I THINK THEREFORE i am.
RENE DESCARTES.
An evil demon may be making me believe things that are false.
There is nothing of which I can be certain.
But when I say “I am; I exist”, I cannot be wrong about this.
An evil demon could try to make me believe this only if I really do exist.
I am thinking, therefore I exist.
René Descartes lived in the early 17th century, during a period sometimes called the Scientific Revolution, an era of rapid advances in the sciences.
The British scientist and philosopher Francis Bacon had established a new method for conducting scientific experiments, 
based on detailed observations and deductive reasoning, and his methodologies had provided a new framework for investigating the world.
Descartes shared his excitement and optimism, but for different reasons.
Bacon considered the practical applications of scientific discoveries to be their whole purpose and point, 
whereas Descartes was more fascinated by the project of extending knowledge and understanding of the world.
During the Renaissance—the preceding historical era—people had become more skeptical about science and the possibility of genuine knowledge in 
general, and this view continued to exert an influence in Descartes' time.
So a major motivation of his “project of pure enquiry”, as his work has become known, was the desire to rid the sciences of the annoyance of 
skepticism once and for all.
In the Meditations on First Philosophy, Descartes' most accomplished and rigorous work on metaphysics (the study of being and reality) and 
epistemology (the study of the nature and limits of knowledge), he seeks to demonstrate the possibility of knowledge even from the most skeptical of 
positions, and from this, to establish a firm foundation for the sciences.
The Meditations is written in the first-person form—"I think..—because he is not presenting arguments in order to prove or disprove certain 
statements, but instead wishes to lead the reader along the path that he himself has taken.
In this way the reader is forced to adopt the standpoint of the meditator, thinking things through and discovering the truth just as Descartes had 
done.
This approach is reminiscent of the Socratic method, in which the philosopher gradually draws out a person’s understanding rather than presenting it 
already packaged and ready to take away.
The illusory world.
In order to establish that his beliefs have stability and endurance, which Descartes takes to be two important marks of knowledge, 
he uses what is known as “the method of doubt."
This starts with the meditator setting aside any belief whose truth can be doubted, whether slightly or completely.
Descartes’ aim is to show that, even if we start from the strongest possible skeptical position, doubting everything, we can still reach knowledge.
The doubt is “hyperbolic" (exaggerated), and used only as a philosophical tool; as Descartes points out: 
“no sane person has ever seriously doubted these things."
Descartes starts by subjecting his beliefs to a series of increasingly rigorous skeptical arguments, 
questioning how we can be sure of the existence of anything at all.
Could it be that the world we know is just an illusion?
We cannot trust our senses, as we have all been “deceived" by them at one time or another, and so we cannot rely on them as a sure footing for 
knowledge.
Perhaps, he says, we are dreaming, and the apparently real world is no more than a dream world.
He notes that this is possible, as there are no sure signs between being awake or asleep.
But even so, this situation would leave open the possibility that some truths, such as mathematical axioms, could be known, 
though not through the senses.
But even these “truths" might not in fact be true, because God, who is all-powerful, could deceive us even at this level.
Even though we believe that God is good, it is possible that he made us in such a way that we are prone to errors in our reasoning.
Or perhaps there is no God—in which case we are even more likely to be imperfect beings (having arisen only by chance) that are capable of being 
deceived all the time.
Having reached a position in which there seems to be nothing at all of which he can be certain, Descartes then devises a vivid tool to help him to 
avoid slipping back into preconceived opinion: he supposes that there is a powerful and evil demon who can deceive him about anything.
When he finds himself considering a belief,
he can ask: "Could the demon be making me believe this even though it was false?"
and if the answer is "yes" he must set aside the belief as open to doubt.
At this point, it seems as though Descartes has put himself into an impossible position—nothing seems beyond doubt, 
so he has no solid ground on which to stand.
He describes himself as feeling helplessly tumbled around by a whirlpool of universal doubt, unable to find his footing.
Skepticism seems to have made it impossible for him even to begin his journey back to knowledge and truth.
The First Certainty.
It is at this point that Descartes realizes that there is one belief that he surely cannot doubt: his belief in his own existence.
Each of us can
think or say: "I am, I exist", and while we are thinking or saying it we cannot be wrong about it.
When Descartes tries to apply the evil demon test to this belief, he realizes that the demon could only make him believe that he exists if he does in 
fact exist; how can he doubt his existence unless he exists in order to do the doubting?
This axiom—"I am, I exist"— forms Descartes' First Certainty.
In his earlier work, the Discourse on the Method, he presented it as: "I think therefore I am", but he abandoned this wording when he wrote the 
Meditations, as the inclusion of "therefore" makes the statement read like a premise and conclusion.
Descartes wants the reader—the meditating "I"—to realize that as soon as I consider the fact that I exist, I know it to be true.
This truth is instantly grasped.
The realization that I exist is a direct intuition, not the conclusion of an argument.
Despite Descartes' move to a clearer expression of his position, the earlier formulation was so catchy that it stuck in people's minds, 
and to this day the First Certainty is generally known as "the cogito", from the Latin cogito ergo sum, meaning "I think therefore I am."
St.
Augustine of Hippo had used a very similar argument in The City of God, when he said: "For if I am mistaken, I exist"; 
meaning that if he did not exist, he could not be mistaken.
Augustine, however, made little use of this in his thinking, and certainly did not reach it in the way that Descartes did.
What use, though, is a single belief?
The simplest logical argument is a syllogism, which has two premises and a conclusion—such as: all birds have wings; a robin is a bird; 
therefore all robins have wings.
We surely cannot get anywhere from the starting point of just one true belief.
But Descartes was not looking to reach these kinds of conclusions from his First Certainty.
As he explained: "Archimedes used to demand just one firm and immovable point in order to shift the entire Earth."
For Descartes, the certainty of his own existence gives him the equivalent; it saves him from that whirlpool of doubt, gives him a firm foothold, 
and so allows him to start on the journey back from skepticism to knowledge.
It is crucial to his project of enquiry, but it is not the foundation of his epistemology.
What is this “I”?
Despite the fact that the First Certainty's main function is to provide a firm footing for knowledge, 
Descartes realizes that we might also be able to gain knowledge from the certainty itself.
This is because the knowledge that I am thinking is bound up with the knowledge of my existence.
So "thinking" is also something that I cannot rationally doubt, for doubting is a kind of thinking, so to doubt that I am thinking is to be thinking.
As Descartes now knows that he exists and that he is thinking, then he—and every other meditator—also knows that he is a thinking thing.
Descartes makes clear, though, that this is as far as he can reason from the First Certainty.
He is certainly not entitled to say that he is only a thinking thing—a mind— as he has no way of knowing what more he might be.
He might be a physical thing that also has the ability to think, or he might be something else, something that he has not even conceived yet.
The point is that at this stage of his meditations he knows only that he is a thinking thing; as he puts it, he knows only that he is, 
"in the strict sense only" a thinking thing.
Later, in the sixth book of the Meditations, Descartes presents an argument that mind and body are different sorts of thing—that they are distinct 
substances—but he is not yet in a position to do so.
Doubting Descartes.
This First Certainty has been the target of criticism from many writers who hold that Descartes' approach to skepticism is doomed
from the start.
One of the main arguments against it takes issue with the very use of the term "I" in "I am, I exist."
Although Descartes cannot be wrong in saying that thinking is occurring, how does he know that there is "a thinker"—a single, 
unified consciousness doing that thinking?
What gives him the right to assert the existence of anything beyond the thoughts?
On the other hand, can we make sense of the notion of thoughts floating around without a thinker?
It is difficult to imagine detached, coherent thoughts, and Descartes argues that it is impossible to conceive of such a state of affairs.
However, if one were to disagree, and believe that a world of thoughts with no thinkers is genuinely possible, 
Descartes would not be entitled to the belief that he exists, and would thus fail to reach his First Certainty.
The existence of thoughts would not give him the solid ground he needed.
The problem with this notion of thoughts floating around with no thinker is that reasoning would be impossible.
In order to reason, it is necessary to relate ideas in a particular way.
For example, if Patrick has the thought "all men are mortal" and Patricia has the thought "Socrates is a man", neither can conclude anything.
But if Paula has both thoughts, she can conclude that "Socrates is mortal."
Merely having the thoughts "all men are mortal" and "Socrates is a man" floating around is like two separate people having them; 
in order for reason to be possible we need to make these thoughts relative to one another, to link them in the right way.
It turns out that making thoughts relative to anything other than a thinker (for example, to a place or to a time) fails to do the job.
And since reasoning is possible, Descartes can conclude that there is a thinker.
Some modern philosophers have denied that Descartes' certainty of his own existence can do the job he requires of it; 
they argue that "I exist" has no content, as it merely refers to its subject but says nothing meaningful or important about it; 
it is simply pointing at the subject.
For this reason nothing can follow from it, and Descartes' project fails at the beginning.
This seems to miss Descartes' point; as we have seen, he does not use the First
Certainty as a premise from which to derive further knowledge—all he needs is that there be a self for him to point to.
So even if "I exist" only succeeds in pointing to the meditator, then he has an escape from the whirlpool of doubt.
An unreal thinker.
For those who have misunderstood Descartes to have been offering an argument from the fact of his thinking to the fact of his existence, 
we can point out that the First Certainty is a direct intuition, not a logical argument.
Why, though, would it be a problem if Descartes had been offering an argument?
As it stands, the apparent inference "I am thinking, therefore I exist" is missing a major premise; that is, 
in order for the argument to work it needs another premise, such as "anything that is thinking exists."
Sometimes an obvious premise is not actually stated in an argument, in which case it is known as a suppressed premise.
But some of Descartes' critics complain that this suppressed premise is not at all obvious.
For example, Hamlet, in Shakespeare's play, thought a great deal, but it is
also clearly true that he did not exist; so it is not true that anything that thinks exists.
We might say that in so far as Hamlet thought, he thought in the fictional world of a play, but he also existed in that fictional world; 
in so far as he did not exist, he did not exist in the real world.
His "reality" and thinking are linked to the same world.
But Descartes' critics might respond that that is precisely the point: knowing that someone called Hamlet was thinking—and no more than this—does not 
assure us that this person exists in the real world; for that, we should have to know that he was thinking in the real world.
Knowing that something or someone—like Descartes—is thinking, is not enough to prove their reality in this world.
The answer to this dilemma lies in the first-person nature of the Meditations, and the reasons for Descartes' use of the "I" throughout now becomes 
clear.
Because while I might be unsure whether Hamlet was thinking, and therefore existed, in a fictional world or the real world, 
I cannot be unsure about myself.
Modern philosophy.
In the "Preface to the Reader" of the Meditations, Descartes accurately predicted that many readers would approach his work in such a way that most 
would "not bother to grasp the proper order of my arguments and the connection between them, but merely try to carp at individual sentences, 
as is the fashion."
On the other hand, he also wrote that "I do not expect any popular approval, or indeed any wide audience", and in this he was much mistaken.
He is often described as the father of modern philosophy.
He sought to give philosophy the certainty of mathematics without recourse to any kind of dogma or authority, and to establish a firm, 
rational foundation for knowledge.
He is also well known for proposing that the mind and the body are two distinct substances—one material (the body) and the other immaterial (the 
mind)—which are nonetheless capable of interaction.
This famous distinction, which he explains in the Sixth Meditation, became known as Cartesian dualism.
However, it is the rigor of Descartes' thought and his rejection of any reliance on authority that are perhaps his most important legacy.
The centuries after his death were dominated by philosophers who either developed his ideas or those who took as their main task the refutation of 
his thoughts, such as Thomas Hobbes, Benedictus Spinoza, and Gottfried Leibniz.
Rene Descartes.
Rene Descartes was born near Tours, France, and was educated at the Jesuit College Royale, in La Fleche.
Due to ill-health, he was allowed to stay in bed until late in the mornings, and he formed the habit of meditating.
From the age of 16 he concentrated on studying mathematics, breaking off his studies for four years to volunteer as a soldier in Europe's Thirty 
Years War.
During this time he found his philosophical calling, and after leaving the army, he settled first in Paris and then in the Netherlands, 
where he spent most of the rest of his life.
In 1649 he was invited to Sweden by Queen Christina to discuss philosophy; he was expected to get up very early, much against his normal practice.
He believed that this new regime—and the Swedish climate—caused him to contract pneumonia, of which he died a year later.
Key works:
1637 Discourse on the Method,
1641 Meditations on First Philosophy,
1644 Principles of Philosophy,
1662 De Homine Fuguris.
IN CONTEXT:
BRANCH: Epistemology,
APPROACH: Rationalism.
BEFORE:
4th century bce Aristotle argues that whenever we perform any action, including thinking, we are conscious that we perform it, 
and in this way we are conscious that we exist.
c.420 CE St.
Augustine writes in The City of God that he is certain he exists, because if he is mistaken, this itself proves his existence—in order to be 
mistaken, one must exist.
AFTER:
1781 In his Critique of Pure Reason, Immanuel Kant argues against Descartes, but adopts the First Certainty—“I think therefore I exist”—as the heart 
and starting point of his idealist philosophy.
It is necessary that at least once in your life you doubt, as far as possible, all things.
Rene Descartes.
