Discourse on Method for Reasoning Well and for Seeking Truth in the Sciences Rene Descartes (1637) Malaspina Great Books.

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Transcript Discourse on Method for Reasoning Well and for Seeking Truth in the Sciences Rene Descartes (1637) Malaspina Great Books.

Discourse on Method for
Reasoning Well and for Seeking
Truth in the Sciences
Rene Descartes
Malaspina Great Books
Original Discourse
• Optics
• Meteorology
• Analytical Geometry – this work is familiar to
students of modern science. It ranks with Isaac
Newton’s Principia as the most important
contributions to mathematical reasoning from
the 17th century and the most important
contribution to geometrical reasonong since
Descartes’ Epistemology
• Descartes’ Method represents a new
attitude towards reasoning – an approach
that if applied judiciously towards the right
subjects does bare fruit.
Fundamental Questions
What is unique about the Method?
Does it work?
How does it work?
What evidence is there that the Method
does work?
• What opportunities and what application
areas did Descartes’ Epistemology open
Compare the Method to conventional
Examine the rules in detail
Offer examples of Descartes’ reasoning as
applied to historical and contemporary
problem solving
Alternate Modalities
• Descartes Method represents an early and “classical”
attempt to model how systematic knowledge occurs.
• Descartes’ conjecture is that this process is formulaic or
subject to a computational strategy
• Non-classical modern theorists have argued recently that
there can be no such method – as such – because
cognition or consciousness itself involves the action of
intellectual processes that are impossible to formalize –
because (simplistically) they are non-classical – meaning
subject to quantum phenomena – phenomena that were
unknown in Descartes’ era.
• In simple terms such processes do not adhere to the
normal rules of traditional logic.
Historical Approach to “Knowing”
• Scientific – Greek Platonism
• Non-Scientific – Judeo-Christian
The Greek View
• Knowledge is a kind of “recollection” of
universal ideas (or forms). These ideas
are accessed through a process of
reasoning called dialectic.
The Hebraic View
• Knowledge is revealed. Knowledge
resides in authority and acquired through
Faith (capital F)
The Competition
• Francis Bacon (1620) – admired greatly by
Descartes - provided a systematic
inductive mode of scientific reasoning in
Novum Organum.
• This Method was very successful (and
fundamental to modern empirical
approaches) but relies on sense
Cartesian View
• Greek & Judeo-Christian based epistemologies
are set aside
• Distrust sense – Greek view relies on this
• Put God aside – no a priori God
• The Cartesian Approach is rooted in skepticism.
There are no forms; there is no authority; faith is
• Unlike Bacon’s inductive approach, the
Cartesian Method is fundamentally deductive
Background on Cartesian Method
• Descartes’ Method profoundly influenced by Galileo’s
success and by Galileo’s censure
• Descartes intended to publish a substantive defense of
the heliocentric model in 1633 in Le Monde
• Galileo was condemned by the church in the same year
• Descartes (like Galileo) did not believe that Galileo’s
heliocentric views were prejudicial to religion but he
worried that his own work might also be censured
• Descartes withdrew his manuscript on heliocentric
• The Discourse on Method was published in 1637 – 5
years later
Radical Nature of the Cartesian
• Descartes asserts that the world is knowable –
God intends we know it – but the Method used
must be proper
• Objective of Method: eliminate influences of
opinion or systemic bias – (modern idea)
• Refuse to accept the authority of Aristotelian
and Scholastic philosophies
• Refuses to accept the “obvious” authority of his
own “obvious” senses
• Accept only that which is “clear and distinct”
The Matrix
• Dream or Reality
First Rule
• The first rule was that I would not accept
anything as true which I did not clearly
know to be true. That is to say, I would
carefully avoid being over hasty or
prejudiced, and I would understand
nothing by my judgments beyond what
presented itself so clearly and distinctly to
my mind that I had no occasion to doubt it.
Second Rule
• The second was to divide each difficulty
which I examined into as many parts as
possible and as might be necessary to
resolve it better.
Third Rule
• The third was to conduct my thoughts in
an orderly way, beginning with the
simplest objects, the ones easiest to know,
so that little by little I could gradually climb
right up to the knowledge of the most
complex, by assuming the same order,
even among those things which do not
naturally come one after the other.
Fourth Rule
• And the last was to make my calculations
throughout so complete and my
examinations so general that I would be
confident of not omitting anything.
Intellectual Operations in the
• Intuition – apprehension of simple natures
• Deduction – inference of necessary
connections between simple natures
• Enumeration – process of review designed
to avoid intellectual “copying” errors
• A system designed to be simple, clear,
orderly and self-checking
• Clarity – all aspects of an idea when reduced to
simplest form are seen
• Distinctness – the limit or boundary of simple
idea is discerned; and therefore all relationships
between two or more simple ideas are clearly
seen as relationships between ideas and not
part of the simple idea itself.
• Innate Ideas – Only innate ideas (God, first
principles, etc.) can be certain; adventitious
(sensation) and fictitious ideas never certain
The Foundation of the Method
• Descartes’ Method rests on a foundation
built from three incontrovertible (not
susceptible to doubt) and interconnected
elements: 1) The doubter is; 2) Reason is;
3) God is.
• These elements are interconnected in that
3) acts as guarantor for 1) & 2)
• This explains why Descartes offers three
separate “proofs” for 3)
Proofs of the Existence of God
• It is impossible to have an idea of perfection
unless that idea placed by a perfect nature (p.
• Proof from geometry. Existence of god more
certain than existence of geometric object (p.
• It is unreasonable to deny insufficiency of
evidence for God’s existence. There is thus
sufficient evidence for the existence of God (p.
The World Exists - Dualism
• Extension (space-time) and extended
substance (res extensa) represent a clear
and distinct idea. The world is mechanistic
and its motions (placed by god) determine
• Dualism: thinking substance (res cogitans)
– God and soul – is distinct from the world
A Hypothetical Example of
Cartesian Method
• A question on the nature of the world susceptible to
Cartesian method: What is the world? Is it finite? Is it
• Whatever conjecture reason currently offers will be
subject to doubt (first rule)
• Divide this question into as many parts as necessary to
resolve it better (second rule).
• Seek an orderly architecture to unify the distinct
elements (third rule)
• Develop a mathematical description that prescribes this
unity and serves as a check for the reasoning (fourth
A Solution
• The world is comprised of space, time and matter
(clarity). Seek distinctness with respect to these three
clearly reduced elements.
• Infinite matter, time and space generate indistinct
• Bring distinctness to space and time by redefining these
as bounded yet counter-intuitive elements (i.e. elements
not based on senses)
• Modern relativistic physics achieves this end by defining
space and time as finite and bounded and then devising
a non-intuitive non-euclidian mathematical formalism to
bring order to those redefined elements
Problems Unsolved by Descartes
• Relationship between infinite substance (God)
and finite substance (the world)
• Relationship between the thinking soul (or mind)
and the body
• Subsequent attempts to offer solutions: 1) unify
Plato & Descartes (Spinoza); 2) Unify Augustine
& Descartes (Malebranche); Unify Aristotle &
Descartes (Leibniz).
• Cartesian coordinate system (divide
problem into simplest parts – first rule)
• Histogram
• Analytic Geometry
• Foundation for infinitesimal calculus (climb
up to knowledge of the most complex –
third rule)
• Never accept as true unless clear –
skepticism at base of modern science.