ABSOLUTE CONCEPTS OF SPACE, TIME, REST, AND MOTION
The ancient
Greek and medieval philosophers described space, time, rest and motion in
abstract, arbitrary and absolute terms; rather than in terms relative to an
object or an observer. In 1687, Isaac Newton
reaffirmed some of these arbitrary and absolute concepts as a part of his
‘theory of measurement,’ and they have continued to influence and distort
scientific thought until the present date.
Throughout history, humans have quite naturally sought to explain mysterious physical phenomena that were not then understood. The natural occurrences of fire, lightning, thunder, earthquakes, volcanoes, hurricanes, floods, and lunar and solar eclipses must have been especially frightening to early mankind.
The first attempted explanations of such puzzling events were primarily supernatural: they were caused by angry spirits, demons, witches, devils, or gods. Such mystical explanations were often accompanied by contrived myths that further attempted to rationalize a baffling occurrence.
The Sun and the stars were particularly bewildering phenomena for many early civilizations. The Egyptians and the Mayans worshipped the Sun because it seemed to provide so many amazing benefits. The Egyptians even invented a Sun god (Ra-Horus) and an early form of astrology to explain and justify the motions of the Sun and stars across the sky, the seasons, and the 26,000-year precession of the Earth on its axis. Later, the Greeks created both a god (Apollo) and a myth (his flaming chariot) to explain the existence of the Sun and its daily motion across the heavens. The Babylonians, Persians, Greeks and the Romans also created many other gods and myths, each to explain a different unfathomable phenomenon.
As knowledge of natural phenomena increased, many scholars moved from the supernatural into the realm of metaphysics (arbitrary and abstract principles). Ancient Greek philosophers believed that the human mind could, by reason alone, discover the great principles and absolute truths that governed all of nature. [1] Aristotle (384-322 BCE), the most prolific and influential philosopher of antiquity, rationalized that there were only five basic elements: air, earth, fire, water, and quintessence.[2] (Collins, p. 31) He stated that the natural place for all objects was being at absolute rest on the face of the Earth.[3] Aristotle conjectured that once each day the planets (‘wanderers’)[4] and ‘fixed stars’ revolve around the stationary Earth, which was located at the absolute center of the universe. Since the circle was considered to be the most perfect geometrical figure, Aristotle also arbitrarily reasoned that the planets must wander around the Earth in absolutely perfect circles.[5] (Bohm, p. 5; see Figure 2.1A) What might Aristotle have said about absolute motion on the Earth? (see Figure 2.2A)
Ancient Socratic philosophers talked in abstract terms of absolute space, absolute rest, and absolute time.[6] These arbitrary spatial and temporal doctrines resulted in certain places and concepts that enjoyed a favored role in nature.[7] (Bohm, p. 5) Such arbitrary concepts were believed to be absolute laws of nature that had been discovered solely through thought and reason. There never was much consideration about observations or experiments to determine whether or not there was empirical support for such rationalizations. (Bird, pp. 20-23)
The absolute doctrines of Aristotle and his brethren continued largely unchallenged in western culture throughout the middle ages. In fact, they were even enhanced and made more rigid by the medieval Scholastics. The Scholastics turned Aristotle’s arbitrary and abstract concepts into rigid axioms or laws of nature that dominated European thinking during the dark ages (Bohm, p. 4), and some of Aristotle’s laws have even influenced physics well into the 20th century. (Bohm, p. 4) The axioms of the Scholastics further contributed to the notion that certain places, times and things played a special or favored role in nature. (Id., p. 5)
As late as the fifteenth century A.D., most civilizations still believed that a flat Earth existed at the center of the universe, and that if one ventured too far in any direction he might fall off the edge. Alchemists continued to believe in the myth that lead could be turned into gold,[8] and physicians of that era practiced the ritual of bloodletting to cure unfathomable physical ailments.
Alchemists and early scientists also concocted bizarre theories and fictitious substances in attempts to explain the bewildering unknown. An imaginary fatty earth substance called ‘phlogiston’ was contrived in order to explain the ingredients that were lost in the flames when something was burned. A fanciful fluid called ‘caloric’ was dreamed up to explain the puzzling phenomenon of heat. Even during the early seventeenth century, Descartes conjectured the existence of a mythical substance called ‘ether’ in order to attempt to explain how light could travel through space. Once accepted into the mainstream of scientific philosophy, spurious concepts like these died slowly. Worst of all, these and other examples of metaphysics created a mindset that tended to restrict reason, to stifle scrutiny and to retard the progress of legitimate science.[9]
During the dark ages, explanation of natural phenomena by means of the
human senses remained a dangerous distraction from eternal salvation and was
thought to be “a corrupting influence on Christian virtue.” (Gleiser, pp. 54-56) Typically, during the 6th century
A.D.,
By the 13th century A.D., theologians were hard at work reinterpreting Aristotle to further the dogma of the Catholic Church.[10] The Holy Fathers had little use for enlightened thinkers such as Roger Bacon (1219-1292), who wrote: “cease to be ruled by dogmas; look at the world.” (Gleiser, pp. 66-67) In 1539, protestant leader Martin Luther sharply criticized Copernicus: “that fool [would] reverse the entire art of astronomy.” (Hartmann, p. 63) Absolute belief continued to rule over empirical observation.
Paradoxically, it was Polish Catholic priest Nicholas Copernicus (1473-1543) who initiated the break with the ‘absolute’ past. In 1512, just 20 years after Columbus discovered America, Copernicus privately distributed a short version of his radical theory that the wandering planets (including the Earth) orbited the central Sun.[11] (Hartmann, p. 63) Copernicus also demonstrated that Ptolemy’s contrived system of epicycles was not necessary if it could be assumed that the planets moved around the Sun. (Figure 2.1B) The concepts of Copernicus shattered Aristotle’s doctrines of favored places in absolute space and special moments in absolute time. Most importantly, the Copernican theory suggested that mankind and the Earth might not occupy the special central position in the cosmos. Rather, Copernicus asserted that the Earth and the other planets moved in orbits relative to the central Sun. [12] These radical relative concepts ushered in a period of skepticism, scrutiny, experimentation, and consideration of the relationships between natural phenomena. (Bohm, p. 6)
By the end of the 16th century, Italian philosopher Giordano
Bruno was theorizing in
A few decades after Copernicus died, skeptical and curious European scholars like Galileo Galilei, Tyco Brahe, Johannes Kepler, and René Descartes began to use observation, experiments and empirical data, in addition to reason, to determine and measure the real causes of natural phenomena. For example, after years of experiments and observations, Galileo discovered and measured the relationship between the time intervals and the accelerated motions of objects falling relatively to the Earth. (see Figures 4.2A and 4.2C) After years of studying Tyco Brahe’s voluminous data based on Brahe’s planetary observations, Kepler finally discovered and measured the relationships of the planets’ orbits relative to the time interval, distance, and orbital path traveled by each planet. (Cohen, 1985, pp. 136 – 140)
For the first time in western philosophy, the role of the observer (or measurer) and his senses became as important as the role of the thinker. Slowly during this early scientific period it was realized that the real causes of natural phenomena resulted from relationships that were purely spatial, temporal, mechanical, chemical, optical, etc. in origin. Gradually it became apparent that the answers for most scientific questions could not be decided by arbitrary and absolute laws, but rather required specific hypotheses, observations, experiments, measurements, and conclusions relative to an object or an observer. This process ultimately became known as the ‘scientific method.’ Nevertheless, the absolute concepts of space, time, rest, and motion resisted change.
In this treatise, we will be discussing theories of measurement as frequently as we discuss substantive principles of physics. The two subjects are often intertwined. “Theories of measurement have been an integral part of theorizing since early antiquity.” (Goldberg, p. 68) They were developed and used in an attempt:
“to
understand how the fundamental primitives…mass, length [space] and time, are
measured and how one relates measurements made in different [moving
bodies].” (
B. Newton’s Theories
of Measurement
In 1687,
Isaac Newton (1642-1727), in his great three-volume work
known as Principia, briefly described, analyzed and somewhat modified
the age-old concepts of space, time,
and motion which became his ‘theory of measurement.’ These age-old concepts and
“Because the parts of [absolute] space cannot be seen, or distinguished from one another by our senses, therefore, in their stead we use sensible measures of them.” (Id., p. 8) “Relative space is some moveable dimension or measure of the absolute spaces, which our senses determine by its position to bodies…” (Id., p. 7)
However,
because the definition of any ‘relative space’ could only be achieved by
reference to ‘absolute space’ (Jammer, 1954, p. 98),
What Newton and his predecessors were attempting to do with their concept of ‘immovable absolute space’ was to hypothetically and metaphorically drive a stake into the void of celestial space which could be considered as immovable and absolutely at rest, and from which their concepts of an absolute place and absolute motion of bodies could be measured. (see Figure 2.2B, and Gondhalekar, p. 95) However, this concept of empty space (nothing) as an absolute place of reference at rest from which the position and motion of material bodies can be measured, on its face, is a meaningless concept.[13]
First of all, the concept of rest can only apply to material objects. How can ‘nothing’ either move or be immoveable and at rest? How can empty space, which is theoretically ‘nothing,’ [14] have the properties of ‘something?’ A priori it cannot.[15] Secondly, since ‘rest’ is a relative concept, what is the nothingness of infinite empty space at rest relative to? More nothing? Thirdly, a place of reference for the measurement of position or motion of material objects must by definition be a tangible, ascertainable position or body.[16] (see Einstein, Relativity, pp. 6-9) Empty space, on the other hand, being ‘nothing’ is completely abstract and intangible. There is no ascertainable position in the nothingness of infinite empty space that could qualify as a tangible place or body of reference.[17] Thus, it follows that there is no such thing as an absolute position at rest or an absolute motion measured from it, and one cannot even determine or measure the relative position or motion of a material body with respect to nothing. (see Dingle, 1940, p. 1)
In effect,
The above discussion answers the question: How can the relative motion of a tangible body through empty space be mathematically described and measured? However, it begs the answer for two other fundamental questions: 1) Does empty space exist, does it have any properties, does it have any meaning, and can it be considered to be a medium? 2) Can something that moves relative to the medium of empty space (i.e. a transmitting ray of light) have any meaning if its velocity cannot be mathematically described or measured relative to such medium?
Of course, the nothing of empty space exists and has meaning in the sense that celestial bodies are constantly observed to exist in it and empty space separates such bodies. It also has meaning as a ‘medium’ in the sense that physical things (including light) move or propagate through it. These are the intangible properties that empty space has, as well as the fact that space appears to be infinite in all directions. The fact that humans have difficulties conceiving of these properties, or that it is difficult for mathematicians to conceive of, describe or measure something (including a constantly transmitting ray of light) having a velocity relative to the medium of infinite empty space, is their problem to deal with. Today, these empirical facts can be precisely measured and verified by sophisticated current technology without the need for any mathematical descriptions or measurements.[19]
Newton’s absolute concepts are quite well known, but it is much less well known that Newton also drew several distinctions between absolute spaces (places), absolute rest, and absolute motions on the one hand, and relative ones on the other, by reason of the observer’s senses and perceptions. For example:
“Relative motion is the translation from one relative place into another…[as where a body] moves together with the ship; and relative rest is the continuance of the body in the same part of the ship…
“…from the positions and distances of things from any body considered as immovable, we define all places; and then with respect to such places, we estimate all motions, considering bodies as transferred from some of those places into others. And so, instead of absolute places and motions, we use relative ones…”
“…for it may be that there is no body really at rest, to which the places and motions of others may be referred…”[20] (Newton, Principia [Motte, pp. 7-8])
Still, it is obvious from the
above discussion that
With regard
to the measurement of time,
One
implication from
In 1679,
It is less well
known that
“…relative, apparent, and common time is some sensible and external…measure of duration by the means of motion…such as an hour, a day, a month, a year” [25] (Id.)
“…absolute time [eternity] is not liable to any change. The duration or perseverance of the existence of things remains the same, whether the [relative] motions are swift or slow, or none at all…” (Id., p. 8)
Thus,
There is no doubt that Newton
reaffirmed some of the ancient arbitrary and absolute concepts about space,
time, rest, and motion, and that these concepts continued to influence
scientific thought well into the 20th century. Still, it is important to realize that
At this point, perhaps we should pause and ask the questions: Why are we, in the twenty-first century, even discussing these ancient, absolute, amorphous and imprecise concepts of space and time measurement? What relevancy do they have to this treatise? The answers are as follows.
During
What is the underlying message of
this chapter? Is it that assumptions and
theories that appear to be reasonable and have passed the test of time may, in
fact, be invalid? Is it that an
authoritative stamp of approval does not mean that a hypothesis is correct? Is it that invalid, absolute concepts may
masquerade as valid, relative ones? Is
it that established theories might be demonstrated to be wrong when scrutinized
in a different way, or by different people?
Or is it that scientific icons, like
[1] A similar philosophy is held by current mathematical physicists, except that ‘mathematics’ is now substituted for ‘reason,’ logic and commonsense. For the ancient Greeks, an ‘absolute truth’ was one that held under all conditions and all circumstances. (Bohm, p. 1)
[2] According to Aristotle, ‘quintessence’ was the stuff that astronomical bodies were made of, but it was not found on Earth. (Collins, p. 31)
[3] According to Aristotle, an object’s natural place was considered to be an ‘internal’ (inherent) principle or property of the object. An ‘external’ cause (not inherent to the object, such as force) was required to release the object so that it would fall and seek its natural place at rest on the Earth. (Bohm, pp. 4, 5)
[4] The Greeks called the planets “wanderers” because they appeared to slowly move or wander with respect to the ‘fixed stars.’ (Hoffmann, p. 5)
[5] By the time of Claudius Ptolemy (c. 130 AD), it was observed that the planets did not orbit the Earth in perfect circles. So in order to remain consistent with Aristotle’s arbitrary dogma, Ptolemy invented the cumbersome concept of ‘epicycles,’ or circles upon circles, to explain the observed orbits of the planets.
[6] They even discussed the abstract idea of absolute cold, which was independent from anything that was cold. (Bird, p. 21) However, the fact that every terrestrial motion must be relative to something was even known to some ancient Greeks. (Pavlovic, section 1, p. 1)
[7] For example, Aristotle gave the Earth the favored role of being absolutely at rest and at the center of everything. (Bohm, p. 8)
[8] ‘Alchemy’ was an early form of chemistry.
[9] The same is currently true of many ad hoc mathematical theories, such as Special Relativity.
[10] For
instance, the outermost sphere of Aristotle’s finite and spherical universe was
decreed to be “the dwelling place of God.”
(Gleiser, p. 66) Also see
[11] A similar heliocentric theory had been advanced by the Greek philosopher Aristarchis in the third century BCE (Hoffmann, p. 8) and Copernicus was aware of it, but it was not generally known even among western scholars.
[12] Copernican theory only became generally known when it was published after his death in 1543. The Catholic Church then attempted to ban it and suppress its distribution, but the genie was already out of the bottle.
[13] When we refer to the theoretical nothingness of ‘empty space’ in this treatise, we are referring to the theoretically perfect vacuum of empty space independently from the radiation, atomic particles or other things that may pass through it.
[14] The universe is almost entirely empty space: nothing. If all of the matter and radiation in the observable universe was smoothed out and distributed evenly throughout endless space, then each spatial area the size of the Earth would contain only one grain of sand. (see Hubble, 1936A, p. 31) Expressed differently, every cubic foot of space would contain only about 3 or 4 protons. “That is about a million million times less than that of the most perfect vacuum that we can produce in our physical laboratories.” (De Sitter, Kosmos, 1932, p. 119)
[15] The term ‘A priori’ in this treatise means ‘according to theory,’ or ‘from cause to effect.’
[16] As Einstein pointed out: “Every description of events in space involves the use of a rigid body to which such events have to be referred.” (Einstein, Relativity, p. 9)
[17] If a place of reference is everywhere,
such as ‘absolute space’ or the theoretical ether, then it cannot really be a
‘place’ with a position.
[18] What cannot ever be determined, measured or estimated is: 1) The absolute position (place) of the Earth (or any other object) in the Cosmos; 2) The absolute motion or velocity of the Earth (or any other object) through celestial space; and 3) The absolute direction or trajectory of any moving objects.
[19] This discussion will become very relevant when we discuss the transmission velocity of light in later chapters.
[20] These
concepts may be considered as
[21]
[22] It turns out that all events in the Cosmos most likely do occur simultaneously, but they are not perceived by a distant observer to be simultaneous, because the light signal has a finite velocity. Therefore, there is a time interval from emission of light to its perception by a distant observer and as a consequence such simultaneity has no meaning for such distant observer. (see Chapter 25)
[23] Miller gave the following example: “if an observer at a point A flashed a beam of light to an observer at a point B, then the observer at B could conclude that the time at which he receives the light ray is coincident with its time of emission from A.” (Miller, p. 174)
[24] In Chapters 6 and 7, we shall discuss Römer’s theory in detail, as well as Bradley’s 1728 empirical confirmation thereof.
[25] Other
examples of something “external” (not inherent in
[26]
Much later, Einstein’s mentor, Ernst Mach, would write that “absolute time” was
a useless concept with no practical value, because duration (eternity) could
not be measured, and that, except for relative measures of time (i.e. clocks),
there was no “time in itself.” (see
Folsing, pp. 174, 175) But even though
[27] “Even in Newtonian mechanics there was a strong element of relativity. Einstein was therefore not the first to introduce relativistic notions into physics.” (Bohm, p. 10)