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7 Descartes, Discourse on method I-II and V (AT VI 1-22
and 55-60)
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Descartes, Discourse on method II Early modern philosophy
was profoundly influenced by developments in two other areas: natural science
and religion. These two influences did
not sit easily with one another. The early modern
period was a deeply religious era, and in France and Great Britain, the main
centers of early modern philosophy, religion took one or the other of two
forms: the external, ceremonial, and hierarchically governed religion of the
Roman Catholics, dominant in France, and the internal, enthusiastic, and
republican religion of the Reformed Church with its Puritan and Presbyterian
offshoots, dominant in England and Scotland.
These two forms of religion had been at war since the time of the
Protestant reformation. However, both
forms of religion were committed to certain fundamental Christian doctrines:
God’s role as not merely designer, but creator of the very stuff the universe
is made of, and the necessity of belief in the risen Christ for salvation and
in Christ’s status as the second person of the Trinity. Neither form of early
modern religion sat well with the mechanistic tendencies of early modern
science. The tension is nowhere as
explicit as it is in the mechanistic philosophy of Hobbes. As has been seen, Hobbes maintained that
human beings are simply machines, he denied the existence of immaterial
spirits and of the freedom of the will, and he had a conception of the Divine
nature that seemed pious only to the extent that it refrained from saying
anything about the nature God, though it seemed to hint that God has to be a
material being. As a result, Hobbes
was widely denounced as an atheist and a libertine, who suggested God is a
material thing, questioned the justice of punishing the wicked in an
afterlife (when there could be no reformative or deterrent justification for
the punishment), and held that there is no need to observe moral rules when
there is little chance of being caught and punished. Hobbes was nonetheless
able to live to a very old age without suffering persecution or more than
temporary and limited censorship of his works. There are a couple of reasons for
this. First, he was very careful not
to go too far. Second, he lived most
of his life in a Protestant country.
The enthusiastic form of the Protestant religion, which emphasized an
ecstatic personal union of the individual with God, pushed the Protestants in
the direction of rejecting ecclesiastical and civil hierarchies, viewing each
person’s religion as their own affair, and consequently instituting a broad
religious toleration and a degree of freedom of the press. This worked in Hobbes’ favour. However Hobbes was also concerned to insist
on his Christianity, and was at pains to demonstrate that nothing in his work
is actually in conflict with scripture.
He may have implied that God is material, but he never said it; in
fact he denied it, and that is what would have counted had he ever been
summoned into court on charges of heresy or atheism. And while he did maintain that our souls
are material and decay along with the body, this was not clearly
unorthodox. The Christian church had
always stressed the resurrection of the body at the final judgment, so Hobbes
could claim that it is not necessary to suppose the existence of an immortal,
spiritual soul in order to believe in an afterlife. And, as already noted, he could point out
that nothing in scripture entails that angels or devils have to be spiritual
in nature. Even Hobbes’
determinism — his denial of the freedom of the will — was not clearly
unorthodox in a Protestant country.
Calvinist Protestantism was itself deterministic and the Calvinist
Puritans and Presbyterians in While Hobbes was able
to avoid persecution and serious censorship, he did not have an entirely easy
time. His philosophy was widely
perceived as opening the door to more radical free-thinkers, who would build
on his work to deny the existence of God and an afterlife. At one point during his lifetime there was
a move in Parliament to launch a formal inquiry into the orthodoxy of his
views on religion, and shortly after his death two of his works, including Leviathan, were formally condemned and
burned at
Galileo’s Recantation
of the views of Copernicus Not surprisingly, many
champions of the new philosophy were anxious to deny any intention of offering
a “reform.” At the outset of his Discourse on method, Hobbes’ French
contemporary, René Descartes, wrote: “I could in no way approve of those
troublemaking and restless personalities who, called neither by their birth
nor by their fortune to manage public affairs, are forever coming up with an
idea for some new reform in this matter.
And if I thought there were in this writing the slightest thing by
means of which one might suspect me of such folly, I would be very sorry to
permit its publication.” His protestations to
the contrary notwithstanding, Descartes did mean to propose a reform in
natural philosophy. But, though this
is what he meant to do, he was reluctant admit it. It is not just that he was afraid, though
he had good reason to be. As many of
his comments in correspondence with his friends make clear, he also believed
that flying in the face of people’s prejudices is no way to make
progress. It simply incites them to
reject and suppress your work, and you end up achieving nothing. It is much wiser, Descartes thought, to
proceed in a more devious fashion: Try
to convince the authorities that the principles you are advocating do not
touch on established beliefs — or that if they do they serve to support them
by setting them forth in the light of a new method of presentation. Then, once you have convinced them to
accept your apparently innocent first principles, you can leave it to them to
draw the conclusions that necessarily follow from these principles. Here, for example, is what Descartes wrote
to Mersenne on the eve of the publication of his Meditations on first philosophy: and I can tell you that these
six Meditations contain all the fundamentals of my physics. But this should not be broadcast, please,
because those who favour Aristotle might then have difficulty in approving of
them, whereas I hope all who read them will become insensibly accustomed to
my principles and recognize the truth of them before they discover that they
destroy the principles of Aristotle.
Sir, I have had here all
afternoon a distinguished visitor, M. Alphonse, who discussed the Descartes had only
been impelled to write what he did because, he claimed, of a sceptical
crisis. In the early years of the
Protestant reformation, Catholics had attacked the Protestant rejection of an
ecclesiastical hierarchy by resurrecting sceptical arguments that showed the
inadequacy of all our knowing powers and the consequent inability of any
individual to discern the Word of God simply from a personal engagement with
scripture, unassisted by traditional and divinely sanctioned authority. However, the sceptical arguments were so
powerful that they proved a double-edged sword, allowing Protestants to
retort that the sceptical arguments applied as well to Bishops and Popes as
people, and that no one unassisted by a direct infusion of Grace and born
again in the Word could overcome the natural weakness of the human knowing
powers. In the end, the only winners
had been atheists and libertines, who wanted to cast all belief and all
religion into doubt. Descartes
presented himself as someone who had found a way to reply to the sceptics. However, the challenge
facing mechanical philosophers in Catholic countries was not just how to
replace Aristotelianism without looking like reformers, but how to justify
replacing it with an alternative as apparently irreligious as the mechanical
philosophy. The Churchmen in Because the church in
Catholic countries was still too powerful, and too authoritarian to be
effectively resisted, those who wanted to advocate mechanistic natural
philosophy had only one choice: to seek for some form of accommodation — to
do for Democritus and Epicurus what Thomas Aquinas had done for Aristotle:
reinterpret their philosophy in such a way as to make it acceptable to
Christians. Descartes was the prime
architect of this accommodation. The
sub-title of the second edition of his most famous work, the Meditations, “in which the existence
of God and the distinction of the human soul from the body is demonstrated,”
clearly indicates the direction Descartes wanted his project to take. He was out to write a
Title
pages of the first and second Latin editions of Descartes Meditations. The
subtitles changed between the two editions.
Whereas in the first Descartes claimed to demonstrate the existence of
God and the immortality of the soul, in the second he instead claimed to
demonstrate the existence of God and the distinction of the soul from the
body. The revised claim is the correct
one. philosophy that would
establish the foundations for a mechanistic science of nature and his Meditations were directed to lay the
groundwork for such a science by showing: •
that all that really exists in the physical
world are extended particles in motion, •
that there are no real qualities of hardness,
ductility, and the like inhering in bodies and distinguishing matter into
different kinds or elements, •
that sensible qualities are merely feelings in
us, and •
that the proper
way to gain knowledge is not by a method of observation and experiment
relying upon the senses but by the use of pure reasoning. But you would not learn any of this from reading the title
page of the Meditations. It is instead advertised as an attempt to
prove the existence of God and the distinction of the soul from the body. In billing his work in
this way, Descartes was not simply being devious. In the Meditations
he offered repeated demonstrations of the existence of God, and while he
never actually got so far as to prove the immortality of the soul, he did try
to establish that human beings have spiritual souls, and are not just
bodies. Christian believers of all
types were confronting a sceptical crisis, due not so much to attacks by
atheists but to their own mutually destructive employment of sceptical
arguments against one another. New
arguments to support the old beliefs were needed. Descartes doubtless hoped to profit by this
situation and insinuate the mechanistic philosophy at the same time as he
performed the service of setting religious belief beyond sceptical attack. Neither should we
think that Descartes’s attempts to prove the
existence of God and the distinction of the soul from the body were purely
opportunistic. As he made clear in Discourse V, there are excellent
reasons for taking human nature to be non-mechanical in its operations: the
human reasoning power is, as he put it there, a “universal instrument,” that
is, it is versatile and able to figure out how to deal with novel
difficulties. It can learn from its
mistakes and it can discover universal principles from which it can calculate
in advance how best to approach problems.
A machine, in contrast, particularly a machine of the type Descartes
and other early modern philosophers were familiar with (a mechanical device)
can only do the particular task it was designed to do. Adapting it to perform
multiple tasks requires introducing new design elements, a new element for
each task, and the machine rapidly becomes too complex and unwieldy. Moreover, it is only through introducing new
design elements ahead of time that the machine can be made to perform
different tasks. It remains able to do
only what it was previously designed to do and lacks the ability to figure
out how to deal with novel situations. The non-mechanical
components of human reasoning are particularly evident in speech, where we
seem to be confronted with an infinite number of tasks — answering questions,
describing experiences, giving instructions, recalling events, and on and
on. Descartes believed that it is simply
impossible for any machine to be adequately designed to perform these tasks,
so that the use of language serves as a powerful indication of the ability to
respond spontaneously to unanticipated and novel circumstances, an ability
that, Descartes supposed, cannot be explained mechanically. (It is no objection, therefore, that
machines might be designed to make noises resembling human speech. Such machines would have to be designed to
make certain noises in response to certain stimuli, and while they might
momentarily trick us into thinking they are rational we would soon learn that
they always respond in the same way to the same sort of stimulus, and that
would show to us that they are not reasoning but merely responding.) However, Descartes
seems to have thought that the use of speech serves as more than just a
particularly effective demonstration of our possession of a non-mechanical
reasoning ability. He supposed that
our use of speech shows, in addition, an ability to grasp the sense or
meaning of what has been said to us, and provides us with a way to
communicate the sense or meanings that we have grasped to others. We are able to “respond to the sense” of
what is said, as he put it. This is
something that exceeds the power of any mechanical device. All that a mechanical device can do is
move. If it is hit or its parts are
hit, those parts can move in ways that, say, compress a bellows and cause a
sound to be emitted, or turn the drum of a player-piano and cause a musical
score to be played. But we do not
think that in addition to performing these motions the machine does something
else that we would call grasping the meaning or the significance of what has
happened. If the bellows is compressed
and the sound is emitted we do not think that this is because the machine has
felt pain or understood that someone is saying something false and is wanting
to object to the error. We simply
think that it is moving in a certain way in response to stimuli. But we ourselves are aware of more than
that. We do not just feel our sense
organs, nerves, and brain moving in different ways. We feel pain or pleasure, see colours, and
grasp the meaning of signs. When we
use language we use it to communicate these thoughts, feelings, and
intentions to others. And when we hear
others using language, it is hard for us to think that it is merely a
programmed response made by a machine.
We rather think that it is indicative that they are experiencing
sensations and thoughts and meanings in the way that we do, and that they are
communicating these experiences to us. In previous lectures,
I noted that the lived qualities of our experience, our feelings and
sensations, pose a serious problem for a mechanist like Hobbes, who thinks
that nothing exists inside of us except motions of particles. We know from our personal, lived experience
that there is more to the world than that.
Colours, tastes, and pains also exist.
But where do they exist, and how?
If the external world consists just of shaped particles in motion, and
we ourselves are no more than that, then there is no obvious answer to this
question because it is unclear how any arrangement or motion of shaped
particles could constitute a colour, taste or pain. Unlike Hobbes, Descartes had an answer for
this question. Like Hobbes, he
supposed that we human beings have bodies that operate in purely mechanical
ways. But unlike Hobbes, he supposed
that there is something more to us. In
addition to bodies we also possess minds.
Motions and arrangements of shaped particles in our bodies cause our
minds to feel certain things and to experience certain sensations, feelings
that are unlike any motion or arrangement of shaped particles and sensations
that have qualities that are not reducible to shape and motion. For Descartes the
supposition that we human beings have minds was therefore not just a counsel
of policy. It was an inescapable
conclusion from the evidence that human nature and particularly the human
reasoning and speaking abilities are intractable mechanically. And it was the
product of an inference to the best explanation for the felt qualities of
experience. Something has to be
responsible for these things, and, if it is not a machine, then it might well
be a immortal soul or spirit. And if he could tag on the claim that the
soul or spirit is “immortal” all the better. (Descartes did this on the title page of
the first edition of his Meditations,
though when it was pointed out that he had actually failed to anywhere
demonstrate that the soul is immortal, he modified the title to claim, more
modestly, just that he had established that we must have souls that are
radically unlike our bodies.) Descartes saw this as
the key to reconciling religion and mechanistic natural philosophy. We could split the world into two parts: a
realm of immaterial minds or souls, angels, and God, and a realm of extended
particles in motion. Religion could
describe the former world, where the rules of ethics and commands of God are
the only laws, and natural philosophy could describe the natural world, where
the laws of motion and collision are operative. The two worlds could peaceably coexist,
each running in their own separate ways, but they would also meet within the
human being, who is a unique and special union of the two distinct
substances: extended, moving matter and thinking, sensing, willing mind, the
mind receiving its sensations as a result of “observing” motions set up in
the brain as a consequence of the body’s being hit by flying particles, and
the body in turn being moved not only by impacts from without, but by
commands of the mind within. Christian theology had
an impact on the development of Descartes’s
philosophy at this point. If it is the
soul that senses and feels and grasps the significance of signs, and, as a
matter of Christian doctrine, only human beings have souls, then it follows
that non-human animals must not really be sentient or intelligent, even at a
rudimentary level. They must simply be
machines. This seems
counter-intuitive, but Descartes bit the bullet on the matter and maintained,
with the Christians, that the ancient tradition ascribing souls of varying
capacities to all living things, even plants, is mistaken. Descartes insisted that it is evident that
animals have no speaking or reasoning ability whatsoever, but merely
instincts implanted in them by nature (that is, by the way the machine of the
animal body was designed). Thus,
animal cries and even the speech of parrots are just noises that the animal
body makes in response to set stimuli, and any abilities animals may have to
solve problems better than we do are indicative of a lack, rather than a
presence of reasoning ability. This is
because reason is a universal instrument, which entails that the more you
have of it, the better you ought to be able to perform at all tasks
whatsoever. If animals only perform
some tasks better than we do, but not all, that is an indication that they
are not exceeding us because of superior reasoning ability, which would have
to imply a general superiority, were it to exist. They must rather be acting simply out of
instinct, which is nothing more that a feature of the mechanical design of
the animal body. QUESTIONS ON THE
1. From what
does the diversity of our opinions arise?
2. What are
the sciences of mathematics and philosophy good for?
3. What was
the chief cause of Descartes’s delight with
mathematics and his dismay with philosophy?
4. After
abandoning the study of letters, what two sources did Descartes turn to in
the search for knowledge?
5. What led
him to subsequently reject one of these two sources as well?
6. What excuse
did he offer for proposing an innovation in scientific method, despite the
danger that it might be perceived as reformist?
7. What are
the disciplines that Descartes thought most likely to be able to contribute
to his plan?
8. In what way
does geometry serve as a model for all the things that can fall within human
knowledge?
9. Why was it
so important to Descartes that he begin his investigations with absolutely
certain and indubitable truths? (This
is the first of his four rules of method). 10.
Could we distinguish between machines that
have been perfectly made to look and behave like animals and real animals? 11.
What are the means by which we can distinguish
between machines that look like human beings and real human beings? NOTES ON THE
Descartes prefaced his
three essays with a little essay on method, the Discourse on method. Discourse
I opens with a joke about the distribution of good
sense, which must of all things be the most equitably distributed because no
one can be found who would confess that they did not get their fair
share. But the joke leads to a couple
of serious points. Descartes meant to
suggest that we probably really are all endowed with an equal measure of good
sense. Therefore, there is no one who
has the right to set themselves up as a superior authority to everyone else
in this matter, and dictate what others should think. Moreover, if people do appear to be stupid,
it is not because they are lacking in good sense, but because they are
lacking in something else: method — the ability to apply their good sense in
the right way. Descartes claimed to
have come up with the right method for gaining knowledge, and in the Discourse he described it. By his own confession
over the autobiographical remarks he made in Discourse I and II, Descartes had quickly become disgusted with
the education he had received. He had,
however, retained a degree of respect for three disciplines: logic, geometry,
and algebra. While Descartes thought that there are problems with each of these
disciplines considered individually (logic does not help us discover new
things, geometry exhausts the imagination, algebra
exhausts the intellect), he also thought that there must be something
fundamentally correct about all of them, since they are so successful. What is more, if we keep in mind the point
of the opening joke (that what makes one person, and by implication one
science, smarter than another is not more good sense, but a better method),
then this success in logic, geometry and algebra probably has something to do
with their method. Thinking about this,
Descartes noticed that the same method is employed in all three
sciences. Logic, geometry, and algebra
are all deductive sciences. They
proceed by deriving more difficult or complex propositions from certain
initial definitions, axioms, and postulates assumed at the outset. Realizing this, Descartes proposed to make
some “essays” (trials or attempts) at applying this method within the context
of other disciplines — to the science of optics in the Dioptrics and the science of
meteorology in the Meteorology. He also attempted to apply a refined
version of the method to geometry itself in the essay on geometry. When he did so, he discovered that he was
able to make significant discoveries. This was all the evidence he needed to
convince himself that he had stumbled on the correct method for obtaining
knowledge. Descartes described
his method as involving the application of the four rules laid out towards
the end of Discourse II (AT VI 18-19). The rules recommend that we (i) start
from clear and evident first principles, (ii) determine what we can know
about the most simple things first and only then move to more complex things,
(iii) arrive at our knowledge of the more complex things by deduction
from what we know about the simples, using the axioms identified at step (i),
and (iv) make frequent reviews of our work in order to correct any
mistakes that might creep in. These rules reflect
the way work is carried out in the fields of logic, geometry, and
algebra. In all of these fields,
certain rules are assumed at the outset, and a certain universe of discourse
or set of simple elements for those rules to work upon is formally specified. In Euclidean geometry, for instance, the
rules are the rules for ruler and compass construction of geometrical
diagrams, and the elements are points, lines, planes, solids. In sentence logic the rules are an
inference rule and certain axiomatic sentences and the elements are the
sentence letters and the connectives like “and,” “or,” and “not.” Once the elements and the rules have been
specified, we go on to perform constructions or give proofs and so generate
more complex figures (in geometry) or sentences (in logic). When we do this we make frequent reviews of
the constructions and proofs to ensure that we have not made any mistakes in
the application of the rules. The same
can be said for demonstrations in algebra. The main difference
between Descartes’s method and the method of
geometry, logic, and algebra is that in geometry, logic and algebra the rules
and the simple elements that they are applied to are sometimes simply
arbitrarily stipulated or assumed to exist or to be true,
and this is not something Descartes was willing to countenance. We cannot simply assume our first
principles, even provisionally, but must know for certain that they are
true. And the simple elements cannot
be just any arbitrarily concocted things, but must be the simple elements we
commonly encounter in our thinking. For Descartes, it was
particularly important that the first principles be certainly and evidently
true, and not merely assumed. Were there any uncertainty in the first
principles, everything we derive from them would be open to question. There had been too much arbitrary system
building in the past, Descartes observed, and all that it had produced was
conflict, disputation, and uncertainty over which of many different,
arbitrarily constructed systems is the correct one. The only way to make progress is to not
even begin unless we have first assured ourselves that our fundamental
principles are impeccable. Interestingly, the
rules of Descartes’s method do not just reflect the
way researchers proceed in logic, geometry, and
algebra. They also reflect the way a
mechanic proceeds on the shop floor. A
clock maker sitting at a table in front of a pile of gears and springs and
rods is looking at a collection of simple elements that, when carefully
assembled in accord with certain rules, will build a more complex
device. Descartes’s
method is designed so that, when applied to such fields as physics and
cosmology, it will induce us to treat the parts of the natural world as so
many simple components for a mechanical device. It has a built-in tendency to suggest a
mechanical view of nature. There are two,
further, especially striking features of Descartes’s
method: the order of rules (i) and (ii), and the source to which we appeal
for our information at step (ii). Note
that when we follow the method, the first thing we are supposed to do is
discover absolutely certain first principles (what presents itself so clearly
and distinctly to the mind that there is no room to doubt it, as Descartes
put it). It is only after we have done
this that Descartes envisioned examining our ideas and breaking them down
into their simplest component parts.
This is a reversal from Hobbes’ method, where we are first supposed to
consult sensory experience in order to discover simple elements that we put
together in definitions of terms, and only then relate terms to one another
to formulate the first principles of a science. Indeed, it is more than just a reversal,
because whereas Hobbes saw us obtaining our knowledge of simple natures from sensory
experience, Descartes looked to a quite different source. This is not a point that is immediately
evident from his statement of the four methodological rules, but it is quite
clearly indicated by some remarks he made earlier on in the Discourse. In Discourse I, after recounting how he
came to be disgusted with the learning he had received while at university,
Descartes remarked that he had resolved “to search for no knowledge other
than what could be found within myself, or else in
the great book of the world.” But
towards the close of that section he confessed to feeling the same disgust
with common sense and worldly knowledge that he had formerly felt for
academic teachings. He had discovered,
upon investigation, that “there was about as much diversity [in the customs
of other people] as I had previously found in the opinions of the
philosophers” so that “as long as I merely considered the customs of other
men, I found hardly anything there about which to be confident.” This left
only one alternative. Disgusted both
with academic teachings and with common sense, he “resolved one day to study
within myself.” It is this source,
meditation upon the ideas that he found within himself that Descartes meant
to turn to at the second step of his method.
He was looking for a kind of pure intellectual knowledge, divorced as
much from everyday experience as from scholarly authority. Descartes’s proposed
method is even more fundamentally opposed to Aristotle’s and Bacon’s methods
than it is to Hobbes’. For Aristotle,
experience does not simply supply us with the raw materials for definitions,
but with the basis to go on to discover general rules by induction. For Bacon, likewise, we must proceed
inductively from experience and formulate grand theories and fundamental
principles only after careful testing.
In contrast to these methods, which go up to generalities from sense
experience, Descartes’s method is “top-down.” We formulate our fundamental principles
first, and only then apply them to experience. Thus, in the hands of Descartes, the
tension that has already been observed between the a
prioristic tendencies of the mechanical philosophy
and the inductivist and empiricist ideals of Baconian science turns into a divorce. Mechanical philosophy abandons experience
and relies exclusively on reasoning from introspectively self-evident first
principles. This raises two
questions: If we are not going to
consult experience, where do we get our first principles and our ideas of
simple natures? And how can we be sure
that they are correct? The job of Descartes’s Meditations
on first philosophy and Principles of Philosophy is to answer
these questions. ESSAY QUESTIONS AND RESEARCH PROJECTS
1. Assess the
strength of Descartes’s arguments for the existence
of a soul distinct from the body, as those arguments are laid out in Discourse V.
2. Assess the
strength of Descartes’s reasons for denying that
animals have souls.
3. Speculate
on how Hobbes would reply to Descartes’s reasons
for claiming that rational souls “can in no way be derived from the
potentiality of matter,” drawing on his account of the causes of the use of
signs and the basis for our reasoning as that account is laid out in Human nature IV-VI; De corpore
I.1-5, VI.1-6,11-18; and Leviathan IV-V.
4. Consider
which (if either) of the two, Hobbes or Descartes, had the best arguments for
his position on human nature. Was
Hobbes’ attempt to come up with a mechanical account of the workings of the
mind any more compelling than Descartes’s reasons
for claiming that there can be no such account? |
