|
2 Boyle “On the
Excellency and Grounds of the
Corpuscular or Mechanical Philosophy” (Matthews,
109-118)
-
G.W. Leibniz from
the Preface to New essays on human understanding According to the traditional,
Aristotelian view, change occurs when a body with an active potency to
transmit a form comes into contact with another body with a corresponding
passive potency to take on that form. As noted in the previous chapter, this
view is still reflected in some of Bacon’s pronouncements. Butt the active powers, forms and passive
potencies that Aristotle supposed are behind all change in nature are
mysterious. They work in hidden and
often arbitrary ways. Sunlight melts
wax but hardens clay. The processes by
which one and the same “active” brings about such different changes in two
different “passives” are not evident to us.
They result from “nature working within,” as Bacon said in one
place. Saying, “The change occurs
because sunlight has the active potency to transmit both the form of fluidity
and the form of hardness, but wax only has a passive potency to take on the
form of fluidity, while clay is the opposite,” does no more than report on
the fact that one type of change occurs in one circumstance, another in
another. Such knowledge is not to be
disparaged. But if we are constrained
to find out what things will happen in what circumstances only after the
fact, by performing the experiment and waiting to see what happens, then we
end up being confronted with an impossibly large research project. Combining all different materials in all
different ways in all different proportions under all possible circumstances and
waiting to see what happens after two minutes, ten minutes, three days, ten
years, etc., is more than the largest and best funded research institution
could possibly undertake. Things would be much
better if, instead of containing a large variety of different materials,
differing in weight, solidity, hardness, elasticity, charge, explosiveness,
and various other kinds of reactability, nature
contained just one kind of material.
Things would be better yet if that one kind of material were totally intert — if it had no qualities to speak of, but was just
cut up into little pieces of varying sizes and shapes, and these pieces were
not attractive or repulsive, or active in any way, but simply moved around as
a consequence of how they had collided with one another. In that case there would be no mysterious
forces or qualities that could only be discovered in materials by
experience. Learning the laws of
motion and collision and learning where each small piece happens to be
located and how it happens to be moving would put us in a position to
calculate what would happen next and how to intervene in the course of nature
to shape events. Already in ancient
times there had been a minority view (that of Leucippus and Democritus,
Epicurus and Lucretius), that everything just consists of inert “atoms,” all
like one another except for their size, shape, location, and state of
motion. The atomists took all the
differences in weight, solidity, hardness, elasticity, and so on in the
compound bodies we see around us to be consequences of how the small, inert
particles composing those bodies are arranged and interlinked. Thinkers in early modern Europe, looking
back at these ancient texts, saw that they presented a view of nature that,
if correct, would significantly abbreviate the amount of empirical research
we would otherwise need to do, would remove all the mysteries in nature (by
reducing active forces and passive potencies to the effects of readily
intelligible motions and collisions of particles), and would put us in an
even better position to gain power over nature in order to improve the
material conditions of life. That made
the atomist view very attractive. Another thing that
made the atomist view attractive was its conformity to current technological
practices. Inventions like the wind
mill, the printing press, and the mechanical clock, which had revolutionized
life in the period, consisted of parts that worked by moving and pressing on
or pulling one another. The effects
produced by these devices were not mysterious. We could look into the machine and see how
the originally impressed force traveled along the gears, axels, wheels,
levers, and pulleys to produce the blast from the bellows, the printed page,
or the motion of the hour and minute hands.
And Bacon had declared that the investigation of nature ought to
proceed by paying special attention to artefacts of human invention, because
the artificial does not differ from the natural except for the fact that
different beings are responsible for making it. The laws in accord with which the one works
should be the same as those in accord with which the other works. We should, therefore, be able t take
mechanical devices as a model for the way nature works, and be able to
suppose that all of nature’s effects are the products of a mechanism with
colliding and moving parts. Of course there were
notable exceptions. The magnetism
exhibited in the workings of the compass and the explosive chemical reaction
of gun powder resisted explanation by mechanical means. In these cases there still seemed to be
some hidden force of a non-mechanical kind responsible for the
phenomena. But thinkers of the time
hoped that the exceptions were merely apparent, and
that further investigations would reveal a machine responsible for the
operation rather than leave us having to accept the existence of further
inexplicable powers residing in fundamentally different kinds of
material. Bacon himself thought that a
program of exhaustively combining all different kinds of materials in all
different proportions and under all conceivable circumstances would be
impossible to complete and unlikely to lead to any significant results in a
reasonable span of time. Indeed, he went so far as to condemn such experimentation
and suggested that we need some sort of guiding light to govern our choices
of what tests to perform. Some there
are indeed who have committed themselves to the waves of experience, and
almost turned mechanics; yet these again have in their very experiments
pursued a kind of wandering inquiry, without any regular system of
operations. And besides they have
mostly proposed to themselves certain petty tasks, taking it for a great
matter to work out some single discovery; — a course of proceeding at once
poor in aim and unskillful in design. For no man can rightly and successfully
investigate the nature of anything in the thing itself; let him vary his
experiments as laboriously as he will, he never comes to a resting-place, but
still finds something to seek beyond.
And there is another thing to be remembered; namely, that all industry
in experimenting has begun with proposing to itself certain definite works to
be accomplished, and has pursued them with premature and unseasonable
eagerness; it has sought, I say, experiments of Fruit, not experiments of
Light; not imitating the divine procedure, which in its first day’s work
created light only and assigned to it one entire day; on which day it
produced no material work, but proceeded to that on the days following. [Works
IV, p.17] Unfortunately, in this
passage Bacon gave no indication of what he took the “light” that might guide
us in our experiments to be. However,
elsewhere, he suggested that, after conducting the right sequence of experiments,
we might be able to get enough evidence to justify an inductive inference
about the “latent constitution” that gives things their “forms” and their
active and passive potencies to transmit or take on forms, as well as the
“latent processes” whereby “actives” work on “passives” to change their
forms. Indeed, he speculated that the
“latent constitutions” of things might often or even always turn out to
consist of an arrangement of differently shaped and moving but otherwise
homogeneous particles, and that the “latent processes” might often or even
always turn out to consist of mechanical interactions whereby the parts of
one object alter the arrangement of the parts of another object as a result
of motion and collision. And, just as
it is possible to tell how a mechanical device like a clock or a printing
press will work just by looking at it and seeing how, through pushing and
pulling of one part by another, the originally impressed collision leads the
machine to move to produce the effect, so it would be possible to see the
mechanism whereby actives bring about change in passives. Supposing we could develop fine enough
instruments, it would become possible to modify the parts and the motions of
“actives” and “passives” so that they would interact as we want in
collision. And we could identify
materials that could be known in advance (or “a priori,” to use a common expression for what can be known in
advance of waiting to see it happen) to perform in a certain way were they
combined. However, the
mechanical hypothesis was just a hypothesis.
In Bacon’s day, and for a long time afterward no one was able to peer
into the insensibly small parts of matter and say for sure what makes
“actives” work on “passives” as they do.
Bacon himself proposed a series of experiments that he thought would
suffice to prove the point for certain special cases, like the causes of
heat. But a few successes of this sort
were nothing more than a few successes.
People had to be convinced that the mechanical hypothesis offered a
more likely or more promising account of the workings of all actives and
passives than the old, Aristotelian hylemorphic
account. This is the job that Robert
Boyle took on in the reading. QUESTIONS ON THE
1. In what way
is Boyle’s corpuscularianism unlike the atomism of Epicurus and Lucretius?
2. What is the
cause of all change in the created world, according to Boyle?
3. What are
the two grand principles of the corpuscular or mechanical philosophy?
4. What are
the possible effects of one part of matter on another as Boyle envisioned
them?
5. What are
the properties of the parts of matter?
6. How many
different kinds of matter are there, for Boyle?
7. Why did
Boyle consider the fact that the parts of matter may be infinitely varied in
motion and shape to be an advantage?
8. What is
wrong with supposing that mechanical principles apply only to medium sized or
large objects (like clocks or heavenly bodies) but not to the small parts of
things?
9. Why did
Boyle consider that the principles and explanations of the mechanical philosophy
are clearer than those of the Aristotelians or other chemists? 10.
What is required for one part of matter to be
able to act upon another? 11.
In what sense may the mechanical philosophy coexist
with the supposition that change in nature is brought about by the agency of
spirits? NOTES ON THE
In presenting his
case, Boyle was first careful to articulate a version of the mechanical
philosophy that is explicitly compatible with the belief in the existence of
a God who created the world. The
seventeenth century was a profoundly religious time, and Boyle himself was a
profoundly religious man. But
Epicurus, the leading proponent of ancient atomism, to which the mechanical
philosophy was closely allied, had denied the immortality of the soul,
insisted that worlds evolve and decay like vegetables, and claimed that Gods
are material beings who have no concern with human affairs and who could not
intervene in the course of nature without losing their immortality. No Christian of the time could accept such
views, and Boyle began by distancing his version of the mechanical philosophy
from them. The mechanical philosophy
he meant to endorse is one that holds that it would be impossible for a world
fit for human habitation to evolve on its own — much less for human beings or
other animals to evolve on their own.
A world like ours could not arise from a chance collision of
particles, but must have been designed by a supremely intelligent being. It also must have been planted with the
seeds and eggs of all living things.
However, having once arranged the parts of the world in an appropriate
form, instituted certain laws of motion and collision, and fertilized the
earth with embryonic life forms, God does nothing more than constantly uphold
the laws of motion.
The world is like a well-designed machine, that runs on its own after
having once been set up and placed in motion, and it is so well designed that
no further intervention is necessary in order to ensure that everything
unfolds as it should. To suppose
anything else would be an insult to the skill and intelligence of the Divine
creator of the machine. Thus, after the
creation, all the phenomena of nature are, as Boyle put it, “physically
produced by the mechanical properties of the parts of matter.” We need to consider what he meant by
“physically produced,” and by “mechanical properties.” On Boyle’s account,
the mechanical philosophy involves just two basic explanatory concepts:
matter, and motion. It is worth
stressing that these constitute just two concepts. Were there different kinds of matter (e.g.,
earth, wood, salt, sulphur, gold, iron, and so on), then there would not just
be two basic explanatory concepts.
There would be more than two, as many more as there are fundamentally
different kinds of matter. The mechanical
properties of matter derive from these two basic explanatory concepts. Motion is either fast or slow and is always
directed in a certain way. It is
linear, curvilinear, spiral, rotating, oscillating, or vibrating. When matter is put into motion it either
all moves in the same way or different parts move in different ways. The effect of different parts moving in
different ways is the separation of matter into particles of a determinate
size and shape and state of motion.
These particles may be knitted or interlocked so that they form compounds
consisting of particles of various shapes and sizes and states of motion
arranged in a certain order, giving a particular “texture” to the compound as
a whole. Thus velocity, shape, size,
and (in compound parts) texture constitute the “mechanical properties” of the
parts of matter. By “physical
production” Boyle meant transmission of motion on impact. The effect of the impact of one body on
another is to pull that other after it, or push it on ahead of it, or break
it into parts that explode out in various directions, or alter the internal
arrangement or state of vibration of the impacted parts. To say that all the
phenomena of nature are physically produced by the mechanical properties of
the parts of matter is therefore to say that everything that happens in
nature happens because of the way that differently shaped and moving but
otherwise homogeneous parts are moving and banging into one another. Besides describing
what the mechanical philosophy maintains, Boyle
attempted to convince his readers that the mechanical philosophy is superior
to its rivals. To this end, he made
the following claims: 1. Clarity
and intelligibility. The
mechanical philosophy is easy to understand.
Everyone can make sense of the notions of shape and velocity and the
communication of motion as a result of collision. In contrast, the Aristotelian and
alchemical explanatory principles and basic properties are unfamiliar and
difficult to understand. There is
nothing occult or hidden about the mechanical philosophy. A mechanical account makes it clear exactly
how it is that one thing works upon another to bring about a change by
showing us the machine that produces the effect (that is, the chain of
transmission of impacts among shaped and moving parts that connects the
motion brought in by the cause with the observed effect). The Aristotelian and alchemical
philosophies, in contrast, leave the mechanism in “actives” that is
responsible for bringing about the change in the form of “passives” hidden
and unexplained and as a result they never get beyond treating change in
nature as an ultimately magical effect.
2. Simplicity. The mechanical philosophy invokes fewer
basic explanatory concepts. As noted
above, it invokes just two basic concepts, matter and motion. Moreover, these notions are fundamental. They are not based on anything else. Instead all other things are (presumably)
based on them. The chemical or
alchemical philosophy, in contrast, postulated three (salt, sulphur, mercury)
as well as a number of “occult” active principles (called “occult” because it
is not clear what makes them work as they are supposed to), and it remained
unclear to the chemists whether there might not be yet more fundamental
components making up salt, sulphur, and mercury. The Aristotelian philosophy invoked form,
matter, privation, substance, substratum, essence, action, potency, and final
causes or purposes, to name just a few. 3. Explanatory
power. Despite having so few basic
explanatory concepts and principles the mechanical philosophy is able to
account for the widest range of different phenomena. The Aristotelians, for example, invoke a
different form to account for each different kind of change. But on the mechanical account, the same thing
is going on in all change: one object is hitting another. This should strike any
student of Bacon as a surprising list of reasons for recommending the
mechanical philosophy. Recall that
Bacon insisted that a theory ought to be justified by induction from the
evidence and not by appeal to idols of the understanding. But the reasons Boyle invoked for accepting
the mechanical philosophy are blatant appeals to the idols. To recommend a theory because it is simple
is to appeal to an idol of the tribe.
We have no reason to think a priori (that is, in advance of actually
proving by induction from extensive experimentation) that nature is simple in
its operations, so the simplicity of a theory cannot justly be cited as a
reason for accepting it. The same can
be said for intelligibility and explanatory power. These are features that make a theory
easier for us to understand. But just
because a theory is easy for us to understand that does not mean that it is
correct. For a good Baconian, only an induction from the experiments can
demonstrate the correctness of a theory.
And to recommend a theory because it allows us to deduce the effect
from the cause is to worship an idol of the theatre. While it is a fine thing to be able to
deduce the effect from the cause, to accept an account of the cause simply
because it allows us to readily deduce the effect is to base one’s theory
choice on wishful thinking. We ought
to have some experimentally well-founded evidence to think that the cause is
in fact constituted that way before making such a leap. Yet, as unBaconian as Boyle’s defence of the mechanical
philosophy may be, Boyle was a great admirer of Bacon and a serious student
of Bacon’s works while Bacon, for his part, was very attracted to mechanical
accounts of “latent constitutions” and “latent processes.” If pressed, both thinkers would probably
have said that they regarded the mechanical philosophy as a “hypothesis”
rather than as a fact, that is, as a speculation about the “latent
constitutions” of materials and the “latent processes” governing all change
in nature. They might further have
remarked that they took the mechanical hypothesis to be an especially
promising one, that is, one well worth investigating further, and Boyle might
have said that appeals to its simplicity, intelligibility, comprehensiveness,
and explanatory power are just reasons for investigating it further, not
reasons for accepting it. After all,
it seems a wise policy to focus our investigations to make sure that the
simpler theories are not viable before looking at more complicated ones. But Boyle would probably have said
something more as well, though it is only imperfectly and incompletely
alluded to in the reading selection:
He would probably have said that the mechanical philosophy is tolerably well justified by
induction from the evidence. He would have had two
main reasons for saying this. One was
the development of microscopy. People
had begun grinding lenses and when they used them to magnify their view of
apparently homogeneous things, like wood and water,
they discovered these things to be made up of a complex assembly of often
moving parts. This seemed to be direct
proof of the existence of tiny, previously invisible machines inside the
parts of macroscopic objects. Boyle’s second reason
(one more explicitly alluded to in the text) has to do with the success of
late Medieval, Renaissance, and 17th century technologists at constructing
mechanical devices that could tell time, print books, raise weights up from
the bottoms of mines, power huge bellows in smelters, and so on. Appealing to this success as evidence that
change in the macroscopic world is brought about by mechanical means, Boyle
claimed that it would be extraordinary if, as we descended to the microscopic
level, we suddenly reached a point where change begins to be produced by other
principles. After all, the laws of
motion and collision do not appear to change as we move from a consideration
of larger to smaller machines. The
same principles that govern the operation of a huge mill are operative in the
tiniest clock that our craft currently allows us to forge. Experience itself, therefore, gives us no
warrant for supposing that, when we get down to a certain degree of
smallness, change ceases to be produced by collision of shaped, moving parts,
and instead starts to be produced by other means. We have to wonder
about how good a justification this was.
Quite aside from the Baconian objection that
we have no reason to suppose, a priori, that the laws that nature follows at
the macroscopic scale are analogous to those followed at the microscopic (to
appeal to analogy is to invoke another “idol of the tribe”), it is the case
that even at the large and middle scale not all phenomena are obviously
mechanical in nature. Think of burning, rusting, exploding and other chemical
reactions, or of animal motion, vegetable growth and decay, gravitation and
magnetism, emission of light and other forms of radiation, electrical
discharges in lightening and static or the nuclear fusion happening in the
sun. None of these are obviously
produced by moving parts hitting one another. Moreover, these are the things
that power machines. No machine runs
simply on its own. All seem to
ultimately have their power train initially moved by something that is not
obviously mechanical, be that thing human or animal motion (as we know today,
a product of chemical reaction rather than transmission of motion upon
contact), the falling of weights or of water (due to a force of gravitation),
the unwinding of springs (due to an apparent desire or endeavour of bent
materials to return to their original shape), the blowing of winds
(ultimately due to solar heating and hence to the causes of the burning of
the sun), the expansion of gasses (another chemical reaction), and so on.
Illustrations by Albrecht Dürer in Agricola’s De re metallica.
Note how in both illustrations the moving force (the man turning the
crank on the left and the horse on the right) are all but cut out of the
picture. Even worse, the parts of
machines are not obviously mechanical in nature. Archimedes had said that given a lever long
enough and a fulcrum on which to put it he could move the Earth. But this is false. There is no known material that such a
lever could be made of. A lever long
enough to move the earth would either bend or break when pulled upon, or it
would have to be so thick and massive that it would collapse under its own
weight or be impossible to move simply because of its own weight. A clockwork system of gears substituted for
the lever would have so many parts that just overcoming the friction between
the parts to get the thing moving would be impossible, and the force required
would strip the teeth off the gears. In
claiming to be able to move the Earth with a lever, Archimedes had been
thinking like the idealistic mathematician he was and failing to take account
of what has been called “the refractory character of matter.” The materials in nature are not ideally
light and rigid and frictionless, but heavy, malleable, ductile, brittle, sticky,
and so on. An engineer has to take
account of these facts when designing a machine, and
it becomes a challenge to find a material that is both light and strong
enough to work. But features of
materials such as ductility, hardness, brittleness, softness, viscosity,
elasticity and so on are not obviously mechanical in nature. Indeed, it is
very difficult to explain such features purely mechanically. Hardness is a good case in point. We could not say that the reason that
certain materials are hard is that they are made of interlocked, hook-shaped
parts that resist being moved relative to one another. This would simply beg the question. If the hook shaped-particles are not
themselves hard to begin with, they would bend or separate and nothing would
hold together. Despite these
difficulties, Boyle and other mechanists were unwilling to give up on the
mechanical hypothesis. They hoped
that, even though it was not then obvious that all or even most phenomena are
mechanically produced, further research would uncover more convincing
evidence in favour of this hypothesis, and they sought to do that
research. Boyle himself, for example,
is famous for his attempt to come up with a mechanistic account of the
“spring” of air (its tendency to return to a certain volume after
compression). Rejecting the
Aristotelian view that the air endeavours to sustain a certain form, he
accounted for “spring” as a consequence of the collision and rebound of
particles of air enclosed in a volume and was led to discover the law of the
relation between pressure and heating (which he reduced to the speed of
motion of particles) as a consequence.
He also did work on the spring of metals, noting that materials that
could previously be bent into any of a number of shapes could be made springy
by pounding. Since pounding is an
operation that can only plausibly be supposed to alter the arrangement of the
parts constituting the material, this seemed to be good inductive evidence
for the conclusion that spring must somehow be a result of the manner in
which the parts of bodies are arranged.
These successful
mechanical explanations of apparently non-mechanical phenomena made Boyle and
other mechanists optimistic that mechanical explanations could eventually be
discovered for everything. Even
recalcitrant phenomena like gravitation, cohesion, and hardness might, they
speculated, be accounted for as consequences of the pressure of a surrounding ether.
Nonetheless, for Boyle
and the other mechanists, a conviction, or at least a hope in the truth of
the mechanical hypothesis preceded a consideration of the evidence in favour
of that hypothesis. Indeed, a
consideration of what sort of experiments are required to justify the
mechanical hypothesis, or to discriminate between rival mechanical
explanations, seems to have been the guiding light that led them to undertake
the sort of researches that they did, and this sits uneasily with the Baconian injunction to develop grand theories only as a
consequence of a study of the evidence, and to pay particular attention to
contrary instances. For Boyle and the
mechanists an antecedent commitment to the hypothesis directed the direction
of research; the results of research did not lead to the formulation of a
hypothesis. The ideals of an inductivist, “bottom-up” scientific methodology that
dictates starting with experience and developing theories only as warranted,
coexisted with an a prioristic, “top-down”
methodology that started off with a commitment, however hypothetical, to a
particular theory. Both Boyle and
Bacon were attracted to mechanistic deductivism on
the one hand and the ideals of an inductivist
scientific methodology on the other (though Boyle is perhaps more attracted
to the former and Bacon to the latter), and their work contains interesting
internal tensions as a result. Other
early modern figures were more emphatic in their commitment to one side or
the other, and their disagreements eventually forged a split between two
opposed directions in epistemology and scientific methodology: the empiricist
and the rationalist. ESSAY QUESTIONS AND RESEARCH PROJECTS
1. Consult a
number of recent histories of technology and invention to ascertain what were
the main technological innovations and inventions to be discovered in the
sixteenth and seventeenth centuries.
Attempt to determine what led to these discoveries. Were the chief inventions and innovations
mechanical in nature (i.e., did they involve the invention of new types of
mechanical devices) or were they chemical or biological (e.g. smelting of new
alloys, breeding of new species, development of new agricultural
techniques)? Did the inventor deduce
how to build the device or make the technological innovation ahead of time,
by applying some general theory (e.g. of mechanics) to the problem and only
subsequently test to see if the device would work; was the invention or
innovation designed only through a long process of trial and error; or was
the invention or innovation the product of happenstance? Does your research support the claim, made
at the outset of this chapter, that interest in and acceptance of the
mechanical philosophy was spurred by the type of technological advances made
in the 16th and 17th centuries?
2. Boyle held
Bacon in high esteem, yet many of the reasons he offers for accepting the
corpuscular or mechanical philosophy make what Bacon ought consistently to
have condemned as an appeal to idols of the tribe and idols of the theatre,
and in other works he makes remarks that might be interpreted as saying that
he took the mechanical philosophy to be merely a hypothesis that had not yet
been adequately confirmed by the evidence.
This has led many scholars to question the extent of Boyle’s
commitment to the corpuscular or mechanical philosophy. In a classic paper, “Newton, Boyle, and the
Problem of ‘Transdiction’,” (in his Philosophy, Science, and Sense Perception
[Baltimore: Johns Hopkins Press, 1964], 61-117, esp. 88-112) Maurice Mandelbaum responded to these scholars by arguing that
Boyle was able to reconcile a commitment to the corpuscular or mechanical
philosophy with a fundamentally Baconian position
on the need to justify a theory by induction from experience. Focusing on a reading of pp. 99-112 of Mandelbaum’s paper, reconstruct his position in your own
words. If you find his position to be
unclear or unpersuasive on certain points, say so and explain why.
3. Undertake
as extensive a survey of Boyle’s works as possible and attempt to answer the
following questions as best you can in the light of that survey: To what extent was Boyle committed to the
truth of the mechanical hypothesis?
Might his degree of commitment to that hypothesis have changed over
time? If he was committed to it to any
degree, what was the ground of his commitment to it? Be explicit about the influence (or lack of
influence) of the following factors on his thought: the development of
microscopy; the mechanistic (or non-mechanistic) character of important
technological innovations and inventions of his time; the extent to which it
really seemed to Boyle that all the phenomena of nature could be accounted
for mechanistically, including such recalcitrant phenomena as gravitation,
hardness, and cohesion.
4. Determine
to what extent a concern to justify a mechanical account of the spring of air
was foundational for Boyle’s discoveries about the relation between the
pressure, volume and temperature of a gas. |
