The Reenchantment of the World (5 page)

 

 

In summation, rationalism and empiricism, the twin poles of knowledge so
strongly represented in Descartes and Bacon respectively, can be regarded
as complementary rather than irrevocably conflicting. Descartes, for
example, was hardly opposed to experiment when it served to adjudicate
between rival hypotheses -- a role it retains to this day. And as I have
argued, his atomistic approach, and his emphasis on material reality
and its measurement easily lent themselves to the sort of knowledge and
economic power that Bacon endsaged as possible for England and Western
Europe. Still, this synthesis of reason and empiricism lacked a concrete
embodiment, a clear demonstration of how the new methodology might
work in practice; the scientific work of Galileo and Newton provided
precisely such a demonstration. These men were concerned not merely
with the question of methodological exposition (though each certainly
made his own contribution to that subject), but sought to illustrate
exactly how the new methodology could analyze the simplest events: the
stone falling to earth, the ray of light passing through a prism. Through
such specific examples the dreams of Bacon and Descartes were translated
into a working reality.

 

 

Galileo, in his painstaking studies of motion carried out in the twenty
years preceding the publication of the "New Organon, had already made
explicit what Bacon only implied as an artificial construct in his
generalizations about the experimental method.13 Frictionless planes,
massless pulleys, free-fall with zero air resistance -- all of these
"ideal types" that form the basic problem sets in freshman physics are
the legacy of that Italian genius, Galileo Galilei. Galileo is popularly
remembered for an experiment he never performed -- dropping weights from
the Leaning Tower of Pisa -- but in fact he conducted a far more ingenious
experiment on falling objects -- an experiment that exemplifies many of
the major themes of modern scientific inquiry. The belief that large or
dense objects should strike the ground faster than light ones follows as
a direct consequence of Aristotle's teleological physics, and was widely
held throughout the Middle Ages. If things fall to the ground because they
seek their "natural place," the earth's center, we can see why they would
accelerate as they approach it. They are excited, they are coming home,
and like all of us they speed up as they approach the last leg of the
journey. Heavy objects drop a given distance in a shorter time than light
ones because there is more matter to become excited, and thus they attain
a higher speed and strike the ground first. Galileo's argument, that a
very large object and a very small one would make the drop in the same
time interval, was based on an assumption that could neither be proven
nor falsified: that falling objects are inanimate and thus have neither
goals nor purposes. In Galileo's scheme of things, there is no "natural
place" anywhere in the universe. There is but matter and motion, and we
can but observe and measure it. The proper subject for the investigation
of nature, in other words, is not why an object falls -- there is no
why
-- but
how
; in this case, how much distance in how much time.

 

 

Although Galileo's assumptions may seem obvious enough to us, we
must remember how radically they violated not only the common-sense
assumptions of the sixteenth century, but common-sense observations in
general. If I look around, and see that I am rooted to the ground, and
that objects released in midair fall to the floor, isn't it perfectly
reasonable to regard "down" as their natural, that is to say inherent,
motion? In his studies of childhood cognition, Swiss psychologist Jean
Piaget discovered that until about age seven at the latest, children
are Aristotelians.14 When asked why objects fell to the floor, Piaget's
subjects replied, "because that is where they belong" (or some variation
of this idea). Perhaps most adults are emotional Aristotelians as
well. Aristotle's proposition that there is no motion without a mover,
for example, seems instinctively correct; and most adults, when asked
to react immediately to the notion, will affirm it. Galileo refuted the
proposition by rolling a ball down two inclined planes, juxtaposed as
in Figure 4:

 

 

 

 

 

The ball rolls down B and up A, but not to quite the same height from
which it began. Then it rolls back down A and up B, again losing height;
back and forth, back and forth, until the ball finally settles in the
"valley" and comes to rest. If we polish the planes, making them smoother
and smoother, the ball stays in motion for a longer and longer period
of time. In the limiting case, where friction = 0, the motion would go
on forever: hence, motion without a mover. But there is one problem with
Galileo's argument: there is no limiting case. There are no frictionless
planes. The law of inertia may state that a body continues in motion or
in a state of rest unless acted upon by an outside force, but in fact, in
the case of motion, there is always an outside force, if nothing more than
the friction between the object and the surface over which it moves.15

 

 

The experiment Galileo designed to measure distance against time was
a masterpiece of scientific abstraction. To drop weights from the
Leaning Tower, Galileo realized, was absolutely useless. Simon Stevin,
the Dutch physicist, had tried a free-fall experiment in 1586 only to
learn that the speed was too fast for measurement. Thus, said Galileo,
I shall "dilute" gravity by rolling a ball down an inclined plane,
made as smooth as possible to reduce friction. If we were to make the
slope steeper by increasing the angle Alpha, as in Figure 5, we would
reach the free-fall situation that we seek to explore at the limiting
case, in which Alpha = 90 degrees. Hence let us take a smaller angle,
say Alpha = 10 degrees, and let it serve as an approximation. Galileo
first used his pulse as a timer, and later a bucket of water with a hole
in it which permitted the water to drip at regular intervals. By running
a series of trials, he finally came up with a numerical relationship,
that distance is proportional to the square of the time. In other words,
if an object -- any object, light or heavy -- falls a unit distance in
one second, then it falls a distance of four times that in two seconds,
nine times that in three seconds, and so on. In modern terminology,
s = kt^2, where s is distance, t time, and k a constant.

 

 

 

 

 

Both of these inclined plane experiments illustrate the highly
ingenious combination of rationalism and empiricism which was
Galileo's trademark. Consult the data, but do not allow them to confuse
you. Separate yourself from nature so you can, as Descartes would later
urge, break it into the simplest parts and extract the essence -- matter,
motion, measurement. In general terms, Galileo's was not an altogether
new contribution to human history, as we shall see in Chapter 3; but
it did represent the final stage in the development of nonparticipating
consciousness, that state of mind in which one knows phenomena precisely
in the act of distancing oneself from them. The notion that nature is
alive is clearly a stumbling block to this mode of understanding. For when
we regard material objects as extensions of ourselves (alive, endowed with
purpose) and allow ourselves to be distracted by the sensuous details
of nature, we are powerless to control nature, and thus, from Galileo's
point of view, can never really know it. The new science enjoins us to
step outside of nature, to reify it, reduce it to measurable Cartesian
units; only then can we have definitive knowledge of it. As a result --
and Galileo was not interested in ballistics and materials science for
nothing -- we shall supposedly be able to manipulate it to our advantage.

 

 

Clearly, the identification of truth with utility was closely allied to
the Galilean program of nonparticipating consciousness and the shift from
"why" to "how." Unlike Bacon, Galileo did not make this identification
explicit, but once natural processes are stripped of immanent purpose,
there is really nothing left in objects but their value for something,
or someone, else. Max Weber called this attitude of mind 'zweckrational,'
that is, purposively rational, or instrumentally rational. Embedded
within the scientific program is the concept of manipulation as the
very touchstone of truth. To know something is to control it, a mode
of cognition that led Oskar Kokoschka to observe that by the twentieth
century, reason had been reduced to mere function.16 This identification,
in effect, renders all things meaningless, except insofar as they are
profitable or expedient; and it lies at the heart of the "fact-value
distinction," briefly discussed in the Introduction. The medieval
Thomistic (Christian-Aristotelian) synthesis, that saw the good and
the true as identical, was, in the first few decades of the seventeenth
century, irrevocably dismantled.

 

 

Of course, Galileo did not regard his method as merely useful, or
heuristically valuable, but uniquely true, and it was this epistemological
stance that created havoc with the church. For Galileo, science was not
a tool, but the one path to truth. He tried to keep its claims separate
from those of religion, but failed: the church's historical commitment
to Aristotelianism proved to be too great. In this conflict Galileo,
as a good Catholic, was understandably worried that the Church, by
insisting on its infallibility, would inevitably deal itself a serious
blow. Galileo's life, in fact, is the story of the prolonged struggle,
and failure, to win the church over to the cause of science; and in his
play "Galileo," Bertolt Brecht makes this theme of the irresistibility
of the scientific method central to the story. He has Galileo wander
through the drama carrying a pebble, which he occasionally drops to
illustrate the power of sensory evidence. "If anybody were to drop a
stone," he asks his friend Sagredo, "and tell [people] that it didn't
fall, do you think they would keep quiet? The evidence of your own eyes
is a very seductive thing. Sooner or later everybody must succumb to
it." And Sagredo's reply? "Galileo, I am helpless when you talk."17 The
logic of science had a historical logic as well. In time all alternative
methodologies -- animism, Aristotelianism, or argument by papal fiat --
crumbled before the seductiveness of free rational inquiry.

 

 

The lives of Newton and Galileo stretch across the whole of the
seventeenth century, for the former was born in the same year that the
latter died, 1642, and together they embrace a revolution in human
consciousness. By the time of Newton's death in 1727, the educated
European had a conception of the cosmos, and of the nature of "right
thinking," which was entirely different from that of his counterpart of
a century before. He now regarded the earth as revolving around the sun,
not the reverse;18 believed that all phenomena were constituted of atoms,
or corpuscles, in motion and susceptible to mathematical description;
and saw the solar system as a vast machine, held together by the forces
of gravity. He had a precise notion of experiment (or at least paid lip
service to it), and a new notion of what constituted acceptable evidence
and proper explanation. He lived in a predictable, comprehensible, yet
(in his own mind) very exciting sort of world. For in terms of material
control, the world was beginning to exhibit an infinite horizon and
endless opportunities.

 

 

More than any other individual, Sir Isaac Newton is associated with the
scientific world view of modern Europe. Like Galileo, Newton combined
rationalism and empiricism into a new method; but unlike Galileo,
he was hailed by Europe as a hero rather than having to recant his
views and spend his mature years under house arrest. Most important,
the methodological combination of reason and empiricism became, in
Newton's hands, a whole philosophy of nature which he (unlike Galileo)
was successful in stamping upon Western consciousness at large. What made
the eighteenth century