René Descartes’ Views

The following is taken directly from an outline provided by Karen Warren. It provides an excellent overview of Descartes’ views and methods. The most important points are at the end, when explaining his foundations of human knowledge. It is from here that the mind/body dualism arises, and that which Princess Elizabeth questions in her correspondence to him.

I. Introductory Comments (Jump to Descartes’ Method)

A. Classical and Medieval Views about the Nature and Method of Philosophy

B. Descartes as “the father of modern philosophy”

1. He started the new theory of knowledge which has been the heart and soul of modern Western philosophy.

2. His concept of the method of philosophical inquiry had 2 important characteristics:

a) It is a method of inquiry (vs. a method of proof): a way of finding out things and making sure one makes no mistakes; the point of view of the ignorant learner

b) It is a method of doubt: a refusal to accept anything as true unless it is absolutely certain.

3. As a consequence of Descartes’ method, a transformation in the central nature of philosophy was begun. This is what R.P. Wolff (About Philosophy) calls “the epistemological turn” (pp. 230, 232), a reversal in the order of precedence of two basic questions:

a) What exists? (About the nature of the universe, of being): Metaphysics

b) What can I know to exist? (About the nature of knowledge, the mind, reasoning): Epistemology

Before Descartes: Metaphysics took precedence over Epistemology.

After Descartes: Epistemology took precedence over Metaphysics.

C. Descartes’ Quest for Certainty

1. He was disappointed with and rejoiced the authority of “learned men”:

a) He claimed to realize that there was no clear and certain knowledge (Discourse, p.7).

b) He distrusted the conventional wisdom of custom and tradition (Discourse, p. 11).

2. His distinctive approach: disregard the traditional start form scratch; secure philosophy (and all science) on firm, solid foundations by seeking and arriving at certain, indubitable truths.

3. He offered as a standard of proof absolute certainty.

4. His resolve: to strop himself of all opinions and beliefs (formerly) held to be true (Discourse, p.14; Meditations, in Cahn, p. 310)

D. Descartes’ Confidence in Power of Reason to Achieve Truth, if Used Properly

1. Humans are by nature rational beings (Discourse, pp. 5, 6).

2. Mathematics provides the best example of the proper use of our rational capacity: because of the certainty of its demonstrations and the evidence of its reasonings” (Discourse, p. 9).

a) The standard of any instance of genuine knowledge is provided by geometrical-like demonstrations: the establishment of axioms or first principles and the derivation of consequence from them.

b) The method by which all genuine knowledge is achieved is exemplified by the method of geometry.

3. Descartes’ Method as the “the mathematical method”

a) To isolate first principles through a method of systematic doubt;

b) To build philosophy on firm foundations (see Discourse, p. 9, 12, 18, 22);

c) To do more than “mere reform” (see Discourse, p. 22);

d) To distinguish his method from the method of the skeptics who deny that genuine knowledge can be achieved (see Discourse, p. 22).

II. Descartes’ Method (back to top) (Jump to The Rational Foundations of Human Knowledge)

A. Intuition and Deduction: the two operations by which reason achieves certain knowledge (from Rules for the Direction of the Mind, ca. 1630)

1. Intuition: “the conception which an unclouded and attentive mind gives us so readily and distinctly that we are wholly freed from doubt about that which we understand”

a) Knowledge of first principles or primary truth (e.g. Descartes’ Knowledge that he exists) is intuitive; to apprehend clearly and distinctly that he exists is to intuit his existence.

b) Intuition is the basis of all certain knowledge.

2. Deduction: inference from facts that are known with certainty.

a) Those judgments or beliefs which are not self-evidently true must be established as true by deduction.

b) Deduction is based on intuition; each deductive step is based on intuition.

3. Point: Every philosophical claim must either be intuitively obvious (i.e. impossible to doubt) or be deducible from other claims which are intuitively obvious, in the same way that conclusion of mathematical proofs are deductible from the premises.

B. Descartes’ Process: doubt everything almost to the point of total skepticism; then, having discovered through rational intuition some belief or claim which is absolutely certain and indubitable, proceed in a step-by-step fashion of deductive reasoning to demonstrate the true nature of “man” and the universe.

C. Descartes’ 4 Rules: the “true method of arriving at a knowledge of all things of which my mind was capable” (Discourse, p. 16):

1. Rule 1: Method of Systematic Doubt: “…accept nothing as true which I did not clearly recognize to be so: “...to accept…nothing more than what was presented to my mind so clearly and distinctly that I could have no occasion to doubt it.”

2. Rule 2: Analysis: “…divide up each of the difficulties that I examined into as many parts as possible.”

3. Rule 3: Synthesis or Deduction via the test of Rational Intuition: “carry on my reflection in due order, commencing with the objects that were most simple and easy to understand…to knowledge of the most complex…”

4. Rule 4: Avoidance of Deductive Error: “…in all cases to make enumerations so complete and reviews so general that I should be certain of having omitted nothing.”

D. Underlying Assumptions of Descartes’ Method

1. Nature itself has a geometrical-mathematical order or form (the assumption of the new physics)—a metaphysical view

2. All knowledge can be ordered or organized geometrically (i.e. that all our true judgments or beliefs are rationally connected like the parts of a geometrical demonstration).

3. Only when our understanding takes on a geometrical-mathematical order or form can it represent correctly the real nature of things—an epistemological view.

4. Philosophy is itself the “universal science,” and not merely a method of “true science” which involves knowledge of the first principles of human understanding and the system oft truths deducible from these basic truths.

E. Descartes’ Program of Methodological Doubt

1. Aim: to arrive at judgments the truth of which is beyond doubt (“certain and indubitable”) by applying his first and basic rule (Rule 1) (see Meditations, in Cahn, pp. 310, 313).

2. What Descartes doubts:

a) Information arrived at through the senses;

b) Information gained through memory;

c) All reasoning or conclusions arrived at through reasoning.

3. Limitations on Descartes’ program of methodological doubt: Certain beliefs are put outside the scope of the method (Discourse, p. 18-19):

a) The revealed truths accepted by religious believers;

b) Some basic ethical maxims about what is “probably the best” way of conducting his life;

Descartes: Having exempted these religious and ethical beliefs, “I judged that as far as the rest of my opinions were concerned, I could safely undertake to rid myself of them” (Discourse, p. 22)

4. Concern with certainty in an epistemological sense is different from certainty in a psychological sense: He is not trying to discover some belief which he feels subjectively so confident about that he can’t bring himself to doubt its truth. Rather, he is seeking to discover basic beliefs about which he could not possible (or, conceivably) be mistaken in thinking them true.

F. 2 Hypotheses (Used in Conjunction with the Method of Systematic Doubt)

1. The Dream Hypothesis (Meditations I, in Cahn, p. 312): It is impossible to distinguish waking life from dreams.

2. The Evil Genius Hypothesis (Meditations I, in Cahn, p. 312-3): There is an all-powerful, deceitful evil demon who has employed all his energies in deceiving Descartes.

Note: Descartes’ concern with epistemological certainty explains why he resorts to entertaining these two hypotheses; they show the possibility of our being mistaken in what we usually accept as true.

G. Solipsism: Only one’s mind and one’s impressions exist.

III. The Rational Foundations of Human Knowledge (back to top)

A. The Cogito: 2 Formulations

1. “I am, I exist is necessarily true every time that I pronounce it or conceive it in my mind” (Meditations II, in Cahn, p. 313).

2. “I think; therefore I am” (Discourse)

B. The Cogito as the Fundamental Principle of Human Knowledge

1. Reasoning: Descartes concludes that although I can be deceived about the existence of everything I think about (including the physical world and my own body), I cannot be deceived or mistaken in thinking that I exist (as a thinker who is deceived), since my thinking is the necessary condition of my being deceived.

a) In the very act of denying my existence I must affirm or presuppose it.

b) Doubt becomes self-canceling; human thought in grounded in an indubitable (necessary, certain) truth.

2. The existence of the ego (the “I” or conscious subject) is not established by logical inference buy by rational intuition. It is directly seen to be true by his powers of rational inspection and reflection; it is recognized as certain by the “natural light of reason.”

3. The nature of this “I” in “I am” is a thinking, non-spatial, immaterial thing, res cogitans; by contrast, the body is a non-thinking, extended, spatial, material thing, res extensa.