Cosmology and our View of the World
Scientific Revolutions or Steps in an Evolution? Lead: Willie Roda
Summary by Joseph Collins
Scientific Revolutions or Steps in an Evolution?
Reading: Primack & Abrams, The View from the Center of the Universe, Chapters 2 & 3
The purpose of this class session was to examine the links between historical cosmologies and contemporary cosmology (i.e., “the new scientific picture of the universe”). This entails both anthropology (to understand the worldviews of past cultures) as well as astronomy/astrophysics (to understand the physical origin/nature of our universe).
Our (Western) understanding of cosmology has changed greatly since the dawn of civilization. Some of these changes consisted of newer cosmologies piggy-backing on older ones (e.g., the Hebrews adapting Babylonian astronomy to monotheism). However, this historical development has also been marked by radical changes—scientific revolutions—when established theories are abandoned in favor of new and different ideas. The best example of this phenomenon is the “Copernican Revolution,” when the prevailing geocentric picture of the cosmos was replaced by a heliocentric model. Another example is the leap from thinking of the earth as flat (so the ancient Egyptians and Israelites) to envisioning a spherical cosmos. Einstein’s alterations to Newtonian mechanics were also discussed as an example of scientific change. This led Prof. Möbius to comment that there are limits to understanding this as a revolution since Newton’s laws are still largely applicable (at least on a human scale).
The mutability of cosmological theories over time leads to the question: what is the truth behind any of them? In many religious viewpoints, truth is typically seen as something beyond question. To modern science, truth is always open to question—theories only last until they are disproved. Ultimate truth (i.e. Truth) is considered to be unchanging and eternal. However, we should not assume that the universe has to make sense to us humans (e.g., while we might not presently know just what dark matter is that alone does not mean that it does not exist). As Prof. Möbius points out, we can ask just as easily why the universe should make sense to us humans at all.
Several historical cosmologies were then examined, beginning with the ancient Egyptians. Based upon observation of their world, ancient Egyptian cosmology nurtures “the experience of being” an integral part of the cosmos (in contrast to the Newtonian model). Human beings were charged with preserving and upholding the sacred order of the universe (Ma’at) in partnership with their gods (especially the Pharaoh). The Egyptians did not have a single creation narrative, but several. In one, Nut (the heavens) is split apart from Geb (the earth) by their father Shu (space)—see Figure 1.1 in the link (from: http://ablemedia.com/ctcweb/images/egyptnut.gif). According to another account, the world began with a primeval mound that emerged from the watery chaos. This latter picture is reminiscent of the annual inundation of the Nile valley upon which Egyptian agriculture (and, by extension, society) depended.
The variety of creation accounts suggests that Egyptian cosmology was open to interpretation, encouraging speculation and the recombination of old and new ideas. This openness/flexibility is believed by Primack & Abrams to account (at least partially) for the tremendous longevity of ancient Egyptian beliefs (ca. 3000 years). This stability was questioned, with it being pointed out that technological change (e.g., in the areas of mummification and tomb construction) led to significant alterations to Egyptian beliefs. [It is also my opinion that Primack & Abrams grossly underrepresented the importance of the afterlife to Egyptian cosmology. Such beliefs were absolutely central for the ancient Egyptians—consider the vast amounts of economic resources dedicated to mummification, tomb building, funerary temples, etc. It should also be noted that Egyptian beliefs about the afterlife were speculative and, with the exception of the preservation of remains buried in the desert, hardly the result of careful observation of their physical environment. –JC]
The next cosmology to be discussed was that of the Hebrew Bible (Tanakh). Their ideas seem to have been largely borrowed from the ancient Babylonians. However, these were adapted by the Hebrews to fit with their distinctive concept of the One God. The most famous example of biblical cosmology is the creation account in the first chapter of the Book of Genesis—see Figure 1.2 in the link (http://biblicalstudies.qldwide.net.au/cs-1-6creation.jpg) —although cosmological ideas can be found throughout the Hebrew Bible (particularly the Psalms and the Book of Job). From these texts, it appears that the Hebrews believed that the earth (i.e., dry land) was flat. Both above and below this earth was watery chaos. A solid dome, or firmament, which contained the celestial bodies and held back the waters above, was thought to arch over the sky.
Next the cosmological views of the ancient Greeks were explored. Rather than studying the beliefs of a broader culture as previously, emphasis was put on the contributions of individual thinkers. The first of these to be covered was Thales of Miletus. Although none of his writings have survived, he was credited by Aristotle as having “invented the founding idea of science: that the seemingly infinite complexity of the world can be explained by means of a small number of hypotheses.” He also proposed the first theory of matter, that “there is a substance from which everything is made, and the substance is conserved; it is not created and cannot be destroyed” (59). This substance was, according to Thales, water. The class discussed the reason for this, with water’s necessity for life, multiple states, as well as a holdover from mythology and the physical geography of the Greek world being proposed. What was particularly revolutionary about Thales’ ideas was that they limited the powers of the gods, making it possible to seek mechanistic (rather than divine) explanations for physical phenomena.
Thales’ ideas marked the beginning of the ancient Greeks’ attempt to rationalize nature by seeking to understand it logically. Anaximander, a student of Thales, believed “that everything in nature had an inherent character, which made it what it was.” This character, which he called “physis” was “incorruptible, immortal, and eternal” and represents the origin of “physics” (60).
Pythagoras broke with the previously accepted idea of a flat earth. He “proposed
that the earth, sun, moon, and planets all turned around a central fire, and
their distances from the fire corresponded to the intervals of notes on a musical
scale.” Primack & Abrams identify this breakthrough as the beginning
of cosmology, which itself is a Greek word meaning “reasoning about the
cosmos.” Although used by us to refer to the universe, “cosmos”
originally signified “a crafted, composed, beauty-enhancing order.”
The goal of the Greek cosmology, then, became to explain this order in a way
that was “consistent with astronomical observations and based on mathematics”
(61). However, along with this came the understanding that cosmology was exclusive—the
various theories were in competition with each other since they could not all
be true. [It was pointed out by Profs. Möbius and deVries that it was during
this period that concept of a flat earth/watery abyss was discarded. Ways in
which the earth was shown to be round included the round shadow of earth during
a lunar eclipse, the mast of a ship coming towards land was the first part to
be seen, and shadows cast at noon.]
The great philosopher Plato (4th century B.C.E.) had a significant impact on this emerging field. He taught that Ideas (or Forms) alone are real, true, and eternal while material things are temporary, since they are subject to decay. Thus it is not the material world that leads us to truth, but reason (i.e., philosophy and mathematics). The goal of astronomy, according to Plato, was not to observe the sky, but to reason out its “underlying mathematical regularities” (62). This was a radical shift away from astrology, which seeks to observe the heavens to determine the course of events here on earth. I pointed out that, despite the influence of Plato and his followers, astrology remained quite popular in the broader Hellenistic culture. Philip Fernandes argued that there is a significant distinction between academics and hoi polloi (i.e., “the many,” the common people). I replied that, regardless of their brilliance, people like Plato must be understood in their historical context. Plato, for instance, was an Athenian who lived in the 4th century B.C.E. and his ideas were inevitably shaped by this milieu. While it is possible to trace the historical progression of certain ideas, we should not think of Plato as a 21st century man who just happened to be born 24 centuries ahead of his time.
Greek cosmology culminated with the Alexandrian synthesis, named for the city of its origin, Alexandria, Egypt. Founded by Alexander the Great, Alexandria became the intellectual capital of the Hellenistic world—a cosmopolitan hub where many cultures (most notably Greek and Jewish) interacted with each other. Home to the famous Library, the most brilliant minds of the age (e.g., Archimedes1, Euclid, and Eratosthenes) converged there. The city was home to Claudius Ptolemy, the consummate astronomer and geographer of the ancient world. His (rather complicated) model of the universe featured the earth at the center surrounded by a series of rotating spheres (see Figure 1.3 in the link (http://www.shef.ac.uk/physics/people/vdhillon/teaching/phy105/ptolemy.gif)). Ptolemy’s model was later joined with Christian theology to form the Alexandrian synthesis whereby God/heaven lay beyond the realm of the stars with the whole cosmic system being powered by God’s love. Beyond the fallen earth marred by human sin, the heavenly spheres were thought to be perfect. This model would remain virtually unchallenged in medieval Europe until the time of Copernicus. The hierarchical nature of this model was eventually used to justify the legitimacy of rigid systems of hierarchy in the governance of the temporal and the ecclesiastical realms of society.
The first seeds of change were planted during the Crusades (ca. 1100-1300), when European culture collided with that of the Islamic world. A wealth of classical learning, lost to the West in the Dark Ages after the fall of the Roman Empire but preserved in Arabic, became available to Western scholars. When Johannes Gutenberg introduced the printing press to Europe in 1440, making books (and the ideas they contained) vastly more accessible than when they had to be copied by hand, the stage was set for the explosion of learning that would propel Europe into the modern age.
The Scientific Revolution of the 16th and 17th centuries (which came in the wake of the Renaissance and the Reformation) would include a transformation of cosmology, displacing the heavenly spheres and replacing them with the model which has prevailed in the minds of the West up to the present day (albeit with modifications). This process began with Nicolaus Copernicus’ suggestion that the planets following circular orbits around the sun (i.e., a heliocentric model—see Figure 1.4 in the link (http://csep10.phys.utk.edu/astr161/lect/retrograde/copernicus.gif)) in 1543 (thus the process itself became known as the “Copernican Revolution”). However, it was the acquisition of new astronomical data that would prove decisive. Supernovae (in the Milky Way and thus visible to the naked eye) were witnessed in 1572 and 1604. Prof. Möbius added that several comets were also observed roughly during this period. Both of these phenomena pointed to changes in the heavens (i.e., beyond orbit of the moon) and thus could not be explained as part of the medieval model. In Venice in 1609, Galileo built a telescope (a new invention at the time) capable of 30X magnification and pointed it at the heavens. Looking through this telescope he discovered 4 moons around Jupiter, spots on the sun, phases of Venus, and mountains on the moon (as well as what he thought were seas). The data meticulously compiled by astronomer Tycho Brahe and analyzed by Johannes Kepler demonstrated flaws in both Ptolemy’s model as well as Copernicus’—the stars were not moving in the sky over the course of one year. While the data was consistent with heliocentricity, Kepler realized that the orbits of the planets were elliptical, not circular.
Galileo’s publication of his Dialogue Concerning the Two Chief World Systems in 1632 marked a tremendous shift in cosmology, although its magnitude would not become evident until later. The Catholic Church attempted to suppress these new cosmological ideas [ironically defending Aristotle, whose works were practically canonized by the church in the late Middle Ages, rather than the Bible (http://www.ucmp.berkeley.edu/history/aristotle.html)]. Although they succeeded in getting Galileo to retract his statements and put him under house arrest, the authorities were unable to suppress the cosmological revolution which was already under way.
What followed was an unwritten (and uneasy) truce between science and religion referred to as the “Cartesian Bargain.” The Church would abandon its claims to scientific authority as long as scientists would not attempt to influence religious doctrines. In other words, science and religion were divided into two (more or less) completely separate spheres. This issue prompted a great deal of discussion in the class. Mike Dunn then asked the question of why religion persists if so many of its claims have been proven by science to be untrue/not possible. This partially goes back to the question of how the Bible and other sacred texts are to be interpreted: literally or figuratively (see above). Sam Meehan raised the issue of the burden of proof when it comes to miracles. [This is a difficult question. The Bible, for example, is an historical document. Pre-scientific peoples, including the authors of the Bible, had very different standards of proof than we do today. It would be somewhat anachronistic to expect that the Bible or any other ancient sacred text to meet our much more rigorous standards of proof. This, however, doesn’t mean that all miraculous events recorded in such books actually happened. -JC] Erica Westerman, Adam Mirando, and I pointed out that religion is dynamic and there can be and have always been multiple ways of understanding its claims. Prof. Davis mentioned that the Catholic Church has changed its doctrines in light of scientific evidence on several occasions, including rejecting the idea of a young (≈ 6000 years old) earth.
Reminding us of a bigger picture, Erica said that we are focusing on a small slice of human history and culture (i.e., modern Western) and that the separation between science and religion is relatively young. Prof. deVries argued that there was no sense of science and religion being opposed to each other in the minds of the scientific revolutionaries: Copernicus was mostly an astrologer, Kepler was a Pythagorean, and Newton devoted more of his energies to Bible codes and alchemy than to physics. The distinction is rather between seeing religious texts such as the Bible as literal, inerrant truth, or part of a search for truth that should be consistent with science. Prof. Möbius added to this by saying that religion evolves with new ideas encompassing the old. He also argued that, when seen from a more removed perspective, there are many similarities between different religions. The question is: what’s the deeper meaning?
From here the presentation resumed with the culminating figure of the Scientific Revolution, Sir Isaac Newton. His Three Laws of Motion plus his law of universal gravitation provided a mathematical explanation for how the cosmos (at least as then observed) worked—the orbits of the planets and comets around the sun, how the earth could spin without everyone falling off, tides, etc. Newton’s understanding of space as extending indefinitely and void except for matter and forces has prevailed in the common imagination up to the present day.
According to Primack and Abrams, the Newtonian picture of the universe left humanity without a centering cosmology as before. Newton’s cosmology gave rise to existentialism. According to this philosophy we are cosmically homeless—a “random occurrence on an average planet in a vast and uncaring scheme of things” (81). Each individual is essentially alone, “forced to rely on [his or her] own personal interpretation of reality” (82).
However, the authors believe that the Newtonian picture is a 400 year aberration whose time is almost at an end. Recent scientific discoveries have allowed scientists to move beyond it, often in ways that seem counterintuitive and strange to us (e.g., quantum mechanics). The challenge, as Primack and Abrams see it is to integrate all of this new information into a new picture of the cosmos which, like the ancient cosmologies, connects the universe with our own lives in a meaningful way. This new vision should be open enough to leave room for future interpreters, but must let “science set a minimum standard” (86). An illustration of the visible universe (Figure 1.5 in the link (http://www.miqel.com/images_1/space_photos_maps/universe.gif)) marked the end of the presentation.
Prof. deVries began the final discussion by pointing out that he believes Primack and Abrams’ claim that modern science has produced the first cosmology that might actually be true is rather arrogant since changes are still happening. As more doors open we are inching toward the truth, but it’s premature to say we’re basically there already.
Prof. Davis pointed back to Thales (see above), asking whether his ideas represent the source of the distinction between the natural and supernatural. Prof. deVries said that this was difficult to ascertain. Such thinkers could be thought of as instigators of this shift by conceiving of a non-personified system in which mythology did not do all the work of explaining. Prof. Davis then shifted to the present day, pointing to evolutionary biologist [and proselytizing atheist] Richard Dawkins as trying to end this dichotomy by banishing the supernatural altogether. Prof. deVries then interjected that physicists might already have done so. Chris Ives argued that physics does have a realm for God at the boundaries of everything. At this point the question of the “God of the gaps” (i.e., God accounting for as yet unexplained “gaps” in our scientific knowledge) arose. While some of these gaps are closing as our knowledge increases, Prof. Davis argued that some gaps are not being closed at all, with the concept of “random” events being a kind of scientific shorthand for “we don’t really know for sure what’s going on.”
Prof. Möbius then pointed out that the boundaries we were discussing were part of the Western mainstream idea of God. In Eastern religions, God is within everything—there are no gaps or trespasses between the natural and the supernatural. Erica added that, being raised within a church, she never saw any inherent contradiction between the two realms. Then I pointed out that we should not take a simplistic view of religion, even within one (Christianity) there has been an ongoing debate over these questions. [Christians have understood the nature of God in a variety of ways, though conceding that it is fundamentally ineffable. –JC]
The discussion then turned to science. Prof. deVries raised the idea of science as a universal language since it offers a firm hope of proof and agreement. Prof. Davis raised a counterpoint, using Meher Baba as an example, of people marginalizing the importance of science in the “Big Picture.” Chris Ives argued that for people without a great deal of scientific expertise science is akin to religion, since their understanding is based on faith in the experts’ understanding. Prof. deVries countered that this was too simplistic. A systematic (as opposed to atomistic) approach to seeking truth is needed. General beliefs can cover gaps in our understanding. However, they must be part of a coherent “multi-level reason cake,” with reasons being given for reasons.
1Prof. Möbius pointed out that, as a result of the Platonic approach, Archimedes was “poo-poohed” by many of his contemporaries because of his use of the experimental method.