在傳統認知論中，知識等於真實的信念加上合理相信的理由。在尋找合理的理由時，我們采用歸納法，從已經被肯定的知識中，推論相信新知識的合理理由。可是這裹有一個問題，若每一項知識也是從先前的知識推論出來，那層層遞進地推論追溯上去，那最初的知識如何肯定呢。傳統上基礎主義認為在知識的最底層，是一些不需論證自我肯定的基礎知識，作為所有知識推論的基礎。調和主羲則否定有基礎知識的存在，所有知論的推論是個巨大的循環，只能檢視整個知識系統的一至性，有沒有內部矛盾或對世界觀測的不協調。這篇功課討論調和主義理論本身的問題，探討調和主義能否成立。

The Coherence Theory of Empirical Knowledge

In this essay, I am evaluating Bonjour’s coherence theory of empirical knowledge (CTEK) against foundational theory of empirical knowledge (FTEK). First, I will outline what is the regress problem and compare the responses from FTEK and CTEK. Then I will examine the objection against CTEK regarding its relationship with external world. I will further extend the objection by arguing CTEK is asserting a fundamental assumption that the external world itself has to be coherent for CTEK to be justified. At last I am going to conclude CTEK is unsuccessful in overcome the objection in strictly epistemological sense but it is successful in practical sense.

Since Plato, traditional view of knowledge is justified true belief. A piece of belief is only qualified as knowledge if it is justified. A belief is justified based on the validity and soundness of its argument, which is implicitly depends on the premises used in the argument are also justified. Each premise on its own is also a piece of belief which required the justification of the premise’s premises. As a result, we have a regression of justifications for premises that keep tracing back, which is known as “the regression problem”. FTEK deals with the regression problem by stating there are some foundation beliefs at the very bottom of chains of premises and the regression terminates when the basic beliefs are reached. There are two version of FTEK. The strong version stated that the basic beliefs are self-justified without the need of further premises. The weak version stated that the basic beliefs are initially credible that are likely to be true. The CTEK rejects the notation of basic beliefs, instead of having the regression of premises go on infinite linearly, the inference is circular. An epistemic system is justified by its internal coherence.

However, the circular nature of CTEK runs into the problem of begging the question, which a belief cannot be justified unless it is already justified. The solution is to reject the linear conception of inferential justification and uses a holistic or systematic conception of inferential justification instead. CTEK separate the justification into two categories, justification of a particular belief and the global justification of the entire cognitive system. The justification of a particular belief appears linear, since the premises regression will soon reached some acceptable beliefs in the context. If no acceptable belief is reached, the premises regression will continue moving in a circle. In this case, the justification of the overall knowledge system comes under questions. In CTEK, the justification of the entire system is based on its degree of coherence. A coherent system must be internally consistence, which means there is no internal conflict, but it has more than just consistency. Coherent is the systemic connection between the components of the system, how observable facts can be explained and predicted. The justified knowledge system is the one with the highest degree of coherences out of all the alternative consistence systems.

In the paper, Bonjour lists three objections to CTEK on questioning the fundamental questions of the connection between coherence and justification. Out of the three objections, Bonjour spends most of the paper in defending against objection number two, the relationship of CTEK and external world. I think this is the strongest objection against CTEK and I also think Bonjour successfully defends CTEK against this objection. However, Bonjour omitted an underlining assumption in his defence that the external world has to be coherent in order to justify his argument. In the following paragraphs, I will first out the objection, go over Bonjour’s response to the objection and illustrate his hidden assumption with a counter example.

The strongest objection to CTEK is that since CTEK is justified only in terms the internal coherence of the beliefs in the system, it does not have any relationship with the external world. A self-enclosed system of beliefs cannot constitute empirical knowledge. Bonjour’s defense is pretty straight forward, it simply link the coherent belief system in CTEK to observable facts from external world. He argues that in CTEK, the coherent system of beliefs must also coherent with reliable observation of the external world in long run. When a particular observation does not coherent with the belief system, CTEK can either neglect the particular observation as an incoherent exception to the belief system or refine the belief system to include the new observation. If there are too many incoherent exception observations accumulated in the belief system, the belief system will become less coherent with the world and eventually it will be replaced by a more coherent belief system. The belief system is continuously updating itself upon new observation to maintain its degree of coherence. The input from external world has causal relationship with the CTEK belief system where the belief system is justified by its coherence with observable facts of the external world. One of the key pieces in Bonjour’s argument is to establish what can be constituted as reliable observations yet at the same time is not a basic belief. He argues that spontaneous introspective beliefs on spontaneous sensa beliefs are very likely to be true. The reliability of cognitively spontaneous beliefs is part of the coherence system along with the observation of the external world. Therefore it is not a prior truth in the sense that it is required as the foundation for justification of the knowledge.

Bonjour based CTEK’s justification on the coherence of the belief system and the reliable observation of external world in long run. Let’s granted that the belief system and the observations are reliable, however Bonjour failed to address the underlining assumption that the external world is coherence in long run. If the external world is not coherence, then no belief system can stay coherent due to CTEK has a causal relationship with the external world. Bonjour uses the spontaneous visual belief a red book and the lack of spontaneous visual of a blue book to illustrate how the belief system is linked to the external world. What if there is a chance that the book randomly change colour every time I observe it? How can I conclude there is a red book on my desk but not a blue book on my desk? Even though I can trust my spontaneous beliefs from my sensa of the book, I cannot trust the object under my observation stays the same between my two observations. It is possible that the cover of the book is made of the latest colour changing e-paper technology, which in the case we can provide a coherent account for the observable fact. However, it is also possible that there is no scientific theory can possible explain why the book change its color. It could be the act of God and it is simply a miracle that the book changed from red to blue for no apparent reason. The CTEK justification adopt an objective clock work world view that rule out the existence of any supernatural power, such as an omnipotent God who defies all laws of physics.
In theory, we cannot epistemological justify the CTEK because we cannot epistemological justify the world is coherent. Hume argues that “Uniformity of Nature”, which is essentially the same as coherence of the world, cannot be justified, yet it is rational and non-optional for us to accept the habit of inductive inference. Practically, we can assume the world is coherent almost all of the time and take it as a weak foundation that it is probably initially true until shown otherwise. CTEK is actually a very weak FTEK in disguise; the base belief of CTEK is that the world is coherence to provide the foundation to build coherent belief systems.

However, it would be totally absurd to argue the world is not coherent. If the world is not coherent, then even FTEK is not possible to have any knowledge system. Just like FTEK cannot convince the ultimate skeptic, CTEK also fail to convince the ultimate skeptic that there is justification on any knowledge. Given the fact that assumption of the world is coherent must dialectically acceptable in the context of any knowledge theory to have any meaning, we can grant this assumption a priori status outside of any epistemic dialog. With this particular exception, I conclude that CTEK is successful in overcoming the objection regarding the relationship of coherent belief system and the external world.

Reference:
[1] Laurence Bonjour, The Coherence Theory of Empirical Knowledge, Philosophical Studies 30 (1976) p281-312

苖卡兒(Descartes)說﹕我思故我在。雖然我們可以肯定自己的存在﹐但如何可以證明在我們思想以外的世界也是存在呢﹖如何去證明人生不是一場夢﹐不是只有獨自一個人的意識漂浮在虛無之中。這篇哲學功課的題目﹐大慨正好對號入座哲學給一般人的印象﹐怎麼哲學問這個無聊的問題。其實這個問題只是大問題的其中一環﹐問世界存在的本質是什麼。這篇功課對比了Moore和Russell兩位哲學家的論證﹐前者從康德(Kant)以理論為起點﹐推論出在人與人的意識以外﹐必然存在一個外在的世界。後者則把問題反過來﹐質疑為什麼不接受世界存在﹐畢竟認為世界不存在的人精神有問題。最搞笑是話說某次Russell講學﹐其中有一個聽眾相信世界不存在﹐那當然除他以外的其他人也不會存在。可是他聽得半桶以為Russell在認同他的觀點﹐演講完畢走上台對Russell說﹐他很高興聽到有人認同他認為其他人不存在的觀點﹐一個多麼的自相多盾的說法。我證明世界存在的論証很簡單﹐如果世界不存在的話﹐我就不需要寫這篇文章交功課﹐教授也不需要花時間去改功課。既然我寫了這篇文章出來﹐教授又要花間去改﹐那就證明了世界是存在的了。

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