1 The Ultimate Question
11
Nowadays, optical illusions are considered nothing more than amusing
curiosities. The ancient Greeks, however, took them as proof of the deceitful
nature of our senses. In his famous Cave Allegory [3], Plato compares men to
slaves enchained in a dark cave with a blank wall before them. Other beings
come and go, but the slaves cannot see them. The only evidence of their
presence is their shadows, projected onto the wall by a fire behind them.
Most slaves believe that the shadows they see are indeed the reality, but the
philosophers among them try to reconstruct and ascertain what is actually
going on.
Nor is it only our eyes that cannot be trusted. Our reason can also lead
us astray, as was illustrated by the Greek, Zeno of Elea (ca 490–430 BCE),
in a series of intriguing paradoxes. In his most famous example, he assumes
that Achilles has a footrace with a tortoise, to which he gives a head start
of 100 m. During the time it takes Achilles to cover the 100 m, the much
slower tortoise advances a distance of (say) 10 m. Likewise while Achilles
covers those extra 10 m, the tortoise keeps going for one more meter, and
so on. Since the process goes on ad infinitum, Achilles will never be able
to reach the tortoise because of the infinite number of steps required. The
resolution of this paradox requires a realisation that the sum of an infinite
number of finite quantities can actually be finite. (A simple example of such
a summation is given in Appendix 1.1)
Another troubling issue for the Greeks was the ephemeral nature of life.
If we see a horse, can we really say that it exists? After all, a few years ago it
did not exist and in another few years it will have died, and passed back into
oblivion. Can such a temporary condition really be called existence? Shouldn’t
we rather say that what exists is not the individual horse, but rather the form
or idea of a horse, i.e. the equinity? Even if horses did not exist in the past,
or will not exist in the future, surely the idea of a horse must have always
existed.
Nowadays we know that not only appearances can be deceptive, but also
that most of the world is completely beyond the grasp of our five senses. Even
without entering into the most recent advances, such as dark matter and dark
energy (which will be touched upon in later chapters), we all know that our
senses of vision and hearing are both very limited, being constrained to the
narrow range of frequencies (or wavelengths) of light and sound that our eyes
and ears can capture. (These limits are detailed in Appendix 1.2.) Curiously
enough, science warns us that the inadequacy of our senses is much deeper
than ever anticipated by the ancient Greeks, but also it provides us with the
tools to interpret the reality beyond.
11
Nowadays, optical illusions are considered nothing more than amusing
curiosities. The ancient Greeks, however, took them as proof of the deceitful
nature of our senses. In his famous Cave Allegory [3], Plato compares men to
slaves enchained in a dark cave with a blank wall before them. Other beings
come and go, but the slaves cannot see them. The only evidence of their
presence is their shadows, projected onto the wall by a fire behind them.
Most slaves believe that the shadows they see are indeed the reality, but the
philosophers among them try to reconstruct and ascertain what is actually
going on.
Nor is it only our eyes that cannot be trusted. Our reason can also lead
us astray, as was illustrated by the Greek, Zeno of Elea (ca 490–430 BCE),
in a series of intriguing paradoxes. In his most famous example, he assumes
that Achilles has a footrace with a tortoise, to which he gives a head start
of 100 m. During the time it takes Achilles to cover the 100 m, the much
slower tortoise advances a distance of (say) 10 m. Likewise while Achilles
covers those extra 10 m, the tortoise keeps going for one more meter, and
so on. Since the process goes on ad infinitum, Achilles will never be able
to reach the tortoise because of the infinite number of steps required. The
resolution of this paradox requires a realisation that the sum of an infinite
number of finite quantities can actually be finite. (A simple example of such
a summation is given in Appendix 1.1)
Another troubling issue for the Greeks was the ephemeral nature of life.
If we see a horse, can we really say that it exists? After all, a few years ago it
did not exist and in another few years it will have died, and passed back into
oblivion. Can such a temporary condition really be called existence? Shouldn’t
we rather say that what exists is not the individual horse, but rather the form
or idea of a horse, i.e. the equinity? Even if horses did not exist in the past,
or will not exist in the future, surely the idea of a horse must have always
existed.
Nowadays we know that not only appearances can be deceptive, but also
that most of the world is completely beyond the grasp of our five senses. Even
without entering into the most recent advances, such as dark matter and dark
energy (which will be touched upon in later chapters), we all know that our
senses of vision and hearing are both very limited, being constrained to the
narrow range of frequencies (or wavelengths) of light and sound that our eyes
and ears can capture. (These limits are detailed in Appendix 1.2.) Curiously
enough, science warns us that the inadequacy of our senses is much deeper
than ever anticipated by the ancient Greeks, but also it provides us with the
tools to interpret the reality beyond.