Descartes Discourse on Method 1637

"The Enlightenment" is also often called "The Age Of Reason", so if you want to understand what the Enlightenment is all about, you do well to understand what "reason" is.  The easiest way to do this is to understand Descartes, the father of modern reason.

We're also interested in Descartes' Cogito for a number of reasons that help explain how people were radically rethinking everything at this time, and I do mean everything, including, especially, how to think.  His thinking represents the response to the manner in which "science" (such as the findings of Galileo and others, in the previous century) had challenged what everyone had for a thousand or more years assumed to be true: the philosophical assumptions of theology, and, because religious belief was essentially the only form of belief at the time, the philosophical assumptions of all philosophy.

What is truth, and how do we know when we've found it?

Like most philosophers, Descartes was interested in how we could differentiate between true and false ideas.  It's the most basic of all philosophical questions: how do we know when something is correct, or right, or "true"?  This seems simple enough until you realize that for thousands of years nearly all great thinkers -- and all the not-so-great thinkers -- had gotten the basics of astronomy wrong and that things that appear "true" were now proven to be utterly false: such as the sun certainly appears to revolve around the earth, and the earth certainly appears to be the center of the universe, or even that the stars hung from a firmament, a canopy, not far above our heads.

Remember as well that for thousands of years the seemingly smartest people hadn't known about that thing called "America" or, say, Australia, the North and South Poles, or what the stars actually were....

Like Socrates, Descartes concludes that the best place to start understanding what is true is with doubting everything that you know: that is, with radical skepticism.

Radical Skepticism and Cogito Ergo Sum = I Think, Therefore I Am.

This element of Descartes' philosophy is probably our main concern in this class: his willingness to doubt everything -- even his own existence and the existence of God -- and in so doing change the course of human thinking (or perhaps "reinvent" as his method brings us back to Socrates' and the Classical Greek approach to knowledge).  In a nutshell, Descartes cogito means:

a) Do not assume anything is true until it has been proven (which, of course, raises the question: what constitutes "good proof"?)

b) Reject as “truth” that founded only Authority (don't believe everything you are told, even if it was believed by someone really super smart, like Aristotle etc.; people have prejudices and make errors, even in math, where we can prove that the errors are human and not objective)

c) Reject as “true" all ideas but those that are "distinct" and "clear", by which he more or less means "beyond doubt" (again, this sort of returns us to the question we started with: what is "beyond doubt"?).

Descartes is fundamentally a mathematician, and in many ways all he does is return Western thinking to the Greek tradition of equating "proof" with the certainties only, at the time, found in mathematical thinking.  Everyone agrees that 2+2=4, not because the Bible told you so, not because Aristotle thought so, but because it can be proven, both through observation and mathematical testing.  This is in many ways Platonic Idealism without Plato's mystical otherworld "Form of the Good".

Radical Skepticism and Cogito Ergo Sum
If the true skeptic doubts everything, he must doubt the reality of his own existence -- that's the radical part: what's the most radical, extreme thing you can doubt? That you yourself exist.  And then, at the time, secondly, that there is a god -- and so Descartes does exactly that: he starts with doubting the most radical  and fundamental  of all assumptions: that he himself exists.  He then attempts to come up with rational, irrefutable "proof" of his own existence.  He famously deduces that if there is someone asking the question "Do I exist?" there must be someone doing the asking;  all other explanations are rationally false (someone cannot ask if he exists unless there is someone to do the asking).  In other words, someone is thinking about whether or not he exists, and this proves he exists.  Yeah, I agree: this sounds more like Dude, Where's My Car? than it does philosophy, but whatever.  So, his proof of his own existence: Cogito Ergo Sum: "I think, therefore I am."

So, again, the reason Cogito Ergo Sum is easily one of the most important phrases in human history is that it is shorthand, a symbol of, Descartes', and thus modern philosophy's, radical skepticism.  It is the foundation not only of philosophy but of the philosophy that grows out of Descartes' method: science.  

To understand how "radical" this is, contrast it with the concept of "faith", which is the basic foundation of all religious belief, best summarized in Hebrews 11:1: "Now faith is the substance of things hoped for, the evidence of things not seen." (King James version) 

Descartes on God
Descartes' arguments concerning the existence of God interest us for a couple reasons.  First, they suggest that no matter how "radical" the philosopher or his skepticism and doubt, there were no atheist philosophers in this day and age;  doubt had not, it really appears, reached that degree of radicalism; one might "doubt" that there is a god, but ultimately one worked back to belief.

More importantly, though, Descartes' argument for the existence of God show how difficult it is to truly wrestle with his own categories of what is or isn't "distinct" or "clear" in terms of figuring what constitutes "proof" of what is true.  One can prove one's own existence, as he does above, but it is an entirely different thing to prove the veracity of those things outside ourselves.

His argument condensed:

He imagined that an "Evil Deceiver" (such as Satan or, to make this more current, perhaps some sci fi evil scientist) might have created a universe that was entirely fictional and was thereby able to fool us into thinking that our existences were "real".  This is the metaphor best presented in The Matrix:  with enough evil or magic or, in The Matrix, scientific technology, an Evil Deceiver could totally trick us all into mistaking fantasy and fiction for "reality" or Truth.

So, how to figure out whether or not this is the case or not: are our lives real or simply fictions in the Matrix?

Sadly, for atheists, Descartes suggests we can't answer this question without a belief that there is something more powerful than the Evil Deceiver;  he calls this thing "God".  It's worth thinking for a minute that he's actually right:  you cannot break the Matrix code unless there is someone smarter than the Matrix -- thus Neo and those other dudes wearing lots of black leather have to exist in order for humanity to be freed from the matrix, from false belief.  (We return to this film and its philosophical metaphors at the semester's end).

Descartes deduced that the "truest" ideas were "innate" (a belief soon challenged by John Locke):  our perceptions of nature could be fooled (the sun really does seem to move) and so we needed to locate "truth" outside mere perception, either in the irrefutable "proofs" of math (see below) or in an idea or "thing" that does not exist in nature but is still innate to our minds (this is Plato's thinking, btw).  What is that idea?  Perfection.  We can imagine the existence of perfection, but it doesn't exist anywhere in nature, in the "real world".  This concept of perfection is, for Descartes and other Christians and theists, that thing called "God". 

Thus, if we could imagine this perfect God but not find it, it must exist. "I bethought myself to find out from whence I had learned to think of something more perfect than I; and I knew for certain that it must be from some nature which in reality was more perfect....  I could not derive it from myself; so that it remained that it had been put in me by a nature truly more perfect than I...God" (408).

Within his own lifetime, however, many pointed out the logical error in this deduction: Descartes violates his own "radical skepticism": the concept of "perfection" or "more perfect" is a concept (an idea), and not necessarily a thing that can be observed. We can directly observe people forming false concepts (the world is flat; women are inferior to men; Keystone light is beer etc.), so the idea/concept "perfection" does not prove the existence of perfection itself, only the existence of the idea of perfection.  So, Descartes' own method proves the existence of the concept, not the "thing itself", "God".

Thus, despite his efforts to “prove” the existence of God through logical deduction, Descartes'  belief in God returns to where it has always been: with faith: “Now faith is confidence in what we hope for and assurance about what we do not see. This is what the ancients were commended for.  By faith we understand that the universe was formed at God’s command, so that what is seen was not made out of what was visible” (Hebrews 11).

Descartes And Math:
At heart Descartes was an important mathematician and, more importantly, he essentially created the philosophical framework that made math the backbone of natural science.  The section of his Discourse that we read also touches on this.

 “The long chains … [math’s ability to simplify and correctly work thru exceptionally difficult problems] … had given me reason to believe that all things which can fall under the knowledge of man succeed each other in the same way [all things can be understood thru mathematical reasoning/principles], and provided that…[the method is correct…we can understand all things this way]”

“…to apply them [agreed upon mathematical principles] to every other subject to which they should prove suitable...everything was so complex I should express them with numbers (simplicity)...I should borrow all the best in geometrical analysis, and in algebra…”

In other words, we should apply mathematical principles to understanding everything. 

Much of the foundation of scientific study and facts comes down to Descartes' idea:  the periodic table of elements is really just the numerical value and weight of the elements of our universe; your genetic code is the numerical breakdown of your structure; the study of physics is the study of how measurable properties interact etc etc -- basically "science" means "those natural things we can prove with numbers," or, more accurately, science is based on "facts" and the definition of a fact is that which can and has been verifiably quantified.

More Stuff:

Descartes broke his “method” down into four parts: (Kemerling)

1.  Systematic Doubt:  Question everything and all previous authorities.  Accept as true only what is absolutely certain.  This is perhaps his most radical and basic step: the foundation of all scientific thinking. (For the sake of English 258, this is what we're most interested in.)

2.  Analysis:  Divide every question into manageable parts and name the parts. Assign symbols (numbers) to elements, so that they can be better understood and managed (think of using calculus to understand economies, the movement of planets, light...etc etc).  Consider how impossible it would have been to complete the human genome project or invent modern medicines without this approach: there would never have been a periodic table of elements to begin with.

3.   Synthesis or Deduction via the test of Rational Intuition:  Begin with the simplest issues and ascend to the more complex.  Start with things you can prove and work from there; make no large assumptions upon which to base a theory.

4.   Avoidance of Deductive Error:  Review frequently enough to retain the whole argument at once.  Re-test, re-test, re-test to ensure that you don't have to much confidence to your theory; continually look for empirical means to test it.

In addition to this method, Descartes came up with some underlying assumptions as well: (Warren) 

1. Nature itself has a geometrical-mathematical order or form (the assumption of the new field of physics)— this is a metaphysical view about the nature of existence itself, and this idea is central to Pope's Essay On Man and most other Enlightenment work (this is the basic ontological view of science).

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).  This is an epistemic view: a philosophy concerning what true knowledge is and how it can be found.

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

These assumptions profoundly effect Enlightenment philosophers: by understanding the inherently logical/mathematically perfect order of the universe we can understand man's place in that universe and we can govern ourselves -- and each other? -- accordingly.