In this essay, I am going to evaluate Moore’s and Russell’s proof of the existence of external world. I will first outline Moore’s argument and Russell’s argument respectively. Then I will point out the difference in the scope of claim in the two arguments. Moore’s argument asserts a smaller scope of claim than Russell’s, thus it is more defendable. Furthermore, I will propose counter examples to nullify Russell’s argument. At last, I am going to propose my proof to the existence of external world to address the shortcomings in both Russell and Moore’s argument.

On the surface, Moore’s argument is surprise simple. It is so simple that it does not seem to be very convincing. His argument can be illustrated as the following. By holding out two hands, here is one hand and here is another hand. There are two hands exists in front of you. If those hands exist, which is something you cannot deny, there must be external world. [1-p451]

Let’s us understand Moore’s claim a little bit more. Moore’s claim is actually an argument to convince a skeptic who does not believes there is an external world but maintain the belief that there is still an external mind outside of his own mind. In another word, to begin with he has to at least believe that there is other mind, who is trying to convince him that there is an external world, already exists outside of him. Moore’s claim will not work on soloist who does not even believe there is anything outside of his own mind. Moreover, Moore’s claim is based on Kant’s early doubt that “the existence of things outside of us … must be accepted merely on faith, and that if anyone thinks good to doubt their (here, their refer to the external world, not those people) existence, we are unable to counter his doubts by any satisfactory proof.” [1- p439]. Most important of all, Moore’s claim does not survive Descartes style of self-meditation scrutiny. Moore believe there exists an external world and convince the other minds he experience in his external world to believe there really is an external world, but he can never proof to himself that he is not a sole existence that all the external world he experience are merely a product of his own mind.

Moore’s argument is pretty straight forward. He is playing word games on Kant’s argument by separating the definition of the terms use by Kant. He redefines “things outside of us”, “external things” and “things external to our mind” as three separate terms. (Notice that that he uses the term “things outside of US” instead of “things outside of ME”.) He excluded transcendent things from his argument, since that belongs to the department of metaphysics. Then he flipped the argument to equate “external things” to “things not internal to our mind”. Notice this slight change of term is the slate of hand he played to separate “things that can meet in space” from “physical objects” and here is he introduced the term “present in space” which supposed to have a lesser definition than “things that can meet in space”. He used a few examples like shadows, after image to illustrate his points, but I am not going to repeat the arguments here due to the limitation of space. Now, here he plays the finally trick, he used the “two hands” as a common experience shared between two different minds, which the skeptic cannot deny. Since there is a gap between the two minds and now there is a common experience come form that gap, there must be something existence between the two minds originate that experience, so the external world must exist.

Let’s move on to Russell’s argument, if that is qualified an argument. First of all, Russell’s claim is more ambitious than Moorse’s. Russell actually goes one step more to define the nature of external world, which is the existence of matter. Moorse is smart to leave the external world remains undefined which gives him more room to play with his definition tricks. Instead of arguing for the existence of matter, Russell simply makes the instinctive belief assertions without even bother to argue for it. To begin with, one cannot doubt his own existence and the existence of the sense data he experienced. Russell is quite frank to admit that “we can never prove the existence of things other than ourselves and our experience” [2-p.14], then he immediate follow by asserting that “although this is no logically impossible, there is no reason whatever to suppose that it is true.” and appeal to the common sense hypothesis to assert there are external objects that cause our sensations. Here he had commit the two fallacies. First, the appeal to common sense is begging of question. Second, even given that we can indeed somehow rule out the soloist possibility, his so-call argument still suffered from the false dilemma fallacy. He assumes that if we can rule out the soloist hypothesis, our sense data must come from physical objects, but he forgot the origin of experience can skipped the existence layer and come from the transcendent layer directly. For practical reason, we may operate on the “external object exists” instinctive belief proposed by Russell, but he should at least compare and evaluate all alternatives instincts before concluding his particular version of instinct is most simple thus should be the most possible solution.

In [2-p15] and chapter 3, Russell uses more examples to illustrate his instinctive belief of the existence of external object. In [2-p15], he uses the existence of a cat that is independent of his perception as an example. He thinks it is quite natural to think that a cat will continue to exists and feel hungry regardless of his sense-data. There is a famous counter example which is also a cat, Schrodinger’s cat. According to Quantum theory, the wave equation is only collapse at the moment of observation. Strictly speaking, Schrodinger’s cat are free to seize its existence when there is no observer, except that once when it is being observed, its state variable collapse to a known state and catch up with what supposed to happen during the unobservable moments. The Schrodinger’s cat does not sound nature to most people, but it conforms to the laws of quantum physics. Therefore whether something sounds nature or not cannot be used to justify the intrinsic belief. In chapter 3, Russell uses the common between public space and private space to argument for his existence of matter. I can nullify his arguments with two terms, “Virtual Reality” and “Augmented Reality”. In virtual reality, there is no public space and each one’s private space is truly private to him. In augment reality, although there still a public space, but the sense data of the public space can be augmented and altered before it arrive at the private space. In addition, Russell argues that a blind man cannot experience light. With the latest technology, the vision chip, a blind can actually experience light more or less like a seeing person although he never experience lights. The vision chips implanted in his retina stimulate the visual nerve to send image to the brain. In theory the whole visual process can stay digital and electrical without anything related to light. Therefore light must be something that can be reduced and transformed into a set of computer equations and can be recreated using digital processors.

Both Moore and Russell did not give a satisfying proof of the existence of external world to a soloist. I am going to propose my solution in the last paragraph in an attempt to bridge the gap left open in Moore and Russell’s argument. My proof that I am not a lone existence in this world is very simple. If I am alone in this world, no one is going to mark my philosophy paper and I will have no reason to write it. The very fact that I am writing this philosophy paper is the proof that I am not alone in this world, which imply there must exists an external world. Now, assume that there is a philosophy professor who is marking this philosophy paper. The very fact that he is marking this paper also is a proof of the existence of an external world; otherwise he has no reason to mark this paper. In fact, if there is no external world, why would anyone bother to read a paper trying to proof the existence of the external world? Therefore the mere existence of this philosophical paper on its own is the proof of the existence of the external world. Q.E.D.

Reference:
[1] Paul K. Moser and Arnold Vander Nat, Human Knowledge Classical and Contemporary Approaches, 2003, Oxford Press
[2] Bertrand Russell, The Problems of Philosophy, 1912, Feedbacks

這個學期我在大學修讀了我的第一門哲學課﹐是PHIL300哲學入門。讀這科可以說是純為興趣﹐今個學期我已經做完碩士論文等畢業﹐橫豎有公司交學費不要浪費﹐便找門有興趣的課來讀讀。這門課是三年級的課程﹐不過是以非哲學本科生為對象開設﹐若已經讀了一年級哲學入門課﹐便不能再讀這科取學分。雖說是哲學入門﹐其實嚴格來說只是認知論(epsitemology)入門﹐因為選用的課本和教授哲學家的想思﹐也都是屬於這哲學三大分支之一。其他兩門分支是形上學(metaphysics)和價值論(value theory)

認知論就是探討知識的學問﹐去理解究竟知識是什麼﹐人如何可以獲得知識﹐應該怎樣去分辨知識的真假﹐及至科學的定義﹐什麼才算是科學理論等等。聽起來好像很無聊的東西﹐但卻能夠幫助我們明白和認識清楚世界﹐知道很多我們平時以為天公地義的事﹐背後原來殊不簡單﹐一個不小心﹐很容易就會給存心欺騙的人矇閉。最重要的是這門課讓我大開眼界﹐發現以前聽過一磷半抓的思想學說﹐每個也有出處跟據﹐絕非所見般簡單。例如Matrix這套電影的世界觀好像很創新﹐發現原來只是抄二百幾年前﹐完美經驗派哲學家Berkeley的想法﹐用新的包裝重新推出來拍戲。

這課的形式是每個星期的一堂﹐紹介一名死鬼哲學家以及他的思想學說。由啟蒙時代的Descarte開始說起﹐先後介紹理性主義和經驗主義的代表人物﹐再到把兩者整合哲學中的巨人康德(Kant)﹐還有後來的實用主義和自然主義﹐再到組成二次大戰後的維也納圈的邏輯學派﹐和其相對的科學哲學理論。其實也不是全部哲學家也是死掉的﹐最後幾堂也有教還在生的人。最出名就是發明Paradigm Shift這個名詞的Thomas Khun﹐這個字現在給那些商管人用到爛用到悶﹐最初的本意其實原來是另一回事。

對我來說課堂並不沉悶﹐因為每一名哲學家的思想對我也是新奇的﹐也都刺激我去思考一些以前沒有想過的問題。教授不算是太悶﹐不過就欠缺一點互動討論的積極性 ﹐如果不是包括我在內的幾個學生問問題﹐他可以講完一個哲學家講另一個不停教下去﹐也不理我們是不是真的明白。這課並不難讀﹐也不用花很多時間﹐可能其一是我是求學不是求分數﹐其二是每個星期我溫習時﹐在咖啡店當是看課外書地享受閱讀。平均每個星期要看五十多頁﹐大慨用一個晚上兩個小時就足夠了。這科只有兩份功課﹐是兩篇千多字的文章﹐外加期中考和大考。不知是不是我讀理性寫不慣文科的文﹐雖然我好肯定我完全明白課文內容﹐兩篇功課和其中考也是只得個C+﹐相信大考的分數也不會例外。這科是我讀大學以來﹐成績最差的一科﹐文科真的比理科難拿高分。

選讀這科的人大部份是鬼仔鬼妹﹐也有幾個同學和我一樣是上了年紀的學生。亞洲人特別是香港人﹐大慨對這種不能賺錢﹐沒有實際用途的學科不感興趣。至於在一班三十幾個同學中﹐有幾多個是對哲學有興趣而讀﹐又有幾多個是因為以為這科容易取得必修選項的學分而讀呢﹖大慨整個學期堂一句聲也不出的那些是後者﹐會一邊聽書一邊嘴嚼內容﹐總會找機會去問教授問題﹐尤其是以問到他答不出來為樂則是前者。我讀這一科的經驗﹐相信對下學期我開始兼讀哲學文憑課程會有幫助。至少我知道﹐要合格不難但以高份很難﹐最緊要是我知道自己會喜歡讀哲學。

The problem of induction arrived from Hume’s position as an empirical philosopher. Hume believes the source of human knowledge is experience from outside world instead of from reason within our mind. He uses Hume’s fork to divide all human knowledge into two groups, either “relations of ideas” or “matter of facts”. The “relations of ideas” is a prior proposition that can be verified with reason alone. For example, “a circle has no angle” and “pork is pig meat”. The “matter of facts” is a posterior proposition that can only be verified by experience and observations. For example, “the sun always rises from the east” and “it has 400cm of snow in Whistler”. The cause and effect of “matter of facts” are the only concerning matter in human knowledge. Every piece of information in the “matter of facts” has a cause. We know it is going to rain from the dark clouds in the sky. We know that we can take sky train and bus from downtown Vancouver to SFU from the transmit map. Therefore human does not have intelligent without understand the causality between difference pieces of knowledge.

Hume points out the causal connection between two events are discovered by experience but not by reason. Thought induction, we can establish the connection between two events. Induction is generalization work by inferring a claim about an entire population of objects from data about a sample of those objects. We have observed many people die from eating cyanide, so that we can conclude cyanide kills people. However Hume claims that we didn’t actually observe the casual connection between the two events. We only observe a sequence of two events happens one after another all the time and come to the conclusion that there is a causal relationship between them. If we in fact we cannot assert the one event will always leads to another, how can claim we have know anything at all. For example, for many years all birds observed by men have wings. We took it for granted that birds must have wings, until we discover the wingless kiwi bird in New Zealand. Therefore no matter how many winged birds we have observed, we cannot guarantee all birds have wings. The same principle can apply to any other knowledge we have. How can we prove that we will have a full moon next month? We merely expect future events will follow the past experience. We are just assuming the external world is uniform and consistence over time so that all natural phenomena are expected to repeat themselves. This is circular reasoning that we beg the question by assuming the answer we are looking for. Since all our knowledge is based on this assumption that we cannot rationally justify, Hume has shown that we in fact don’t know anything.

Karl Popper is probably the most notable philosopher in the 20th century. His philosophy works changed how the field of epistemology perceives knowledge. For the past two hundred years, the laws of physics discovered by Newton have shaped how philosophers viewed science and knowledge. Science facts are the most reliable form of knowledge in human society. Once a scientific fact is discovered and verified by rigorous experiments, it is thought that the science theory or law will not change. Many great philosophers in the modern age believe that the scope of human knowledge will expand over the time as we discover more scientific facts and add to the existing pool of knowledge. However at the turn of the 20th century, the discovery of a genius scientist Albert Einstein has shaken the foundation of the Newtonian world of physics. His famously relativity theory is compatibility with Newton’s theory. Einstein’s theory is confirmed by the eclipse observations to show that light from distant stars can be bended by the sun’s gravitational field. The consequence of this discovery to philosophy makes us reconsider our understanding of knowledge. We can no longer guarantee the certainty of what we know as any piece of knowledge can call in to question and later shown that it is wrong after all.

Popper’s philosophy shines new lights on the view of science by replacing the traditional static view of science with a more dynamic approach. First he begins with identifying the difference between science and pseudo-science, and defines the properties of a proper scientific theory. Human develop theories to explain the cause and effect between difference events from our experience and attempted to predict the expected result of similar events. Popper thinks that what makes a theory science is not whether the theory is verified to be true nor it is good. A scientific theory has to be falsifiable, namely stated the hypothetical condition that this theory is no longer valid. For example, creationism is not a scientific theory because there is no observation or test could falsify the claim that God created the world in literally 7 days, provided that God can fake any evidences showing the Earth is several million years old . On the other hand, the theory of evolution is science because we can prove it wrong if one day God or some aliens shows up and tell us they had indeed created the Earth. However, Popper didn’t go as extreme as Hume claiming all metaphysics or pseudo science theories meaningless.

Popper has changed the concept of knowledge in philosophy by realizing that there is no certainty in science. Instead he said “science is perhaps the only human activity in which errors are systemically criticized and in time corrected”. Science not only adds new knowledge to the domain, it also replaces existing theories with better ones. It is impossible to prove a scientific theory is ultimately true, we can only claimed that the theory has a tentative status quo, until new there are challenges. When new challenges arise, the old theory either have to be revised to cope with the new findings or limited its scope of assertion to remain useful. The progress of science comes from trial and errors, the continuous regression of hypothesis and observation. Every theory in science not secure, they are open for revision or rejection. All scientific knowledge could probably be false, yet it aspires eventually to the truth. Newton’s theory classical physics is still valid over in the everyday life. Its prediction breaks down when comes to the world of very large scale where Einstein’s relativity theory supplement and correct Newton’s theory. Then along come the quantum theory that is incompatible with both Newton’s and Einstein’s theory on very small scale. The three contradicting theories cannot all be right at the same time. In fact, it is very likely that all of them are wrong. However each theory is served as a stepping stone for a more accurate theory to describe our external world. Although Hume showed that it is not possible to infer a theory from induction of observations, but this does not affect the possibility or falsifying a theory from new observations. Therefore, Popper has solved by problem of induction by changing our concept of knowledge to a more practical and realistic view. Instead of knowing more about knowledge with absolute certainty, we are getting closer to the true nature of knowledge by reducing the degree of uncertainty.

Descartes starts his inquiry about the true nature of knowledge by systematically questioning all his prior beliefs. First, he concludes that knowledge deriving from senses is not reliable. Human senses are prone to error from direct and immediate observations. A different answer often surfaces when the object in question is examined in further details. Second, he argues that we are not able to distinguish the real world from dreams. Descartes does not satisfy even if he has a clear understanding of the world through senses. He questions the existence of the world that he senses. Therefore, we cannot rely on any knowledge based on the observation of the external world. After all his briefs are filtered by these two powerful doubts, only abstract knowledge, namely mathematics, exists in his mind that remains trustworthy. At this point, Descartes takes another step and introduces an additional twist to his arguments. He claims that an evil demon may exist that aims to deceive him continuously. As a result, he cannot even rely on the truths coming from reasons, as well from experience. In this thought experiment, Descartes successfully falsify almost all his perceptions, except the Cogito.

Descartes asserts that although he no longer knows what is absolutely true, he cannot falsify what he seems to perceive. He knows that he is a “thinking thing” through the fact that he is thinking, doubting, understanding, affirming, denying, willing, refusing, perceiving senses and having mental images. This fact is the light at the end of the tunnel in his quest of knowledge. He cannot deny his own existence even with the three stages of doubts: senses, dreams and evil demon. He argues that he knows with absolute certitude that he has conscious experiences and thus he exists. Descartes used the phrase “I am, I exist” to conclude the proposition of his thought experiment. Ironically, even though this phase is more precise, it is not as remarkable as the phrase “I think, therefore I am” used in his earlier work. Thus his train of thoughts is often known to later generations in the form of “Cogito ergo sum”, which gives the Cogito its name.

It is important to point out that the Cogito can only be understood from the first-person perspective. We cannot consider the preposition of “Descartes is thinking, there he exists” is valid. Each of us should follow Descartes’ foot steps individually and formulate the arguments outlined in the Meditations I and II to convince ourselves that we really know that we exist. Once the proposition of “I exist” is understood, it can be served as the foundation for the rest of our knowledge.