Descartes invented the graph (Cartesian co-ordinates is an adjective of his name), analytical or co-ordinate geometry and numerous other mathematical principles.
Likewise, in philosophy, Descartes is considered the father of modern philosophy. He believed in this vision: there is nothing that cannot be obtained by logical and rational conclusion.
Descartes came to this conclusion by observing a few very important concepts in Mathematics. He observed that everything in mathematics can be broken down to basic elementary logical steps which have a simple, straight-forward, logical conclusion. For example, the shortest distance between two points is straight line. He then used this conclusion as the premise for subsequent arguments which had an equally rational and logical conclusion. Following our preceding example, the time taken to travel between two points in a straight line must be the minimum.
Descartes loved this form of argument which is prevalent in all mathematics. And he rationalized thus-: if this form of argument can be applied to mathematics and science, why cannot it be applied to other fields including philosophy? And that is exactly what he attempted to do.
He contemplated three different forms of thinking. The first form is the power of observation by sight. However, he found out that observation by sight is not entirely reliable. The building that looks red in the morning looks black in the evening. If so, then what is the actual colour of the building? Is observation by site to be relied upon for such scientific observations? He decided no and went on to experiment with other methods.
The second method he decided to delve into is his consciousness. Can I be absolutely certain that what I am doing is actually what I am doing and not what I am dreaming of doing? No! I could not be absolutely certain of that fact. At times, it appears to me that I am doing something just to find out that I was actually dreaming of accomplishing it. In other words, it was nothing more than a vivid dream.
However, I must admit that the occasions on which I have actually managed to remember my dreams upon waking up are so infrequent and far between that I can count them with one hand.
To continue on Descartes arguments, unable to come up with any other arguments an in utter despair, Descartes modified the second argument: What if the errors and illusions I have are not my fault but are due to some higher order which controls them? What if the higher order is the ultimate authority and that I have no say over what eh decides? What will happen then?
If that is the case, then the best solutions would be to assume that what your consciousness says is true. I may have had some experiences and m not sure if the experiences occurred in reality or in a dream. However the one thing I am sure of is that I had an experience. This is a certainty which cannot be refuted and thus must be proven true, like an axiom. It this follows that the consciousness is a fact and so is the notion that I exists since consciousness cannot exist without the existence of being and consequently, the existence of oneself and of consciousness are interlinked and interdependent on each other. Descartes came up with beautiful and elegant phrase for it â€˜cogito ergo sumâ€™ or â€˜I think therefore I amâ€™.
Following this conclusion towards its ending, we know that we are not perfect in anyway but on the contrary, are filled with flaws. But we also know what an ideal human being should be, namely, perfect and ideal in every sense and inextricably linked with his consciousness as a human being. We usually denote this idea human being as God. Thus we presume that god exists [Descartes extrapolated this to knowing that god exists, how do you come to that conclusion?]. Provided we do our job, god will take care of the outcome, which he will do by presenting me with an outcome which my consciousness clearly recognizes as true.
This is very similar to the Hindu philosophy; do your karma and whatever the result is the one you have worked for. In other words, reap as you sow. this raises an important question, did Descartes come into contact with Indian philosophy? If so, then how? Wherefrom? However, this is besides the scope of this article as answering this question will lead us to the history of civilizations.