Lecture 17 Notes

Introduction to Descartes

Plan of the Lecture

I.    Background to the Second Half of the Term
II.   Important Characteristics of the Modern Period
III.   Introduction to Descartes
IV. Meditation 1
V. Meditation 2: The Cogito

I. Background to the Second Half of the Term

With the move from Plato and Aristotle to Aquinas, we moved from the classical or ancient period to the Medieval.
With the move from Thomas Aquinas to Descartes, Hobbes, and Kant (later, to Dostoevski) we move from the Medieval to the modern period of European history and thought.

II. Important Characteristics of Modern Period

A. Age of Discovery

The age of discovery begins with the explorations of the Portuguese. It culminates in Columbus’s voyage of 1492 and Magellan’s circumnavigation of globe.
It is made possible by national states funding expeditions. Returns from these expeditions brought enormous amounts of money into them.

B. Age of Humanism

Scholars return to classical Greek and Roman learning and literature during 1500’s.
It marks the beginning of modern biblical criticism.
There is increased emphasis on humanistic, secular values.

C. Age of Science

In 1543, Copernicus published hypothesis of heliocentrism.
In 1610, Galileo published an argument, based on evidence gathered by telescope, that Copernicus was right.
In the mid-1600’s, Newton published the work in which he invented mathematical physics. His work effectively brought to an end the hegemony of Aristotelian science.

D. Age of Reformation

In 1517, a young German monk named Martin Luther tacked "95 Theses" to church door in Wittenberg, Germany thereby changed face of Europe forever. Luther may only have wanted to reform Catholic Church, but he instead invented Protestantism. It spread rapidly throughout Germany, Switzerland, finally reaching England.
By the 1530’s, states could sever financial, political, and legal ties with Rome.
The end of Roman Catholic hegemony brought large-scale religious and moral pluralism to Europe. Some continued to think of Christendom as spiritual unity, but Protestantism and pluralism were entrenched in European life by last third of 1500’s.

E. Comparative Characteristics of the Late Medieval Period and the Modern Period

Late Medieval Period	Early Modern Period
Increasing concentration of power in nation-states	Nation-states are the political entities of Europe
Large-scale religious unity of Catholic Christendom	Large-scale religious pluralism prevails in Europe
Dominance of religious authority of Catholic Church	Many nation-states and citizens independent of Church authority
Intellectual ferment over recovery of Aristotle	Intellectual ferment over rise of science and humanistic studies
For Thomas Aquinas, paradigm of knowledge is philosophy and theology	Paradigm of knowledge is increasingly science, and the mathematics on which it is based

F. Changes in Philosophy

By 300 years after Aquinas’s birth, his intellectual, political and spiritual world was in fragments. By 350 years after his death, it was ground to dust, blown away.
Philosophy concerns itself with the place of human beings in world with what they are, what they are to do, how they are to live.
Therefore, philosophy must change with the world: old accounts of politics are swept away and new ones defended. Old accounts of ethics are put aside and new ones are articulated. Old accounts of how human beings can know should be forgotten and new ones put forward. Philosophy must begin anew: enter Descartes.

III. Introduction to Descartes

A. Life and Times

Rene Descartes 1596-1650.
He was a contemporary of Shakespeare (d. 1620), Galileo (d. 1643), and Rembrandt (d. 1669).
Philosophy aside, his life was made interesting only by circumstances of death, tutoring the Swedish queen.

B. Descartes' Philosophical Program

He studied Thomistic philosophy as taught in his time, knew it well, and accepted it for a time.
He also studies of physics and mathematics, giving his name to Cartesian geometry, which he invented. This set of studies convinced him of its inadequacy of Thomistic philosophy, insofar as he was impressed with the certainty and structure of geometry.
He wanted all knowledge to be as certain as that found in geometry, and wanted a philosophy to show how this could be so.

IV. Meditation 1

A. The Existence of Doubt

We have vast number of beliefs.
But not many of them seem to enjoy certainty. With sufficient ingenuity, we can see that all can be doubted:

Sense and memory deceive us.
We dream when we are sleeping
Could it be that God deceives us?
It is certainly possible that an evil genius, a demon, is deceiving us so that nothing we believe is true.

B. The Method of Doubt

A hypothesis is necessary to determine which beliefs are certain. Through this hypothesis, we can:

determine which beliefs a person committed only to certainty should believe.
isolate a few beliefs which are as certain as the axioms of geometry seem, and from there, get to others.

"Archimedes, that he might transport the entire globe from the place it occupied to another, demanded only a point that was firm and immovable; so, also, I shall be entitled to entertain the highest expectations, if I am fortunate enough to discover only one thing that is certain and indubitable." (Meditation 2, Paragraph 1)

Descartes hopes to show that much of what we think we know is in fact secure, if he can find but one secure foundation. But what can it be?

V. Meditation 2: The Cogito

A. This is the most famous passage in all of philosophy:

"But I had the persuasion that there was absolutely nothing in the world, that there was no sky and no earth, neither minds nor bodies; was I not, therefore, at the same time, persuaded that I did not exist? Far from it; I assuredly existed, since I was persuaded. But there is I know not what being, who is possessed at once of the highest power and the deepest cunning, who is constantly employing all his ingenuity in deceiving me. Doubtless, then, I exist, since I am deceived; and, let him deceive me as he may, he can never bring it about that I am nothing, so long as I shall be conscious that I am something. So that it must, in fine, be maintained, all things being maturely and carefully considered, that this proposition (pronunciatum ) I am, I exist, is necessarily true each time it is expressed by me, or conceived in my mind." (Meditation 2, Paragraph 3)

B. How is the Argument to be Understood?

I have persuaded myself that everything is subject to doubt.
But I was persuaded and I did the persuading.
THEREFORE "I did exist".

C. Objection and Reply

Objection: Isn’t it possible I am deceived about my existence?
Reply: "If he is deceiving me, there is no doubt that I exist."

D. The Inference

Engagement in mental activity, cogitation, proves to me that I exist while doing it.
Cogito ergo sum means "I think" therefore "I am".
'Think' covers a range of mental activity, including: doubt, affirm, deny, and know.
The secure foundation of all knowledge--his and ours--is this inference.

E. Two Points the Argument Does Not Prove

We conceive of ourselves as persisting through periods of mental inactivity, including coma, dreamless sleep, and unconsciousness. The argument is consistent with our "popping" in and out of existence as mental activity begins and ceases. Therefore, the argument does not show that we exist in way we may usually think.
We normally conceive of ourselves as sensing things outside us, as imagining based on sensation, as beings with bodies. But the fact that we are persuaded and deceived is consistent with our lacking bodies, lacking sensation, and lacking imagination. Therefore, the argument does not prove that we exist as we normally conceive ourselves to be.

F. Two Questions About the Argument that Descartes Doesn’t Consider:

In (E) above, we saw that Descartes thinks the argument establishes only that I exist whenever I am engaged in mental activity. This is consistent with my popping in and out of existence. But does the argument even prove that much? It seems only to license the claim that some thinking being exists during episodes of mental activity. Why think any of these beings are identical with any other?
Why conclude that thinking implies an 'I" at all? Descartes moves from "I think" to existence of thinking thing, a thinking subject. But is he entitled to the premise "I think", or rather to the weaker "there is thinking going on", that doesn’t obviously imply a subject. Perhaps he supposes thinking and self-awareness go together.

Citation: Weithman, P. (2006, September 19). Lecture 17 Notes. Retrieved November 23, 2009, from Notre Dame OpenCourseWare Web site: http://ocw.nd.edu/philosophy/introduction-to-philosophy/lectures/lecture-17-notes.