Cosmic Understanding

Philosophy and Science of the Universe

Milton K. Munitz

• Publisher: Princeton University Press
• Year: 2021
• ISBN:
  9780691228143
• Topic: Philosophy
• Subtopic: Philosophical Metaphysics

The description for this book, Cosmic Understanding: Philosophy and Science of the Universe, will be forthcoming.

ONE

The Search for Cosmic Understanding

COSMOLOGY

Every living creature interacts with its environment, its world, in ways that are appropriate to its capacities, needs, and resources. Every organism seeks to “comprehend” (in some way to take in) its world in the effort to meet its needs. These needs are of different kinds. Some are typical of the species, others idiosyncratic. Some are recurrent and persistent, others transitory and occasional. Put a puppy in a room and it explores that world in order to find out as much as it can, to test experimentally whether its ways of grasping or sensing might give it satisfaction. The interactions of human beings with their world are carried out in more complicated and diverse ways, on different levels, and in different directions. As distinguished from other organisms, a characteristic capacity of human beings for dealing with their world is to use understanding and practical intelligence, and thereby gain more effective control. Here again, the special forms in which this will be achieved will vary widely.

In the above paragraph, the term “world” was used somewhat loosely. Since it can also be given different special senses, let me single out a group of meanings—indeed a subclass of these—that will be of special interest to us in what follows. There is an entire class of metaphorical uses that, once noted, we shall put aside as not relevant to our present concern. Thus the term “world” may be employed to refer to some special domain of interest or preoccupation. It was this type of use that was involved in my earlier reference to the room in which a puppy is placed as its “world.” It is this metaphorical sense, too, that appears, for example, in such expressions as “the business world,” “the art world,” “the computer world,” “the world of international affairs,” and so on. When used in this way, a person normally participates in several different “worlds. ” Thus there is nothing to prevent someone from being a participant in “the world of mathematics,” “the tennis world,” and “the world of chamber music,” among others. However, this metaphoric use of “world,” though enjoying widespread everyday usage, is one I shall largely ignore in the present investigation.

We come closer to our special interest by confining attention to the use of the expression “world” in astronomical contexts. Here we find that in ordinary usage the term still enjoys a certain multiplicity of senses, since it is used interchangeably with various distinct, more technical astronomical expressions. For example, the term “world” may be employed as a name for our planet Earth or as a designation for any other planet in the solar system. The term “world” is also sometimes used to refer to a star, or, still more inclusively, to a galaxy. Finally, the term “world” may be used to designate the most comprehensive astronomical system of all—the world as a whole. The preferred technical expression for this most inclusive astronomical system is “the universe." It is this last astronomical meaning of the term “world” with which we shall be principally concerned in this book. So understood, the world (the universe) is the primary subject matter for cosmology. The term “cosmology,” as its etymology indicates, is an inquiry into or discourse about the cosmos. Since the expressions “cosmos,” “the universe,” and “the world as a whole” are frequently interchanged in popular astronomical usage, we may define cosmology—in a preliminary, rough way—as an inquiry into or discourse about the world as a whole.

One of the characteristic, persistent, and irrepressible needs of the human mind is to have a cosmology. It consists in the interest of being able to describe and understand the large-scale, global structure of the universe in which we live. An interest in cosmology, as just briefly described, is to be found in virtually every period and culture of recorded history. When seen in this broad perspective, contemporary scientific cosmology is a very special illustration of this persistent human interest. In one form or another, human beings had sought to satisfy it long before science emerged. Cosmology had been pursued, and for certain cultures is still pursued, under a variety of nonscientific auspices. Men will call upon whatever resources, methods, and faculties they are prepared to rely on in obtaining a satisfactory description of the world. Their acceptance of a cosmological scheme will accordingly vary with the different, often conflicting and rival methods for acquiring and justifying beliefs. Where creative imagination and the power of thought are not exercised in a controlled and critical way, as they are in science, men will fall back on the imaginative appeal of some poetic myth, an unquestioning faith in a sacred religious text, or some purely philosophical scheme of thought.

Contrasted with the foregoing is the method for warranting beliefs held in science. In the case of contemporary scientific cosmology, this method rests on the use of detailed observation, the interpretation of empirical data by theories of physics, and the use of mathematical or other modes of logical reasoning contained in these theories. The task of the cosmologist is to explain relevant astronomical and other empirical data, and in so doing, to give an account of the spatial, temporal, and compositional structure of the universe. He does this by constructing a conceptual system, a model of the universe. It is through the mediation of an accepted cosmological model that he claims to possess an understanding of the universe.

Whether pursued as a scientific discipline or in some other way, the need to have a cosmology, an acceptable picture of the universe, generally derives from two principal motives. One is curiosity, a purely intellectual craving and sense of wonder that prompts the asking of certain questions. To accommodate all the various methods used in obtaining and sanctioning a cosmology mentioned above, we can identify four major types of questions that human beings typically and repeatedly have raised in expressing their curiosity about the world. As ordinarily phrased, they ask: (1) “Did the universe have a beginning, or was it always in existence?” (2) “Is there a spatial limit to the universe, or is it of infinite spatial extent?” (3) “What are the basic materials and major units of which the universe is composed?” (4) “Is there a purpose or design to the universe that would explain both its existence and its various structural features?” These are questions about the temporal, spatial, compositional, and teleologic properties of the universe. Scientific approaches to cosmology have generally confined themselves to the first three types of questions, whereas cosmologies that are based on myth, religion, and some metaphysical speculations have also sought to give answers, of one sort or another, to the teleologic question.

A second motive underlying the search for a satisfying cosmology derives from the human need to “situate” the life of human beings in the universe. We wish to know our “place,” where we fit in among all the other entities that make up the universe. What forces, powers, and causes brought us into existence and sustain us? What should be our goals, purposes, and values? Is there some cosmic design of which our lives are a part? Being able to answer these kinds of questions is one way of responding to what is frequently referred to as a search for the meaning of life.

The combination of these two motives—that of sheer curiosity and that of finding the broader cosmic pattern of which our lives are a part and that would contribute to finding a meaning in life—has been the principal sustaining incentive in the pursuit of cosmology. For some individuals, one or another motive may dominate; for example, the curiosity motive may be uppermost for some scientific cosmologists. At the same time, we must also recognize that not all human beings share an interest in cosmology to the same degree—some have only the most fleeting and superficial interest, whereas others may make it their dominant intellectual passion and preoccupation.

When cosmological questions are seen historically or on a large canvas that describes the intellectual life of an entire period or culture, there is also great variability in the amount of attention given to them. In some periods or in the life of some societies, the focus of attention may be so concentrated on more immediate problems of a practical sort—for example, on sheer survival or on economic or political problems—that an interest in the world on a cosmic scale is a remote and unavailable luxury, a luxury for which there is neither time nor energy. Or it may be, too, that when attention is given to it, the account accepted by the group and transmitted to the individual is of a perfunctory and traditional sort. Once learned, the standard account is accepted in an unquestioning spirit. In such periods and for such cultures, cosmology is not among the dominant or active foci of attention or radical change.

However, this is surely not the case at the present time, at least wherever science plays a major role in shaping the thought and beliefs of people. Indeed, along with revolutionary developments in other sciences—for example, particle physics or molecular biology—scientific cosmology has aroused a great amount of interest. Newspapers, books, and other media report to a wide audience the latest discoveries and theories of the cosmologist. The result has been to put scientific cosmology in the forefront of scientific disciplines that have engaged the attention of an increasing number of scientific specialists, at the same time that the fruits of that research, as communicated to a wider public, have aroused great interest and promise. In all of this ferment there is much fascination and a strong sense of anticipation, shared by active participants and interested bystanders alike, in the outcome of ongoing research. One cannot help wonder whether scientists are finally on the verge of solving the grandest riddle of all. Are they within striking distance of laying bare the real structure of the universe? Would not such an achievement be of momentous proportions and have the most profound consequences? There is understandable excitement in keeping abreast of the direction and details of current inquiries in cosmology.

This phenomenon is a relatively recent one. The proliferation and elaboration of various sophisticated models of the universe, based on the results of the most advanced data-gathering instruments and the interpretation of these findings by concepts of the most highly regarded and well-tested theories of mathematical physics, are a striking and important feature of contemporary cosmology. It is a phenomenon that is only several decades old, having begun in 1917 with Einstein’s pioneering cosmological investigations, based on the theory of relativity, and with Edwin Hubble’s important observational researches in the 1920s into the “realm of the nebulae. ” Progress ever since has been made possible by the introduction of increasingly more powerful instrumental and conceptual resources.

Optical and radio telescopes have probed the large-scale spatial depths of the universe to enormous distances of billions of lightyears.¹ Some radio sources (and possibly also some quasars) are so many billions of light-years away that radiation from them, reaching us only now, has been traveling from a time when the universe was only 10 or 20 percent of its present age. The basic macroscopic units of the universe consist of clusters of galaxies. These range in size from relatively small clusters such as our own Local Group, numbering approximately twenty, and containing our own Milky Way Galaxy, to clusters having thousands of member galaxies. Light takes several million years to traverse a cluster of average dimensions. The largest clusters are 100 million light-years across.

In addition to its spatial properties, another, perhaps even more remarkable feature of the universe, as established by cosmology in our time, is that the universe, when considered from a large-scale temporal point of view, is not unchanging, but shows an underlying pattern of expansion. Already by the late 1920s, confirmation had been given to the idea that the universe is undergoing a systematic expansion. For a brief period, beginning in the late 1940s and continuing into the early 1960s, there was a lively debate between those who favored a steady-state (“continuous creation”) 1 model of the expanding universe and those who argued for an evolutionary conception according to which the universe had a definite origin in the finite past. This debate was eventually settled in favor of the evolutionary conception.

The content of these latest scientific ideas is embodied in various models of an evolutionary expanding universe. One such account is “the standard hot big-bang model” of the expanding universe. It describes the early stages in the career of the universe and the subsequent evolutionary developments of its major constituents. The model incorporates basic concepts of the theory of relativity and other relevant branches of physics. It is supported by much observational evidence. According to this model, the universe had its origin approximately 15 billion years ago. Since then, the universe has already undergone or encompassed a variety of evolutionary and transformational processes—nuclear, atomic, molecular, galactic, stellar, planetary, biological, and human-cultural. It may be expected to undergo still further changes, and will eventually meet its own inevitable death in one form or another in the far off, yet foreseeable future.

The belief that the world as a whole possesses an inherently developmental structure has always exercised a strong imaginative and intellectual appeal. Men have repeatedly been attracted to the thought that if we could somehow establish that the underlying structure of the world consists of a beginning and distinct subsequent stages, then we should have the basic schema at hand for understanding its overall plan. Such a schema would be valued even if not all the details necessary to fill it out were known or perhaps even knowable. The attraction of this type of model in the search for cosmological intelligibility is exhibited from the earliest stages of human culture, where it takes the form of a widely assorted array of primitive myths and religious cosmogonies. It is found, too, in a number of proto-scientific cosmogonies proposed by several pre-Socratic Greek philosophers in the sixth and fifth centuries B.C. What is impressive, exciting, and conducive to the deepest thoughtful consideration is the fact that the same appeal to a developmental or evolutionary cosmology is also given strong support by the most responsible efforts of current scientific cosmology.

THE HUMAN SIGNIFICANCE OF CHANGES IN COSMOLOGY

Because of the great interest in, and significance of, these recent investigations in cosmology, we are faced with a situation that, in its possible widespread impact on our most fundamental human attitudes and beliefs, is comparable to earlier eras in which radical intellectual changes of a general sort were instigated by revolutionary scientific developments. A clear instance of this sort of phenomenon is to be found in the initial shock and later aftermath of the Copernican revolution. This momentous event marked one of the first major stages in the gradual dissolution of the medieval world picture, a way of thought that held sway for more than a thousand years. Let us pause, briefly, to recall some aspects of that earlier upheaval before considering our own present situation.

In shifting from a geocentric to a heliocentric conception of our planetary system, the major dislocation in man’s cosmological outlook brought about by the Copernican revolution was initially only spatial in character. The Earth was displaced from its central position in the finite universe. This shift brought with it, however, major repercussions in a variety of directions, not the least of which was man’s view of his own place in the entire scheme of things. According to the prevalent medieval world picture, the cosmos was centered on the Earth. Man, created in God’s image, was the pinnacle of creation. He was placed on the Earth so that he may use all that it contains to work out his salvation and thereby fulfill God’s providential and benevolent design. However, with the demotion of the Earth from its hitherto central astronomical position in the cosmos, doubts began to creep in about man’s claim to a uniquely privileged status and role. In the ensuing centuries, this spatial reorientation forced a number of other modifications and encouraged the fashioning of new ways of thinking on a variety of fronts. Taken together, these changes brought about the eventual overthrow of some of the main pillars of the hitherto dominant medieval cosmology.

The main features of that cosmology consisted of three strands: Biblical cosmogony, Aristotelian physics, and Ptolemaic astronomy. Thus in Aquinas and Dante, as major spokesmen for the medieval outlook, we find each of these components.

The first strand in medieval cosmology, Biblical cosmogony, articulated the central theistic belief that God, as a transcendent, immaterial, eternal, and perfect Being, created ex nihilo the world and all that it contains. Much of traditional theology took the words of Genesis literally. It accepted as an article of faith the account there given of the act of Divine Creation of the world. The Creation was a unique event that took place in the finite past, an event of transcendent mystery. It linked the infinite omnipotence and goodness of God with the contingent existence of the world and all that it contains. For medieval man, various types of entities were thought of as manifesting different gradations and as occupying different locations in the great “chain of being.” The chain stretched from the lowest, innermost circles of Hell, through the intermediate domain of man’s temporary abode in an earthly vestibule between two eternities, to the highest zones of Heaven where dwell the blessed immortal souls of men, the angels, and the Infinite Mind of God.

The second strand in medieval cosmology, Aristotelian physics, involved a radical distinction between terrestrial and celestial physics. In order to describe the astronomic, cosmologic, and other physical details of the world as created, medieval theology fused, as best it could, the account of Genesis with the inherited dogmas of Aristotelianism and Ptolemaic astronomy. Terrestrial phenomena (those “below the sphere of the Moon”) were constituted of, and depended on the distinctive properties and interrelations of, the four basic elements—earth, water, air, and fire. By contrast, celestial phenomena required an understanding only of the quintessential ethereal element, out of which all the perfect, unchanging heavenly bodies were thought to be composed.

The third pillar of medieval cosmology consisted of the paradigm that the various heavenly bodies (Sun, Moon, planets, and fixed stars) revolved around the fixed, central Earth. The geometric and kinematic patterns of their individually distinct motions were to be constructed out of circles in various combinations and patterns—deferents, equants, epicycles, and eccentrics.

All of this doctrine had been worked out in elaborate and polished detail. It was part of the common, inherited, and unquestioned intellectual and religious world picture of medieval man. To disturb even the purely astronomic and cosmologic framework of this world picture was to threaten the viability and coherence of the entire scheme. It could not be tolerated, and for a long time it was not. It suffices to remember the “crime” of Galileo in subscribing to the Copernican astronomy, and how it was the source of his condemnation by the Church. It is a historically clear and important example of how serious an offense it was for science to challenge traditional beliefs.

The principal immediate change intended and brought about by Copernicus, in his great work De Revolutionibus Orbium Caelestium (1543), affected only th...

Table of contents

• Cover Page
• Title Page
• Copyright Page
• Contents
• Preface
• 1. The Search for Cosmic Understanding
• 2. Cosmology at the Dawn of Western Thought
• 3. The Universe
• 4. The Beginning and End of the Universe
• 5. Cosmic Horizons
• 6. The Boundless
• 7. Human Existence
• Index