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Rationalism cogito ergo sum. What is Rationalism? So, you hear all the hype about Rationalism and wonder what exactly it is. Rationalism involves the.

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Presentation on theme: "Rationalism cogito ergo sum. What is Rationalism? So, you hear all the hype about Rationalism and wonder what exactly it is. Rationalism involves the."— Presentation transcript:

1 Rationalism cogito ergo sum

2 What is Rationalism? So, you hear all the hype about Rationalism and wonder what exactly it is. Rationalism involves the use and application of reason to derive knowledge. We can ascertain truth by thinking and by the process of reflection alone. Rationalism involves these key principles: 1.A priori knowledge: There are true forms of knowledge, independent of experience. 2.We all have innate ideas. 3.Something has to be true, because it cannot be otherwise. Adapted from

3 Einstein’s puzzle There are five houses. The Englishman lives in the red house. The Spaniard owns the dog. Coffee is drunk in the green house. The Ukrainian drinks tea. The green house is immediately to the right of the ivory house. The Old Gold smoker owns snails. Kools are smoked in the yellow house. Milk is drunk in the middle house. The Norwegian lives in the first house. The man who smokes Chesterfields lives in the house next to the man with the fox. Kools are smoked in the house next to the house where the horse is kept. The Lucky Strike smoker drinks orange juice. The Japanese smokes Parliaments. The Norwegian lives next to the blue house. NOW, MATCH THE PEOPLE TO THEIR RESPECTIVE HOUSES, HOUSE COLOUR, DRINKS, PETS, AND BRAND OF CIGARETTES SMOKED. GIVE REASONS FOR YOUR ANSWERS. 1.Each of the houses is painted a different colour. 2. Inhabitants are of different nationalities. 3. Inhabitants own different pets 4. Inhabitants drink different beverages. 5. Inhabitants smoke different brands of American cigarettes.

4 Solution to the Einstein puzzle House12345 ColourYellowBlueRedIvoryGreen Nationalit y Norweigia n UkrainianEnglishm an SpaniardJapanese DrinkWaterTeaMilkOrange juice Coffee CigarettesKoolsChesterfie ld Old Gourd Lucky strike Parliamen t PetFoxHorseSnailsDogZebra

5 How does the Einstein puzzle link to Rationalism? The answer lies in deductive reasoning. By using your logic and reasoning to match each respective characteristic to an individual, you have applied deductive reasoning! Deductive reasoning The process of reaching conclusions through inference from a priori postulates.

6 Inductive reasoning Inductive reasoning involves drawing general conclusions from specific examples. E.g. A European naturalist observes European swans. He has seen thousand of white swans for many years, so his logical conclusion is that all swans are white. We now know that there are black swans in New Zealand and Australia. The problem of generalising is called the ‘problem of induction’. In practice, we usually draw conclusions from limited evidence. It seems reasonable sometimes (e.g. the sun has risen everyday, so it will rise again tomorrow), but sometimes it does not appear so. Thus, it is important to sieve out evidence which supports a conclusion and when it does not. (i.e. Which inductive logic is reliable and which will lead us astray?)

7 Criticism of Descartes’ argument Descartes in his meditations basically sets out to search for certain fundamental “truths” which he calls “Principles of philosophy”. The “truths” that he tries to prove are: Existence of the self Existence of God The senses cannot be trusted The method that Descartes use to deduce these “truths” is unique. He rejects as false anything in which he can imagine the least doubt in order to see if whether, after this process, something in his beliefs remains entirely indubitable. He rejects as false all reasonings that he had taken to be demonstrations because humans are prone to make mistakes and he is prone to err as any other. He pretends that all the things that had ever entered his mind were no truer than illusions of his dreams.

8 He says however that while he was doubting all of this, it was necessary for him to be “something” in order for him to do so. Therefore, he takes “ I think, therefore I am” as the First principle of philosophy that he is seeking and using this as a base, he sets out to search for other such “truths”. For something to be true however, there should be no element of doubt associated with it whatsoever i.e. it should be entirely indubitable. Descartes meditations have four major arguments, cornerstones that are extremely important: The God argument The evil deceiver argument The dream argument The wax argument Our aim today is to critically evaluate this argument and try and ascertain as to what extent it can be “believed”.

9 I think, therefore I am Descartes admits that he cannot be entirely certain about the existence of body or the world around him. He says however that it is impossible for him to pretend that he does not “exist” at all and that on the contrary, from the very fact that he is thinking of “doubting” the existence of other things, it is very certain and evident that he exists. He says that “thought” is the only way by which he can ascertain his existence. He defines himself as “A substance, the whole essence or nature of which is simply to think, and which, in order to exist, has no need of any place nor depends on any material thing”. He also talks about the soul saying that, “I, that is to say, the soul through which I am what I am, is entirely distinct from the body and is even easier to know than the body, and even if there was no body at all, it would not cease to be all that it is”.

10 The God argument Descartes considered “doubt” to be an imperfection. He says that a “perfect” being will possess “absolute” knowledge and hence, will not “doubt”. He, on the other hand, has doubted everything from his very own existence to that of the world around him. This is an indication of “imperfection” in him. Descartes thinks of something more perfect than him. The source for these thoughts about a “perfect being” and perfection must come from a nature more perfect than him. It is a contradiction to say that something more perfect should follow from something less perfect. It is also a contradiction that something comes from nothing.

11 The God argument Pt. 2 He believes that other things such as the heavens, earth, light, heat, etc. are in no way superior to him. They are in him because of his “imperfections”. He says that there is only one Supreme Being, a perfect being that within itself possesses all the perfections of which he can have any idea, this being he calls “God”. He also says that since he knows of some perfections that he does not possess, he is not the only being that existed i.e. there is a “Supreme God”. He says that if he were alone and independent of everything else, he should be able to possess all that he knew he lacked and thus himself have all the perfections he could observe in God.

12 The God argument Pt. 3 He also says that even if he were in an prolonged dream, there was still the possibility of these thoughts entering his mind because of God. He then says that there is a clear distinction between sensible and corporeal nature. God however could not be composed of both these natures because if God were composed, he would “depend” on these natures. Dependence, however, Descartes considers to be a defect and since God cannot have any defects, God is not composed. However, he says that he and any other (if any) intelligence in this world is composed and depends on God so much that they cannot exist without God at all.

13 The God argument Pt. 4 (Analysis) The most important flaw in his argument is that he does not define the term “perfect”. In his argument, there is clearly no “absolute perfection” since he speaks of greater and lesser perfections. Since his definition is so unclear, we can also question his statements about light, heat, etc. being imperfect. He does not explain why it is impossible for something to “more perfect” to come from something “less perfect”. E.g. Humans evolved, (in other words coming from apes), creatures that are “less perfect”. Humans also depend on birds and animals for food, creatures that are “less perfect” than humans.

14 The God argument Pt. 4 (Analysis) He says that God possesses all the perfections that he can think of. He discounts the possibilities of other perfections existing and therefore the existence of other “Gods”. He also says that if he were alone and independent of all things, he would be able to possess all the perfections he knew of. He does not, however, explain why. He also does not explain why any other “intelligence” in this world has to depend on God for it to exist.

15 The Evil Deceiver argument What if the supreme being “God” is not benevolent but malicious? He misleads individuals in any way possible such that everything they sense is not real but merely fallacious sense-data. In that case, one cannot trust what one senses and can only rely upon irrefutable logic and reason, rather than the possibility that one could trust one’s senses because of his or her absolute presence a real world created by this God. Even so, “I think, therefore I am” cannot be contradicted, because if this being indeed is deceiving an individual, there must be an individual present to be deceived.

16 The Evil Deceiver argument Pt. 2 Descartes casts doubt into what he senses: colours, sounds, touch. Descartes proposes the use of logic to uncover truth, rather than relying on his senses. He discounts the possibility that the “Evil Deceiver” can manipulate minds in such a way that what he thinks is in fact not his thoughts, but artificial thoughts planted into his head by this evil being. This would make his vaunted logic totally invalid. Alternatively, if there indeed is a supreme being, Descartes would not have the free will to reach conclusions of his arguments but merely have believed he did. Also, it is possible that he is deceiving himself through a dream, thus:

17 The dream argument The sane and the insane are separated in what their senses perceive. Likewise, the thing that separates those dreaming and those who are awake is the fact that those dreaming sense something imaginary (Contrary to the apparent absolute truth). Everything which we sense while awake can be sensed through dreaming. So, it is possible to have a “false awakening”. Some sensations which are experienced within dreams, for example, flying without wings, are impossible within what we consider to be “real”.

18 The dream argument Pt. 2 Descartes argues that for one to imagine something, it must have been present before in thought. If God had not existed, Descartes would not have been able to imagine such. Then, is it possible that some of the things which are apparently impossible and beyond the boundaries of what we consider to be absurd do in fact have roots in truth? If so, we can perceive dreams to be real-life.

19 The dream argument Pt. 3 To conclude, even though what we sense seems more real when we think we are awake than when we think we are asleep, it is possible for our sense to be fooled. We cannot trust them completely. The absence or presence of an eternal dream cannot be proven or disproved absolutely, but because this is only pertinent to corporeal objects, he can separate what he perceives from what he reasons out through logic and thus they will not affect his senses. Again, there is the possibility that Descartes is indeed eternally dreaming and that this dream warps his logic and thought in such a way that he does not sense it. Thus, what he supposes to be logical is, in fact, not.

20 The wax argument Descartes thinks that the piece of wax before and after melting is the same piece of wax. Consider wood, which will burn if held in a fire and become ash. Can this still be considered wood? How about when oxygen and hydrogen are mixed and made to combust? Water is formed. Is water hydrogen or oxygen? No doubt it composed of its discrete parts, but can it be said to “be” them? Consider a ship. All its parts are replaced one by one and these old parts are stored in a hermetically-sealed warehouse, such that eventually all the parts of the ship are replaced. Old parts are then gathered to build a new ship. Which is the real ship?

21 The wax argument Pt. 2 Descartes did not mention what exactly is “the same” either. The concept of “sameness is extremely important to Descartes’ argument, but it is not clarified in any way. By stating that human perceptions are required to fully uncover the truth of the wax, Descartes ignores the possibility that animals do not exist, or animals that have the mental capabilities far exceeding his own. If so, what he understands of wax would be inferior and flawed. Animals can also perceive wax to be the same thing as he does. All these are possible, and if were true, would contradict his statement that human understanding is required to more fully comprehend the structure of wax.

22 The wax argument Pt. 3 Descartes also judges that wax infinitely mutable because of conscious understanding on the piece of wax’s properties. His imagination cannot think of what is possible because he considers himself unable to imagine the infinite possibilities of the forms wax can take. However, he does not/cannot absolutely prove that there is no other organism considered to be equally perfect or less perfect compared to himself. That organism can possibly comprehend at his level, or even comprehend the wax’s mutability due to its IMAGINATION.


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