## 1. Early Years



Descartes was born in La Haye on March 31, 1596 of Joachim Descartes
and Jeanne Brochard. He was one of a number of surviving children (two
siblings and two half-siblings). His father was a lawyer and
magistrate, which apparently left little time for family.
Descartes' mother died in May of the year following his birth,
and he, his full brother and sister, Pierre and Jeanne, were left to
be raised by their grandmother in La Haye. At around ten years of age,
in 1606, he was sent to the Jesuit college of La Fleche. He
studied there until 1614, and in 1615 entered the University of
Poitiers, where a year later he received his Baccalaureate and License
in Canon & Civil Law. For the history and the text of his thesis,
see the following supplementary document:



Descartes' Law Thesis




In 1618, at the age of twenty-two, he enlisted in the army of Prince
Maurice of Nassau. It is not known what his duties were exactly,
though Baillet suggests that he would have very likely been drawn to
what would now be called the Corps of Engineers (Baillet, Livre 1,
Chapitre 9, p. 41). This division would have engaged in applied
mathematics, designing a variety of structures and machines aimed at
protecting and assisting soldiers in battle. Sorell, on the other
hand, notes that in Breda, where Descartes was stationed, the army
"doubled as military academy for young noblemen on the
Continent" (Sorell, p. 6). And, Gaukroger notes that the
education of the young noblemen was structured around the educational
model of Lipsius (1547-1606), a highly respected Dutch political
theorist who received a Jesuit education at Cologne (Gaukroger, pp.
65-6). Although the historical records point to there being a
military presence in Breda, there is no definitive evidence that
speaks for there being a full-fledged "academy". There are
reasons for thinking that Descartes may have been a soldier, but the
majority of biographers suggest that it is more likely that his duties
were oriented more toward engineering or education.



While stationed at Breda, Descartes met Isaac Beeckman
(1588-1637). Notes that Descartes kept related to his
correspondence reveal that he and Beeckman had become more than simple
acquaintances--their relationship was more one of teacher and
student (Descartes being the latter). This relationship would rekindle
in Descartes an intense interest in the sciences. In addition to
discussions about a wide variety of topics in natural science, a
direct result of certain questions posed by Beeckman compelled
Descartes to write the *Compendium Musicae*. Among other
things, the *Compendium* attempted to work out a theory of
harmony rooted in the concepts of proportion or ratio, which (along
the lines of the ancients) attempted to express the notion of harmony
in mathematical terms. It would not be published during
Descartes' lifetime. As for Beeckman, Descartes would later
downplay his influence.


## 2. *The World* and *Discourse*



After Descartes left the army, in 1619, his whereabouts for the next
few years are unknown. Based on what he says in the *Discours de la
Methode* (*Discourse on the Method*), published in 1637,
there is speculation that he spent time near Ulm (Descartes apparently
attended the coronation of Ferdinand II in Frankfurt in 1619). There
is some evidence suggesting that he was in France in 1622, for it was
at this time that property he had inherited was sold--the
proceeds of which would provide him a simple income for many years.
There is some speculation that between 1623 and 1625 he visited Italy.
Descartes emerges in 1625 in Paris, his notes revealing that he was in
contact with Father Marin Mersenne (1588-1648), a member of the
Order of Minims. This relationship would prompt Descartes to make
public his thoughts on natural philosophy (science). It is by way of
Mersenne that Descartes' work would find its way into the hands
of some of the best minds living in Paris--for instance, Antoine
Arnauld (1612-1694), Pierre Gassendi (1592-1655), and
Thomas Hobbes (1588-1679).



In 1628 Descartes left Paris. At this time he seems to have been
working on the *Regulae ad Directionem Ingenii* (*Rules for
the Direction of the Mind*), a work that he would abandon, some
speculating around the time of the move from Paris. It is worth noting
that relatively recently a copy of the *Rules* was discovered
in a library at Cambridge University. Scholars are unsure how it got
there. Currently, based on what it includes, it is thought that this
manuscript represents the work as it stood when Descartes had
abandoned it in 1628. The later Amsterdam printing (1701) and a copy
that Leibniz acquired from Clerselier (c. 1670) make certain
advancements over what is found in the Cambridge manuscript. So, it
appears that Descartes picked up the work again. Some have speculated
that this may have happened after a visit in 1635 from John Dury
(1596-1680) and Samuel Hartlib (1600-1662), where Hartlib
reports that Dury had returned to England with copies of some of
Descartes' works (Fallon, pp. 9f); the speculation being that
the recently discovered manuscript is related to something brought
back by Dury. The meeting took place in The Hague. Dury and Hartlib
were friends of the Cambridge philosopher Henry More
(1614-1687), with whom Descartes had corresponded, and of others
in More's circle, including John Milton (1608-1674).
Perhaps the copy was made during the visit and brought back to
Cambridge. (In any event, this is a new and interesting development in
Descartes scholarship.) In 1630 Descartes moved to Amsterdam. There he
worked on drafts of the *Dioptrique* (the *Optics*) and
the *Meteors* (the *Meteorology*), which were very
likely intended to be a part of a larger work, *Le Monde*
(*The World*). In 1632 he moved again, this time to Deventer,
to apparently teach Henry Reneri (1593-1639) his physics. It is
also during his stay in Deventer that Descartes probably worked on a
final draft of the *Traite de l'homme* (*Treatise on
Man*), which in connection to the *Optics* and the
*Meteorology* was probably originally intended to be a part of
*The World*.



When *The World* had become ready for publication in 1633, upon
hearing of the Church's condemnation of Galileo
(1564-1642) in the same year, Descartes decided against its
publication. For, the world system he had adopted in the book assumed,
as did Galileo's, the heliocentric Copernican model. In a letter
to Mersenne, dated November 1633, Descartes expresses his fear that
were he to publish *The World*, the same fate that befell
Galileo would befall him. And, although this is something that he
understandably would want to avoid, some scholars question
Descartes' expressed concern, for his living in the Netherlands
would have kept him out of reach of Catholic authorities. *The
World* appears to have been constituted of several smaller, but
related, works: a treatise on physics, a treatise on mechanics
(machines), a treatise on animals, and a treatise on man. Although
much of *The World* has been lost, some of it seems to have
survived in the form of essays attached to the *Discourse*
which, as was mentioned earlier, would be published four years later,
in 1637. And, some of it was published posthumously. Arguably,
Constantijn Huygens (1596-1687) received what Descartes refers
to as "three sheets" of *The World*, along with a
letter dated 5 October 1637. These "sheets" deal primarily
with mechanics.



Around 1635, at the University of Utrecht, Reneri began teaching
"Cartesian" physics. Also during this year, a domestic
servant by the name of Helene gave birth to a baby girl, Francine.
Genevieve Rodis-Lewis claims that Francine was born 19 June 1635
(Rodis-Lewis, p. 40). According to a baptismal record, dated 28 July
1635, Descartes is named the father (AT I 395n). However, Gaukroger
claims that the baptismal date was 7 August 1635 (Gaukroger, p. 294).
In 1636 Reneri acquired an official chair in Philosophy at the
University of Utrecht, and continued to build a following of students
interested in Cartesian science. Around March of 1636, at the age of
forty, Descartes moved to Leiden to work out the publishing of the
*Discourse*. And, in 1637 it is published. With the
*Discourse* out and a following of students building in
Utrecht, Descartes seems to have turned his attention from career to
family. In a letter dated 30 August 1637 we find him apparently
working out an arrangement for Francine, but strangely refers to her
as his "niece"--which suggests that he did not want
certain people to know that he was a father (or that Francine had been
born out of wedlock). Gaukroger suggests that despite this apparent
denial of paternity, Descartes not only corresponds with Francine, but
in 1637 brings her and Helene to his new home at Santpoort or
Egmond-Binnen (Gaukroger, pp. 294, 332).



The *Discourse* is the first published work of
Descartes', coming some four years after he had abandoned
*The World*. The *Discourse* is important for many
reasons. For instance, it tells us what Descartes himself seems to
have thought of his early education, and in particular, his early
exposure to mathematics. Roger Ariew suggests that these reflections
are not so much those of the historical Descartes, as much as they are
those of a persona Descartes adopts in telling the story of the
*Discourse* (Ariew, pp. 58-63). Uncontested, however, is
the view that the *Discourse* sketches out the metaphysical
underpinnings of the Cartesian system. And, as a bonus, it has three
works that are attached to it that are apparently added so as to
exemplify the method of inquiry it develops (though admittedly it is
unclear how the method is applied in these essays). The attached
essays are the *Optics*, the *Meteorology*, and *Le
Geometrie* (the *Geometry*). As was suggested earlier, the
*Optics* and *Meteorology* were very likely versions of
works originally intended for *The World*.



It should be stressed that the three attached essays are important
independent of the *Discourse*, for they contain much worth
studying. In the *Optics*, for example, Descartes works out his
laws of refraction, and within this context, what would later be
called Snell's Law (which Descartes seems to have worked out as
early as 1632). Further, although the *Geometry* would seem to
have come out of nowhere, there is evidence in Descartes's notes
to himself, from which Clerselier reconstructed some of
Descartes's correspondence, that he had been working on some
version of it as early as 1619. In a letter to Beeckman, dated 26
March 1619, for example, Descartes discusses the subject matter that
is found in the *Geometry*, and in a letter dated 23 April
1619, he explicitly mentions the book's title. It is in this
work that Descartes shows how certain geometrical problems can be
solved by way of algebraic equations.



The significance of the sort of connection that Descartes made between
geometry and algebra was great indeed, for without it the
mathematization of the physics and the development of the calculus
might not have happened when they did--a generation later via Sir
Isaac Newton (1642-1727) and Gottfried Leibniz
(1646-1716). It should be noted, however, that as groundbreaking
as this work may have been, contrary to the claims of many, nowhere in
the *Geometry* is a "Cartesian Coordinate System"
ever developed (that is, the *x*-*y* coordinate system
taught to today's students of algebra), nor is he the originator
of other mathematical concepts that bear his name, for example, the
"Cartesian Product". Carl Boyer notes that various
concepts that lead to analytic geometry are found for the first time
in the *Geometry*, and that the *Geometry's*
mathematical notation is still used today. But, he argues, although
Cartesian geometry is taken by many to be synonymous with analytic
geometry, the fact is that the fundamental aim of Descartes'
system is quite different from that of contemporary analytic geometry
(Boyer, pp. 370-1). And so, the claim that Descartes is the
originator of analytic geometry, at least as we understand it today,
overstates the case. As Boyer rightly points out, however, this does
not diminish the importance of the work in the history of
mathematics.


## 3. The *Meditations*



In 1639 Descartes began writing the *Meditations*. And, in 1640
he returned to Leiden to help work out its publication. During the
year, Descartes' daughter, Francine, died. There is evidence
suggesting that he was called away from Leiden around the time of her
death, returning soon after. Some have speculated that he left Leiden
to be at her side. Also during this year, Descartes' father and
sister died. Descartes' relationship with his father (and
brother) was of the sort that Pierre, his brother, failed to even
bother him with the news of their father's death. Rather, it
seems to have been in a letter from Mersenne that Descartes first
learns of it. In a follow up letter to Mersenne, dated 3 December
1640, Descartes expresses regret in not having been able to see his
father before his death. But, he refuses to leave Leiden to attend his
father's funeral, and instead stays to complete the publishing
of the *Meditations*. 



Today, the *Meditations* is by far Descartes's most
popular work--though this would not have been the case in
Descartes' day. This work is important to today's scholar
for many reasons, not the least of which is its including as an
attached text written objections from some of the best minds living in
Paris. Mersenne sent the *Meditations* to philosophers and
theologians for criticism. The list of critics includes: Caterus,
Hobbes, Arnauld, Gassendi, and Mersenne himself, with several other
unnamed readers who raised their objections through Mersenne. A later
edition would include an objection from Bordin. Descartes replied to
each critic, and the result was an appended text referred to as
"The Objections and Replies." The second edition contains
seven sets in all.



The *Meditations* opens by developing skeptical questions
concerning the possibility of knowledge. Through a series of several
carefully thought out meditations, the reader establishes (along with
the author) the groundwork for the possibility of knowledge
(scientia). Descartes is not a skeptic, as some have insisted, but
uses skepticism as a vehicle to motivate his reader to
"discover" by way of philosophical investigation what
constitutes this ground. In the Second Replies, Descartes refers to
this style of presentation as the "analytic" style. There
were two styles of presentation: analytic and synthetic. It is
important not to confuse these terms with those, say, used by Kant.
For Descartes the analytic style of presentation (and inquiry)
proceeds by beginning with what is commonly taken to be known and
discovering what is necessary for such knowledge. Thus, the inquiry
moves from what is commonly known to first principles. The
"discovery" moves in such a way that each discovery is
based on what was discovered before. By contrast, the synthetic style
of presentation begins by asserting first principles and then to
determining what follows. Prompted by Mersenne, Descartes sketches out
in the Second Replies a synthetic rendering of the
*Meditations*.



In establishing the ground for science, Descartes was at the same time
overthrowing a system of natural philosophy that had been established
for centuries--a qualitative, Aristotelian physics. In a letter
to Mersenne, dated 28 January 1641, Descartes says "these six
meditations contain all the foundations of my physics. But please do
not tell people, for that might make it harder for supporters of
Aristotle to approve them. I hope that readers will gradually get used
to my principles, and recognize their truth, before they notice that
they destroy the principles of Aristotle." Unlike his earlier
work, *The World*, the *Meditations* parts ways with the
"old" science without explicitly forwarding controversial
views, like that of the Copernican heliocentric model of the solar
system. Specifically, the Cartesian view denies that physics is
grounded in hot, cold, wet, and dry. It argues that contrary to
Aristotle's view, such "qualities" are not
properties of bodies at all. Rather, the only properties of bodies
with which the physicist can concern him or herself are size, shape,
motion, position, and so on--those modifications that
conceptually (or logically) entail extension in length, breadth, and
depth. In contrast to Aristotle's "qualities," the
properties (or modes) of bodies dealt with in Cartesian physics are
measurable specifically on ratio scales (as opposed to intensive
scales), and hence are subject in all the right ways to mathematics
(Buroker, pp. 596-7). This conception of matter, conjoined with
the sort of mathematics found in the *Geometry*, allies itself
with the work of such Italian natural philosophers as Tartaglia,
Ubaldo, and Galileo, and helps further the movement of early thinkers
in their attempts to establish a mathematical physics.



Descartes' letter to the "learned and distinguished
men" of the Sorbonne, which is appended to the
*Meditations*, suggests that he was trying to pitch the
*Meditations* as a textbook for the university. Though the
endorsement of the Learned Men would not have guaranteed that the
*Meditations* would be accepted or used as a textbook, it could
certainly be viewed as an important step to getting it accepted.
Unlike today's notion of a textbook, in Descartes' day
"textbooks" were intended mostly for teachers, not
students. Typically, at the close of a teacher's career, his
notes would be published for the benefit of those who would go on to
teach such course material. The awkwardness of Descartes's
seeking the acceptance and use of his *Meditations* by teachers
is amplified by the fact that he was not a teacher himself.
Consequently, his seeking "textbook" status would have
very likely been viewed by those Learned Men as being a bit
pretentious. He was, it could be said, a freelancer with no academic
or political ties to the university (outside of his connection to
Mersenne). And, he certainly lacked the credentials and reputation of
someone like a Eustachius, whose widely used textbook of the period is
of the sort the *Meditations* was in all likelihood aimed at
replacing. Although the *Meditations* seems to have been
endorsed by the Sorbonne, it was never adopted as a text for the
university.


## 4. The *Principles*



Soon after his encounter with the Sorbonne, Descartes' public
life was further complicated by the Dutch theologian, Gisbert Voetius
(1588-1676). Voetius had attacked Regius, a Dutch physician who
taught medicine at the University of Utrecht, for his having taught
certain "Cartesian" ideas that conflicted with traditional
theological doctrine. Regius was friend to both Reneri and Descartes,
and was a strong adherent to Descartes's philosophical views.
Voetius tried to have Regius removed from his position as professor,
and attacked not only Descartes' work but his character. In his
defense Descartes entered into the debate. The controversy would leave
Regius confined to teaching medicine, and his published defense of
(his conception of) Cartesian thought would be officially condemned by
Voetius, who in five years time would rise to the position of
University rector. At the end of the debate, which off and on lasted
about five years, the situation ultimately became desperate for
Descartes. He feared being expelled from the country and of seeing his
books burned. He would even seek protection by asking the Prince of
Orange to intervene and quell Voetius' attack.



In 1643, at the age of forty-seven, Descartes moved to Egmond du Hoef.
With the Voetius controversy seemingly behind him (though, as
mentioned above, it would again raise its head and climax five years
down the road), Descartes and Princess Elisabeth of Bohemia began to
correspond. In this exchange, Princess Elisabeth probed Descartes on
the implications of his commitment to mind-body dualism. During this
time, he completed a final draft of a new textbook, which he had begun
three years earlier, the *Principia Philosophiae*
(*Principles of Philosophy*), and in 1644 it was published. He
dedicated it to Princess Elisabeth.



The *Principles* is an important text. The work is divided into
four Parts, with five hundred and four articles. Part One develops
Descartes' metaphysics. Although it would appear to be a quick
run through of the *Meditations*, there are a number of
dissimilarities. For example, the order of presentation of the proofs
for God's existence, which some have argued is significant,
found in the Third and Fifth Meditations, is reversed in the
*Principles*. The principles introduced in Part Two are based
on the metaphysics of Part One. And, the subsequent physics developed
in Parts Three and Four is based upon the principles of Part Two.
Although the physics turns out to be unsound, the *Principles*
nevertheless inspired such great thinkers as Robert Boyle
(1627-1691), Edmond Halley (1656-1742), and Isaac Newton.
As an important side note, it must be stressed that even though
Descartes had throughout his career put a great deal of emphasis on
mathematics, the physics developed in the *Principles* does not
appear to be a mathematical physics. Rather, it is traditionally taken
to be a conceptual project with only a hint of empirical
overtones--a physics rooted entirely in metaphysics. Arguably,
however, Descartes' work on enumeration, order, and measure in
the *Rules* provides the conceptual machinery necessary for
establishing a 'mathematical' physics--a conceptual
machinery that is carried over to the *Principles* (Smith 2003,
2010). Two parts, never completed, were originally intended to deal
with plants, animals, and man. In light of this and what Descartes
says in a 31 January 1642 letter to the mathematician Constantijn
Huygens, it is plausible to think that the *Principles* would
have looked something like *The World* had it been completed as
planned.



One of the more controversial positions the *Principles*
forwarded, at least according to Newton, was that a vacuum was
impossible. Descartes' rejection of the possibility of a vacuum
followed from his commitment to the view that the essence of body was
extension. Given that extension is an attribute, and that nothing
cannot possess any attributes (AT VIIIA 25; CSM I 210), it follows
that "nothingness cannot possess any extension" (AT VIIIA
50; CSM I 231). So, any instance of extension would entail the
presence of some substance (AT VIIIA 25; CSM I 210). In other words,
vacuum, taken as an extended *nothing*, is a flat
contradiction. The corporeal universe is thus a plenum, individual
bodies separated only by their surfaces. Newton argued in his *De
Gravitatione* and *Principia* that the concept of motion
becomes problematic if the universe is taken to be a plenum. Another
controversial position was Descartes' insistence that matter is
infinitely divisible. Gassendi, and later Cordemoy, argued that there
must be a bottom, a 'substance,' to the physical universe
upon which the being of all corporeal things depend. In line with the
ancient atomist Epicurus, they argued that if matter was infinitely
divisible, so dividing it would show that there was no
bottom--and so, corporeality would not be substantial. So, if
corporeality is substantial, as Descartes himself had claimed, there
must be a minimum measure of extension that could not be divided (by
natural means, anyway). And so, there are atoms. But, this conclusion
is something that Descartes explicitly rejects in the
*Principles*.


## 5. The *Passions*



In 1646, as a result of the probings of Princess Elisabeth, Descartes
completed a working draft of *Passions de l'ame*
(*Passions of the Soul*). During this year another prominent
political figure began to correspond with Descartes, Queen Christina
of Sweden. And, Regius published what he took to be a new and improved
version of Cartesian science, which as we now know would draw the
wrath of Voetius. But Regius did not stop there, for he seemed to have
found important differences between his "Cartesian" view
and that of Descartes', and attempted to separate the two,
publishing a broadsheet that listed twenty-one anti-Cartesian theses
(which his version of "Cartesian" science rejected). In
response to this, Descartes wrote a single-page printed defense that
was posted on public kiosks for all to read. Published in 1648, the
*Notae in Programma Quoddam* (*Notes on a Program*-also
referred to as *Comments on a Certain Broadsheet*) is
Descartes' public defense. However, as mentioned earlier,
tensions mounted as a result of the public exchange and Descartes felt
his way of life in the Netherlands to be threatened. As luck would
have it, an admirer and friend of Descartes'--Chanut, who
worked for Queen Christina's court--and Queen Christina
herself began probing Descartes about the possibility of coming to
Sweden. And, after a not too lengthy correspondence, Queen Christina
offered Descartes a position in her court. For many reasons, which
would certanily include those related to his concerns about Voetius,
Descartes accepted the offer. And, in 1649 he left for Sweden. 



Queen Christina at first required very little from Descartes. However,
according to Gaukroger, this would change. For, after he had some time
to settle in, she ordered him to do two things: first, to put all of
his papers in order, and secondly, to put together designs for an
academy (Gaukroger, p. 415). Arguably, Descartes had some idea of how
the latter might be done by way of his experience in Breda. In January
of 1650 Queen Christina began to require Descartes to give her lessons
in philosophy. These apparently would begin at five in the morning and
would last for about five hours. They were given three days a week
(Gaukroger, p. 415). During this time Descartes published the
*Passions*, the work having emerged primarily from his
correspondence with Princess Elisabeth (to whom he had dedicated the
*Principles*). One aim of the *Passions* was to explain
how the emotional (and thus moral) life of a human being was connected
to the soul's being essentially united to a body. Simply put, a
'passion of the soul' is a mental state (or thought) that
arises as a direct result of brain activity. Such passions can move us
to action. Since this is so, Descartes suggests that one needs to
learn to control one's passions, for they can move one to
perform vicious acts. Critics of Descartes, including Elisabeth,
argued that Descartes' metaphysical commitments put real
pressure on the view expounded in the *Passions*. For,
according to Descartes' metaphysics, the nature of mind is to
think and the nature of body is to be extended in length, breadth, and
depth. One view concerning causation, a view that Descartes's
critics seemed to have attributed to him, is that one thing causes
another to move, for example, by way of contact. Contact, in this
context, seems to be possible only by way of surfaces. Now, bodies,
since they are extended and thus have surfaces, can come into contact
with one another and thus can cause one another to move. However, if
minds are not extended, they lack surfaces. And, if they lack
surfaces, there is no way in principle for bodies to come into contact
with them. Thus, there is no way in principle for bodies to move
minds, and vice versa. That is, minds and bodies cannot in principle
causally interact. And so, if the view expounded in the
*Passions* requires that bodies and minds be capable of causal
interaction, and Descartes' metaphysical commitments make such
interaction impossible, Descartes' metaphysics puts a great deal
of pressure on the view expounded in the *Passions*.



Although things seemed to be moving forward, they were not going as
well as one would have hoped. In a letter to Bregy, for instance,
dated 15 January 1650, Descartes expresses reservations about his
decision to come to Sweden. He sees himself to be "out of his
element," the winter so harsh that "men's thoughts
are frozen here, like the water" (AT V 467; CSMK III 383). Given
the sentiment expressed in the letter, this remark was probably
intended to be as much Descartes's take on the intellectual
climate as it was about the weather. In early February, less than a
month after writing Bregy, Descartes fell ill. His illness quickly
turned into a serious respiratory infection. And, although at the end
of a week he appeared to have made some movement towards recovery,
things took a turn for the worse and he died in the early morning of
11 February 1650. He was fifty-three years old.