 at the Wayback Machine Kavli-CERCA conference video archive.
- Sober, Elliott R. 2009, "Absence of evidence and evidence of absence – Evidential transitivity in connection with fossils, fishing, fine-tuning, and firing squads.[permanent dead link]" Philosophical Studies, 2009, 143: 63–90.
- "Anthropic coincidence" – The anthropic controversy as a segue to Lee Smolin's theory of cosmological natural selection.
- Leonard Susskind and Lee Smolin debate the anthropic principle.
- Debate among scientists on arxiv.org.
- Evolutionary probability and fine tuning
- Benevolent design and the anthropic principle at MathPages
- Critical review of "The privileged planet"
- The anthropic principle – a review.
- Berger, Daniel, 2002, "An impertinent résumé of the Anthropic cosmological principle. Archived 2016-03-04 at the Wayback Machine" A critique of Barrow & Tipler.
- Jürgen Schmidhuber: Papers on algorithmic theories of everything and the anthropic principle's lack of predictive power.
- Paul Davies: Cosmic jackpot – Interview about the anthropic principle (starts at 40 min), 15 May 2007.