How did Monsieur Rene Descartes come to the conclusion "I think therefore I am"?

Question

My Maths teacher used to say that he doesn't find anything amazing with the saying "I think therefore I am" (Cogito ergo sum) but he always said it is how he got to the saying that is interesting.My question here is how did Rene Descartes get to this statement or rather why did he say it?

Answer 1

The saying is not what is interesting. This is a quote where Descartes was trying to prove the reality of his existence. It is part of the metaphysics section of philosophy, which considers what is real and what is not real. So anyway, the ideaology behind"I think, therefore I am" is that since you are capable of real thought, then the thing that is producing the thought (which would be you)  is real. Basically, it means, since I can perform real actions, then I myself must be real.

Answer 2

Decartes was a Renaissance Man and men of the "modern" science at his time were realizing that many of the views of the ancients such as Plato were not perfect and produced only argument and doubt.  He used a system of "exaggerated doubt" in his quest for knowledge.

He decided to banish everything from his mind to see if he could find "what was true" and these were his rules:

1.  Never to accept anything as true tht I did not know to be evident (DOUBT)

2.  To divide each of the difficulties that I was examining into as many parts as might be possible in order to best solve it (DOWN TO BASICS)

To conduct my thoughts in an orderly way beginning with the simplest objects and the easiest to know in order to climb gradually METHODICAL CLIMB

4.  To make such complete enumerations and such general reviews that I would be sure to have omitted nothing (PAINSTAKING REVISION)

He had felt that the only certain knowledge was in Mathematics so he set his mind in training examining algebra beginning with the most simple and general rules.  He could be assured he was using just his reason for his findings.  He was 23.  He wanted to tread slowly and gain wide practice in the application of his "method".

In his travels over 9 years he found that most knowledge could be doubted.

His Meditations are a living enactment of his philosophical thought.  An order of discovery.  In the Discourse and Meditations he sets down his thoughts on how to gain knowledge of what is true.  To find certainty he "Must keep away from everything of which "I can conceive of the slightest doubt just as if I knew that it was absolutely false".  He wasn't at all sure he would find anything and that perhaps there's nothing certain in this world.

In the opening paragraphs on the First Meditation Descartes argues with himself about the belief that is based on sensory perception.  Since it is possible to be deceived by his senses in the form of dreams etc and optical illusions for example "Is it not possible that his senses always deceive him?"  Because there is no conslusive evidence as to whether he is in a sleeping or waking state "He must at this stage doubt all sensory belief.

He even casts the concept of God out of his thoughts.

He gets to the point where nothing is certain by applying his method of Systematic Doubt.  He cannot even be certain that he has a body.

He then makes his "Breakthrough"

Throughout his meditations he discovers his first great certainty.  HE HAS BEEN THINKING AND DOUBTING.  About his senses, about his body, God, evil many things.  He decided that while he was thinking and doubting he MUST HAVE EXISTED. He asks himself 'WAS I THEREFORE PERSUADED THAT I DID NOT EXIST?  NO INDEED :  I EXISTED WITHOUT DOUBT BY THE MERE FACT THAT I THOUGHT AT ALL.  That is he must exist to be deceived

So his first piece of certain knowledge:  I THINK THEREFORE I AM

Can he doubt that he is sitting in his dressing gown by the fire (YES, he could be dreaming)  So using his method of exaggerated doubt his body may be an illusion BUT HE THINKS (THIS makes mind more certain than body)

From this point of he goes on "But I who am certain that I am do not yet know clearly enough what I am"  He knows he can be deceived about having a body so what is he?" - Not an animal wih a body but a thing that thinks.

All knowledge must begin with awareness of one's own existence:  A Consciousness - a Thinking Thing.  This was an extremely important feature of his thought - It had an enormous influence on all subsequent

philosophical thought  Most Philosophers since Descartes have attached importance to the 'THEORY OF KNOWLEDGE"

In seeing if he could gain knowledge of the physical world through evidence of "sensory" experience Descartes conducted his WAX EXPERIMENT where he melts some beeswax and comes to the conclusion that through all the changes in the melting (like loss of smell and loss of the original colour and becoming liquid he asks himself DOES THE SAME WAX REMAIN AFTER THIS CHANGE AND THE ANSWER IS YES and that is the power of his thinking that knows this to be true.  His sole power of judgement knows the Wax to be Wax.

Answer 3

You Know it dont af make me laf.... I have just been in philosophy and its full of guys asking questions about religion and poetry and all sorts and here is you - in anthropology asking a philosophy question.

Descartes was working on the problem of 'what is it that I can really know?' he peeled back the layers, with each layer showing how that layer can lead to delusion or illusion. However the one thing he could not doubt was that there was someone doubting (thinking).

Thats when he formulate "I think therefore I am"

Answer 4

Because life is real, only when YOU are...

Answer 5

The whole thing that comes from is:

Statement 1, therefore statement 2, therefore statement 3.

Which means that:

Statement 1, therefore statement 3.

In this case, I think it was:

I think, therefore I can (am able), therefore I am.

He was saying that because he has conscious though, he is able to do things of his own will, therefore he is alive/exists.

If things are not able to think consciously (inanimate objects), then they are not alive.