There are also some other principles that convince us to think that something is true and certain. First, anything that can be doubted should be doubted according to Descartes. In relation to this, we are -the human beings- sure of ourselves as thinking being not as physical beings so that we cannot doubt the contents of our thoughts. Secondly, if something becomes distinct and clear by being divided into its simplest part, it should be true. Descartes is sure about that he thinks and therefore he is because according to him this phenomenon is a single thing that cannot be divided.
“Is there a God or not?” The existence of God also takes place in the third meditation of Descartes in the name of certainty. In this sense, Descartes tries to find a way to go from consciousness to objective validity and his criteria is to find clear and distinct ideas again. Regarding to this way, Descartes uses introspection method which is paying attention to your own consciousness. He claims the existence of God in such a way that is innate idea. An innate idea is something that is in you, not external; hence, it cannot be created by you. Also, Descartes thinks that he is a substance or a pencil is a substance that each of them exists independently. Then, Descartes is thinking thing but the pencil is not, but how can it possible for both to exist? Descartes explains this contradiction with respect to the classification of them, i.e in so far as they represent substances. Since Descartes is nothing but a thinking thing, he has merely modes of substance and he thinks that the substances are contained to him eminently. So, just one idea comes to his mind which is God because he thinks that he cannot invent a greater idea than him. Finally, God necessarily exists because it cannot be otherwise.
If we ever gain certainty in our knowledge, we should not start from the object because its quality, physical properties are assumed by us as a habitual behavior. We assume our perceptions are certain then we assume what we see is real. By doing so, we will never reach certainty according to Descartes.
Naturally, every assertion has to confront its opponent. Anyway philosophers could come closer to find the meaning of life and to find the answers of problems such as certainty. David Hume is one of the philosophers who tried to answer all these questions that Descartes tried to deal with. “Where does the origin of ideas come from?” Descartes claims that if something is a thinking thing then, it has to be certain. Also, he says that we cannot rely on the perceptions and senses because they deceive us. The only senses which are very clear and distinct can be certain. In relation to this, Descartes separates the thinking and mind by giving emphasis on the thinking not mind. On the other hand, perceptions should be divided into two classes because they have different degree of force and vivacity according to Hume. One of the perception is “thought or ideas” and the other one is “impressions”. Ideas are less lively perceptions but impressions are the origins of our ideas which are the first perceptions that grab our attentions. Senses cannot deceive us because they are meaningful because perception of mind is a copy of perception of senses. From Humes’s position in fact, we should give more emphasis on mind indirectly.
If something exists independently, it should be real and certain says Descartes. So, it defines a stone or a human as a certain beings but Hume claims that if there is not impression that the idea derived from, the term is meaningless. As an example of this, he considers a blind born person. This person cannot know the blue color because he has not the first impression. Thus, we cannot think of a different shade of blue, if the origins of ideas are derived from impressions. On the other hand, Descartes would say that if I am certain as a thinking thing that blue exists then it should exist in the nature but Hume reduces the existence of the things into impressions. Thus, we cannot say that every substance is certain, we cannot be sure of that.
Descartes says that basis of our knowledge is our reason and he also had said that he is a thinking substance, and that physical objects are extended substances. So the notion is that substances are the primary beings, and that they have properties such as thinking. However, Hume abandons this idea. According to him, when we examine our idea of an individual thing, all that we find is the simple ideas which go together to make a complex idea. He takes our attention from substances toward relations which are that philosophy should consider. If we think an apple, we think the one which is a deeper red or the one that is closer to our hand. ( Impressions) The most important relations of ideas are the cause and effect because this relation goes beyond our senses and informs us whether something exist or not ,even we do not see and feel. The growing of the crops in the fields is something beyond our present experience, according to the relation of cause and effect, we can say that the sun will make the crops grow. The sun is the cause and the growing crops is the effect. Therefore, when Descartes explains the fall of pen with reasoning, he does not have a point because from Hume’s point of view, pan will fall because of gravitational force and this causal effect is coming from experience not by reasoning.
The existence of God is tried to be answered by Hume and Descartes. Descartes made analysis to prove the existence of God by using inside as a starting point but Hume prefers to trust his perception i.e, he takes outside as a starting point.
“Descartes decided soon enough that he was not alone, that along with his own existence, the existence of God is certain. And he could use the existence and nature of God as a basis for claiming knowledge about the other things making up the material world. Further, he placed his faith in rational intuition, a kind of mental vision which recognizes the truth in clear and distinct perception. Hume diagnosed mental "vision" as akin to hallucination.”
Since all knowledge is based on experience, and experience does not give us any knowledge that is certain. Thus, all knowledge is probable only. This is the basic principle of Hume’s philosophy. He was deeply affected by his skeptical doubts and he has some point as a counter argument of Descartes. Descartes says “I think therefore I am” and he deals certainty with thinking thing. Also, we know that there are animals in the nature that are lack of thinking . So, we are certain that these animals are vivid and are lack ok of thinking because of this they should not exist. If we agree with this assertion, we would be definitely wrong because we experience the existence of these animals.
Suddenly, you realized that you have still some ideas even though you pushed your thoughts away from your mind. And then you assume that there is a superior power that puts these thoughts in your mind named God. Also, you are certain of its existence. No one can be sure of something when he/she is in a situation of uncertainty. The ideas that take place in your mind, when you are abstracted yourself from any substance can only be the imaginations of your mind. “Nothing is more free than the imagination of man: and though it cannot exceed that original stock of ideas…” ( Enquiry concerning Human Understanding -Part 2-p.124)
How do we know the future events will be resemblance of the past? According to Hume we have to believe that similar causes have similar effects, nature is uniform and the future will resemble the past because of the custom. We can always imagine that the past events will duplicate themselves in the future. For example, I observed that the event A was followed by B and it has happened for many times. Then, I know that whenever A happens, B will either. In relation to this, we should reject the idea of habitual behavior of humans that Descartes offers. In fact, our beliefs are rather conditioning. The reason of why B happens after A is not simply reasoning but conditioning.
www-philosophy.ucdavis.edu/phi001/humelec.htm •
