On the Cosmic Uroboros, as I call it, if the mouth swallowing the tail is drawn at the top, humans at one meter or so fall more or less at the bottom-i. Many students are so stunned by this apparently special place that they refuse to believe it and insist it must be a result of some tricky choice of units.
I don't know if the center of the Cosmic Uroboros is in fact special, but finding themselves there certainly strikes a chord with most people. Perhaps it hearkens back to the soul-satisfying cosmology of the Middle Ages, where earth was truly the center of the universe. At different scales, different laws of physics tend to control events.
The Cosmic Uroboros thus becomes not only a way of realizing that the universe exists on all scales but also a map of emergent properties, with new properties appearing as you move a few orders of magnitude in either direction along the body of the serpent.
What the Uroboros does not represent is evolution. Modern cosmology will never be fully represented by a single idea. It contains several ideas that are each powerful enough to change people's thinking, if they can be communicated. Another example is Cosmic Inflation, which, of course, may or may not be true, but is the best explanation we have today for the initial conditions that led to the Big Bang and the relatively slow but stable expansion of the universe that has followed.
In the tradition of "as above, so below," here is a suggestion [10] of how present-day issues could be seen in a new way through the metaphor of Cosmic Inflation. It is well known that modern technological nations are addicted to overconsumption at the expense of poorer peoples and the global environment, yet our nations seem powerless to change course. While the global population increased about four-fold from to , energy use increased by nearly two orders of magnitude.
We have been told by experts for decades that the human species is heading for disaster on a potentially monstrous scale unless we change our ways, but most of us remain addicted to consumerism. The single most important question of this generation may be, how can global civilization make the transition gracefully from inflationary consumption to a sustainable level?
No answer has been be found in normal political processes. I think it was Einstein who said that no fundamental problem is ever solved at the same level at which it is posed. On what level then might a solution be found? Mathematically meaningful patterns of the universe-for example, the transition from cosmic inflation to expansion-may exist on a human scale too. Applying them to large-scale human problems could burst us out of the narrow perspective within which these problems have seemed intractable.
This narrow perspective justifies its failures with a trendy cynicism that threatens to doom us. In the larger perspective may lie Einstein's kind of solution. In "Cosmology and Culture," our course at the University of California, Santa Cruz, Nancy Abrams and I trace the effects of the major changes in cosmology in the cultures that were the soil and roots of our own. In alternate weeks, more or less, we look at the universe-pictures of the Ancient Middle East and Greece, of Medieval Christian and Jewish Kabbalistic Europe, of the Enlightenment cosmology of Newton, and of the global consumer world culture of today.
In alternate weeks we introduce the fundamental elements of the expanding universe picture. We encourage students to think about how the emerging scientific cosmology may change their own worldviews. Probably more than any particular knowledge or material goods, our society needs inspiration. This may be the only thing capable of drastically changing enough minds so that the human species does not, in Einstein's phrase, "drift toward unparalled catastrophes.
In this way, practicing science has a spiritual goal. In fact, it can be itself a spiritual practice. It is often said that science is the religion of the modern world.
This may be true for many members of the modern world who see only the impressive results of science and do not understand the processes by which these results come to be. Worship is always possible in the face of mystery. But science is not a religion for a research scientist like me.
Without attempting to define religion, I will say that for me, science as a spiritual practice involves no dogmas or creeds, no human authority, no sacred text, and no divine being. There are aspects of science that involve all these factors except the last, but they are not the spiritual aspects.
Rigorous honesty. I am scrupulous with others about my data, logic, procedures. In some sense, when I venture into predictions of how the universe will one day be found to behave, I am representing humanity, and that is a moral obligation I take seriously but with elation. The more difficult but equally crucial form of honesty is with myself, regarding the limitations of my, or anyone's, knowledge. Humility is an essential ingredient in honesty.
I am always humble before the data, aware that theorists like myself can at best suggest interesting hypotheses and determine what conclusions follow from given hypotheses, while only observations can tell which hypotheses might be true.
Give credit where credit is due. My place in the universe is largely a place in other people's minds, and I want it to be accurate. By the same token, the role of each of my competitors and collaborators is a fact of nature, and to misrepresent that is an insult to the idea of science.
At a spiritual level, gratitude is fundamentally a giving of credit where credit is due. Nature does not reveal her secrets easily, and to value those secrets requires a long-term commitment. It takes many years of schooling and constant study of the literature in one's field, not to mention teaching and service, to be able to continue research long enough and get enough support to penetrate even the smallest aspect of nature successfully.
In sum, one approach to anthropic reasoning aims to clarify the rules of reasoning applicable to predictions made by observers in a large or infinite universe. This line of work is motivated by the idea that without such principles we face a severe skeptical predicament, as observations would not have any bearing on the theory. Yet there is still not general agreement on the new principles required to handle these cases, which are of course not scientifically testable principles: they are philosophically based proposals.
According to an alternative approach, selection effects can and should be treated within the context of a Bayesian approach to inductive inference see Neal ; Trotta There is much further work to be done in clarifying and assessing these and other approaches to anthropic reasoning.
Fine-tuning arguments start from a conflict between two different perspectives on certain features of cosmology or other physical theories. On the first perspective, the existence of creatures like us seems to be sensitive to a wide variety of aspects of cosmology and physics.
To be more specific, the prospects for life depend sensitively on the values of the various fundamental constants that appear in these theories. The SM includes about 10 constants, and the particle physics standard model includes about 20 more.
Yet it does seem plausible that intelligence requires an organism with complex structural features, living in a sufficiently stable environment. At a bare minimum, the existence of life seems to require the existence of complex structures at a variety of scales, ranging from galaxies to planetary systems to macro-molecules. Such complexity is extremely sensitive to the values of the fundamental constants of nature. From this perspective, the existence of life in the universe is fragile in the sense that it depends sensitively on these aspects of the underlying theory.
This view contrasts sharply with the status of the constants from the perspective of fundamental physics. Particle physicists typically regard their theories as effective field theories, which suffice for describing interactions at some specified energy scale. These theories include various constants, characterizing the relative strength of the interactions they describe, that cannot be further explained by the effective field theory.
The constants can be fixed by experimental results, but are not derivable from fundamental physical principles. If the effective field theory can be derived from a more fundamental theory, the value of the constants can in principle be determined by integrating out higher-energy degrees of freedom.
But this merely pushes the question back one step: the constants appearing in the more fundamental theory are determined experimentally. Similarly, the constants appearing in the SM are treated as contingent features of the universe. There is no underlying physical principle that sets, for example, the cosmological densities of different kinds of matter, or the value of the Hubble constant.
So features of our theories that appear entirely contingent, from the point of view of physics, are necessary to account for the complexity of the observed universe and the very possibility of life. The unease develops into serious discomfort if the specific values of the constants are taken to be extremely unlikely: how could the values of all these constants be just right , by sheer coincidence?
In many familiar cases, our past experience is a good guide to when an apparent coincidence calls for further explanation.
As Hume emphasized, however, intuitive assessments from everyday life of whether a given event is likely, or requires a further explanation, do not extend to cosmology. Recent formulations of fine-tuning arguments often introduce probabilistic considerations. Introducing a well-defined probability over the constants would provide a response to Hume: rather than extrapolating our intuitions, we would be drawing on the formal machinery of our physical theories to identify fine-tuning.
Promising though this line of argument may be, there is not an obvious way to define physical probabilities over the values of different constants, or over other features of the laws. There is nothing like the structure used to justify physical probabilities in other contexts, such as equilibrium statistical mechanics.
The multiverse response replaces a single, apparently finely-tuned universe within an ensemble of universes, combined with an appeal to anthropic selection. Suppose that all possible values of the fundamental constants are realized in individual elements of the ensemble. Many of these universes will be inhospitable to life. In calculating the probabilities that we observe specific values of the fundamental constants, we need only consider the subset of universe compatible with the existence of complexity or some more specific feature associated with life.
If we have some way of assigning probabilities over the ensemble, we could then calculate the probability associated with our measured values. These calculations will resolve the fine-tuning puzzles if they show that we observe typical values for a complex or life-permitting universe.
Many cosmologists have argued in favor of a specific version of the multiverse called eternal inflation EI. On this line of thought, the multiverse should be accepted for the same reason we accept many claims about what we cannot directly observe—namely, as an inevitable consequence of an established physical theory.
It is not clear, however, that EI is inevitable, as not all inflationary models, arguably including those favored by CMB observations, have the kind of potential that leads to EI. There have been two distinct approaches to recovering some empirical content in this situation.
Detection of a distinctive signature that cannot be explained by other means would provide evidence for the multiverse. However, there is no expectation that a multiverse theory would generically predict such traces; for example, if the collision occurs too early the imprint is erased by subsequent inflationary expansion.
The process of forming the pocket universes is assumed to yield variation in the local, low-energy physics in each pocket. The aim is to obtain probabilistic predictions for what a typical observer should see in the EI multiverse.
Yet there are several challenges to overcome, alongside those mentioned above related to anthropics. The assumption that the formation of pocket universes leads to variation in constants is just an assumption, which is not yet justified by a plausible, well-tested dynamical theory.
It is difficult to define a measure because the EI multiverse is usually taken to be an infinite ensemble, lacking in the kinds of structure used in constructing a measure. On our view, these unmet challenges undercut the hope that the EI multiverse yields probabilistic predictions. And without such an account, the multiverse proposal does not have any testable consequences. If everything happens somewhere in the ensemble, then any potential observation is compatible with the theory.
Supposing that we grant a successful resolution of all these challenges, the merits of a multiverse solution of fine-tuning problems could then be evaluated by comparison with competing ideas. Claims that we occupy one of infinitely many possible pocket universes, filled with an infinity of other observers, rest on an enormous and speculative extrapolation. Such claims fail to take seriously the concept of infinity, which is not merely a large number.
Hilbert [] emphasized that while infinity is required to complete mathematics, it does not occur anywhere in the accessible physical universe. One response is to require that infinities in cosmology should have a restricted use. It may be useful to introduce infinity as part of an explanatory account of some aspect of cosmology, as is common practice in mathematical models that introduce various idealizations. Yet this infinity should be eliminable, such that the explanation of the phenomena remains valid when the idealization is removed.
In sum, interest in the multiverse stems primarily from speculations about the consequences of inflation for the global structure of the universe. As mentioned at the start, the uniqueness of the universe raises specific problems as regards cosmology as a science. First we consider issues to do with verification of cosmological models, and then make a comment as regards interpreting the human implications of cosmology. The basic challenge in cosmology regards how to test and evaluate cosmological models, given our limited access to the unique universe.
As discussed above, current cosmological models rely in part on extrapolations of well-tested local physics along with novel proposals, such as the inflaton field. Distinctions that are routinely employed in other areas of physics, such as that between laws and initial conditions, or chance and necessity, are not directly applicable, due to the uniqueness of the universe.
Recent debates regarding the legitimacy of different lines of research in cosmology reflect different responses to this challenge. One response is to retreat to hypothetico-deductivism HD : a hypothesis receives an incremental boost in confidence when one of its consequences is verified and a decrease if it is falsified. A second response is that the challenge requires a more sophisticated methodology.
This may take the form of acknowledging explicitly the criteria that scientists use to assess desirability of scientific theories Ellis , which include considerations of explanatory power, consistency with other theories, and other factors, in addition to compatibility with the evidence.
These come into conflict in unexpected ways in cosmology, and these different factors should be clearly articulated and weighed against one another. Alternatively, one might try to show that some of these desirable features, such as the ability to unify diverse phenomena, should be taken as part of what constitutes empirical success. Finally, a key issue is what scope do we expect our theories to have.
Ellis makes a distinction between Cosmology , which is the physically based subject dealt with in the textbooks listed in this article, dealing with the expansion of the universe, galaxies, number counts, background radiation, and so on, and Cosmologia , where one takes all that as given but adds in consideration about the meaning this all has for life.
Clearly the anthropic discussions mentioned above are a middle ground. We will make just one remark about this here. If one is going to consider Cosmologia seriously, it is incumbent on one to take seriously the full range of data appropriate to that enterprise. That is, the data needed for the attempted scope of such a theory must include data to do with the meaning of life as well as data derived from telescopes, laboratory experiments, and particle colliders.
It must thus include data about good and evil, life and death, fear and hope, love and pain, writings from the great philosophers and writers and artists who have lived in human history and pondered the meaning of life on the basis of their life experiences. This is all of great meaning to those who live on Earth and hence in the Universe.
To produce books saying that science proves there is no purpose in the universe is pure myopia. It just means that one has shut ones eyes to all the data that relates to purpose and meaning; and that one supposes that the only science is physics for psychology and biology are full of purpose.
Work on this entry was supported by a grant from the John Templeton Foundation. The statements made here are those of the authors and are not necessarily endorsed by the Foundation. Philosophy of Cosmology First published Tue Sep 26, The second is Cosmology deals with the physical situation that is the context in the large for human existence: the universe has such a nature that our life is possible.
Global Interplay in Cosmology 2. Underdetermination 2. Origins of the Universe 3. Anthropic Reasoning and Multiverse 4. Testing models 5. There are several distinctive epochs in the history of the universe, according to the SM, including the following: Quantum gravity : Classical general relativity is expected to fail at early times, when quantum effects will be crucial in describing the gravitational degrees of freedom.
There is considerable uncertainty regarding physics at this scale. The predicted light-element abundances depend on physical features of the universe at this time, such as the total density of baryonic matter and the baryon to photon ratio.
Agreement between theory and observation for a specific baryon to photon ratio Steigman is a great success of the SM. Dark Ages : After decoupling, baryonic matter consists almost entirely of neutral hydrogen and helium. Once the first generation of stars form, the dark ages come to an end with light from the stars, which re-ionizes the universe. Structure Formation : Cold dark matter dominates the early stages of the formation of structure. Dark matter halos provide the scaffolding for hierarchical structure formation.
The first generation of stars aggregate into galaxies, and galaxies into clusters. Massive stars end their lives in supernova explosions and spread through space heavy elements that have been created in their interiors, enabling formation of second generation stars surrounded by planets. Dark Energy Domination : Dark energy or a non-zero cosmological constant eventually comes to dominate the expansion of the universe, leading to accelerated expansion.
Global Interplay in Cosmology Although cosmology is generally seen as fitting into the general physics paradigm of everything being determined in a bottom up manner, as in the discussion above, there is another tradition that sees the effect of the global on the local in cosmology.
This has to be due to special initial conditions at the start of the universe Ellis It is because of this effect that studies of structure such as the BAO and CMB anisotropies give us strong limits on the parameters of the background model Ade et al. Underdetermination Many philosophers hold that evidence is not sufficient to determine which scientific theory we should choose.
This question arises in several concrete cases: Existence of low CMB anisotropy power at high and angular scales relative to that predicted by the SM Schwarz et al.
Origins of the Universe Cosmology confronts a distinctive challenge in accounting for the origin of the universe. Projecting observed features of the universe backwards leads to an initial state with three puzzling features: [ 35 ] Uniformity : The FLRW models have a finite particle horizon distance, much smaller than the scales at which we observe the CMB. It is challenging to explain both properties dynamically. In the standard FLRW models, the perturbations have to be coherent on scales much larger than the Hubble radius at early times.
One form of this response challenges appeals to probability, undermining the claim that there are unexplained coincidences. Alternatively, fine-tuning is taken to reveal that the laws alone are not sufficient to account for some features of nature; these features are properly explained by the laws in conjunction with various contingent facts.
Designer : Newton famously argued, for example, that the stability of the solar system provides evidence of providential design. For the hypothesized Designer to be supported by fine-tuning evidence, we require some way of specifying what kind of universe the Designer is likely to create; only such a specific Design hypothesis, based in some theory of the nature of the Designer, can offer an explanation of fine-tuning. In this sense, cosmology is one of the earliest fields that yielded evidence that was in conflict with the traditional religious worldview.
In fact, every advance in cosmology has seemed to fly in the face of the most cherished assumptions that we'd like to make about how special humanity is as a species This passage from The Grand Design by Stephen Hawking and Leonard Mlodinow eloquently lays out the transformation in thinking that has come from cosmology:.
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Math and Physics Expert. Andrew Zimmerman Jones is a science writer, educator, and researcher. He is the co-author of "String Theory for Dummies. Updated April 08, Featured Video. Cite this Article Format. By collecting and analysing data on human behaviour, Comte concluded, the same laws that controlled the wider universe should be discovered in human affairs. There have been a few attempts, for example, to identify Einsteinian relativity either as a form of political discourse, or to draw political implications from it.
As far as the former is concerned, I refer to the French feminist and social theorist Luce Irigaray who has identified the theory of relativity as a political rather than scientific formula [ 29 ]. Sokal and Bricmont [ 28 ], meanwhile, noted how the notion of relativity in time and space was used by postmodern theorists in order to advocate cultural relativity on the grounds that, if the universe has no single centre, neither does culture.
The consequences of Newtonianism the belief that the entire universe is mathematically regulated permeate western thought wherever there has been a search for a universal law based on supposedly hard data.
Psychology is a prime example. The measurement and mathematical analysis of the human mind then became the basis of much psychiatry and academic psychology. Jung opened a radically different strand of thought in modern psychology which is highly influential in many schools of psychotherapy and counselling practiced in society as a whole, although usually outside the academic system.
Jung revived the Platonic theory that everything in the world is a manifestation of an original pure idea or archetype. The idea that one can become one who truly is also relates back to Aristotelian cosmology in which it was thought that the four elements fire, earth, air and water all try to find their natural place in the world. This, Aristotle thought, was why flames go up to the sky, where fire belongs, and water falls to the ground, because that is where it finds its natural home.
In Aristotelian politics, kings are at the top of society and peasants at the bottom, because that is the natural state of affairs; in Aristotelian psychology every individual then has a natural way of being.
Jung, though, was equally concerned with the latest science, and formed a collaboration and friendship with the quantum physicist Wolfgang Pauli — [ 35 ]. Together they formulated the concept of synchronicity by which meaningful events are connected because they take place at the same time, without any causal connection [ 36 ]. Newtonian psychology—the belief that all mental states can be measured—survives in university departments and psychiatry.
Like Dante, Godwin used his story to describe the structure of the cosmos, now, after Johannes Kepler and Galileo, rejecting the planetary spheres and challenging the Aristotelian idea that all things have their natural place. Godwin departed from the old idea of a journey of the soul or a dream world.
Instead, his hero, Gonzales, flies to the Moon carried by giant geese. While celestial journey films can be enjoyed as simple adventures, they often contain deeper meanings. Released at a time when the Cold War was reaching its height with the conflict in Korea, the story featured a wise alien who arrived from space in order to reveal to humanity the error of its ways. Cosmology, through film, then becomes a means of commenting on societal change.
It is set in a utopian future in which there is one world government, collaborating with other worlds through United Federation of Planets, and money has been abolished. The values espoused by the Federation were American: freedom from tyranny, freedom of expression and respect for minorities.
In all such cases the cosmos is seen as a blank slate, a tabula rasa, on which human concerns are imposed. There is a constant strand of literary comment on cosmology in the nineteenth century. Poe realised that in a Newtonian universe the stars are likely to collapse in on each other, and that therefore the universe must be evolving [ 42 ]. For Hardy evolution was a reality.
His portrayal of Galileo as the heroic intellectual defending Copernicus, struggling against an obscurantist Inquisition inaccurate because many in the senior Catholic hierarchy were Copernicans , was an allegory of the revolutionary struggles of the s. This hypothetical particle, the tachyon, might as Martin Rees [ 46 ], says alter the order of events, if a signal from a tachyon arrived before it was sent.
The Doctor himself is increasingly represented as a lonely figure, destined to exist in perpetual sadness caused by the death or departure of his companions. Raindrops hang motionless in air. The concept that all time exists simultaneously actually has a long lineage.
Augustine V. Elliot, impressed by Einstein, combined the lessons of relativity with Plato, Ecclesiastes and Augustine.
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