1 The Ultimate Question
13
take place in the realm of science. However, an eloquent demonstration of
this is the centuries-long dispute about the nature of light.
Even in antiquity the ancient Greeks had wondered about this issue, but
for brevity let us jump directly to Newton’s Corpuscular Theory of Light
(1704), in which a light ray was considered to comprise a beam of particles. Newton’s proposal was generally accepted as true until Thomas Young
in 1803 carried out an experiment that involved the diffraction 5 of light
from two slits, thereby proving that light must have a wave-like nature. This
was consolidated in the second half of the 19th Century, when James Clerk
Maxwell (and others) interpreted light as a form of electromagnetic radiation.
At this time, Newton’s corpuscular theory was totally discarded as a somewhat
quaint relic of a bygone era.
This rejection, however, turned out to be short-lived. The triumph a few
decades later of Quantum Mechanics (QM) revealed that the corpuscular and
wave characters of light are actually two different facets of the real nature of
light, rather like the two sides of a coin. Both are correct, but they are incomplete and complementary, since both must be considered for a complete
description of the observed phenomenology. This duality of QM has been
extended from light to matter, as particles (electrons, protons, etc.) have been
found in certain circumstances to exhibit a wave-like behaviour (see Chap. 5).
So, as we have seen, both the corpuscular and wave natures of light were
considered at various times to represent the truth, but in effect they were both
only provisional interpretations of the reality. Likewise, whatever we believe
to be true in our time might in turn become outdated, if and when a higherlevel “truth” is discovered. In Part 3 of this book, we will argue that some of
the current discrepancies between otherwise quite successful theories might
be due to their incompleteness, and we will search for hints that might allow
us to look ahead in our quest.
At this point it might be interesting to ask what has happened to multiple
truth doctrines and whether they are still acceptable. From a scientific point
of view, the double truth doctrine helped scientists like Copernicus and his
followers avoid being burnt at the stake. They claimed with sincerity that
two conflicting truths could coexist, since they belonged to totally different
domains: reason and religion. Others, such as Isaac Newton, held unorthodox
religious views that they kept largely to themselves to avoid the consequences
of the Blasphemy Act of 1697, which could have seen them stripped of all
property and even sentenced to death.
5 Light passing through two slits produces a pattern of light and dark bands, caused by interference
between the two components of the beam that passed through each of the slits. See Chap. 5.
13
take place in the realm of science. However, an eloquent demonstration of
this is the centuries-long dispute about the nature of light.
Even in antiquity the ancient Greeks had wondered about this issue, but
for brevity let us jump directly to Newton’s Corpuscular Theory of Light
(1704), in which a light ray was considered to comprise a beam of particles. Newton’s proposal was generally accepted as true until Thomas Young
in 1803 carried out an experiment that involved the diffraction 5 of light
from two slits, thereby proving that light must have a wave-like nature. This
was consolidated in the second half of the 19th Century, when James Clerk
Maxwell (and others) interpreted light as a form of electromagnetic radiation.
At this time, Newton’s corpuscular theory was totally discarded as a somewhat
quaint relic of a bygone era.
This rejection, however, turned out to be short-lived. The triumph a few
decades later of Quantum Mechanics (QM) revealed that the corpuscular and
wave characters of light are actually two different facets of the real nature of
light, rather like the two sides of a coin. Both are correct, but they are incomplete and complementary, since both must be considered for a complete
description of the observed phenomenology. This duality of QM has been
extended from light to matter, as particles (electrons, protons, etc.) have been
found in certain circumstances to exhibit a wave-like behaviour (see Chap. 5).
So, as we have seen, both the corpuscular and wave natures of light were
considered at various times to represent the truth, but in effect they were both
only provisional interpretations of the reality. Likewise, whatever we believe
to be true in our time might in turn become outdated, if and when a higherlevel “truth” is discovered. In Part 3 of this book, we will argue that some of
the current discrepancies between otherwise quite successful theories might
be due to their incompleteness, and we will search for hints that might allow
us to look ahead in our quest.
At this point it might be interesting to ask what has happened to multiple
truth doctrines and whether they are still acceptable. From a scientific point
of view, the double truth doctrine helped scientists like Copernicus and his
followers avoid being burnt at the stake. They claimed with sincerity that
two conflicting truths could coexist, since they belonged to totally different
domains: reason and religion. Others, such as Isaac Newton, held unorthodox
religious views that they kept largely to themselves to avoid the consequences
of the Blasphemy Act of 1697, which could have seen them stripped of all
property and even sentenced to death.
5 Light passing through two slits produces a pattern of light and dark bands, caused by interference
between the two components of the beam that passed through each of the slits. See Chap. 5.