我們的世界是一個大錯覺（Grand Illusion）嗎？

作者：許舜斌

內文：

對於一般人來說，我們每天所接觸到的世界就是最真實不過的世界，為什麼哲學家還要去懷疑這個世界呢？但如果我們接觸到的就是真實世界，那為什麼會有幻覺、錯覺呢？而從主流的認知科學的角度來看，我們認知到的世界是被腦所建構出來的，而沒有接觸到外在世界，我們認知到的都是腦中的資訊。如同電腦一般，我們可以輸入外界的資訊，如模擬颱風，但是這些資訊不是真實世界，只是內容是關於外界資訊。而傳統的懷疑論就是建立在這個基礎上，質疑我們倒底有沒有能力認識到這個世界。在普遍所接受的認知架構下，人腦負責接受外界刺激，透過腦中的演算，建立出關於外在世界的資訊。Dennett (Dennett, 1991) 提出另一種形式的懷疑論，主要針對人類信念，認為一般人認為自己擁有豐富、仔細的資訊，但是他認為這是一個大錯覺（grand illusion），因為人類擁有的資訊是破碎、不完整的。例如，當你走到一個畫滿瑪莉蓮夢露的房間，你認為你看到完整的房間資訊，每一個瑪莉蓮夢露都清楚的看到，但是如果有一張瑪莉蓮夢露劃上一些記號，你卻無法區分出來，因此你對於你認知系統的信念是錯誤的，所以你活在一個大錯覺中。而在主流的視覺研究當中，change blindness和inattentional blindness提供了一個大錯覺的支持證據。Inattentional blindness是因為注意力沒有放在目標物體上面，而導致受試者沒有注意到該物體的變化，一個經典的例子在受試者被問路的時候，一組工人搬巨大的木板移動穿越問路者與受試者兩人之間，這時候把問路者換成另外一個人，在這種情況下，受試者有百分之九十的機率不會發現改變，即使衣服、性別等巨大變化，也無法區分出來。而Change blindness主要是利用兩張圖的切換，請受試者區分兩張圖的差異 (1) ，而受試者需要花很長的時間才有辦法找到該明顯差異，但我們一般人的信念確認為我們已經看清楚整張圖，因此信念關於腦中資訊與腦中資訊是無法對應的，所以是錯誤的、是一個錯覺。這兩種懷疑論可以區分成world illusion和perceptual illusion(Kirk Ludwing, 2006)，主要是三者的關係，外在世界、腦中資訊、信念。而world illusion是外在世界與腦中資訊的關係，認為我們所知覺到的世界（由腦中資訊所提供）與真實外在世界不符合，因此我們知覺到的世界只是我們建構出來的世界，沒有反應出真實世界的結構。相對地，perceptual illusion是腦中資訊與信念之間的關係，我們關於認知系統所提供的腦中資訊的信念是錯誤的，因為一般人都認為自己擁有充分、完整關於外在世界的資訊，但是信念是錯誤的，事實上你的認知資訊是不完整、破碎的。而在Alva Noë (Noë, 2002)認為這兩種是在一個錯誤的架構在談問題，因為不管是主流學派或是Dennett都預設在一個snapshot conception的架構，認為腦中的資訊就是認知的全部，因此爭論的重點都在腦中資訊是完整的。首先，(Dennett 1991; Noë 2002; Ludwig 2006)認為我們的信念不是「我們擁有豐富、完整的資訊」，而是「我們只要改變我們的位置就能看到更多的資訊」，因此對於perceptual illusion的問題，Noë認為我的信念跟認知是符合的，沒有grand illusio的問題。進去論證他對認知理論的特殊觀點，我們的認知是建立在sensorimotor skill之上，因此動作對於認知是重要的。所以去論證傳統討論大錯覺的基礎是有問題的，我們需要建立在新知覺理論上，就能成功解決兩個問題。從上面這些討論，建立了一個重要視覺理論的討論，就是我們認知系統提供了怎麼的資訊在我們的腦中，是否我們活在一個大錯覺中呢？

1. 請參考 http://www.usd.edu/psyc301/Rensink.htmReference:Dennett, D. (1991). Consciousness Expained. Boston, Little, Brown.Ludwig, K. (2006). Is the Aim of Perception to Provide Accurate Representations? in 'Contemporary Debates in Cognitvie Science'. ed. by R. J. Stainton, Blackwell Publishing Ltd: 259-274.Noë, A. (2002). "Is the Visual World a Grand Illusion?" Journal of Consciousness Studies 9(5-6): 1-12.

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Michael 哲學論文讀後感 - “The Causal Theory of Mind – D. M. Armstrong"

Author: Michael Hsu (許舜斌)
Date: 7/18/2006

Journal:
Armstrong uses the Causal analysis of mental states to prove that the statement, mental states are physical states of the brain, is intelligible, so scientist can use his framework to explain the mind. The causal analysis explain concepts by the effect of certain cause, but to explain a mental state may be not easy for needing other mental states. For example, how we explain a purpose needs beliefs, other purposes, or perception, so mental states are explained by other mental states. In addition, different mental contents, like a desire for water and a desire for food, are distinguish by the relation between cause, effect, and other mental states, so in this sense I think the causal theory of mind is a kind of holism of mental contents. However, I always have a question about the holism of mental contents, how do we distinguish the same mental content, like a belief about god, in different people? In other words, because in causal theory we distinguish a mental content by other mental states, two identical mental contents should have the same relation among other mental contents in this sense. If a person learns a new belief, the relations among beliefs, desire, etc. are totally different. So, do we say he can’t be found any the same belief?Another debate, which had deal by Armstrong, is about the second qualities, and I think it is the debate about consciousness. Because consciousness has some special properties, like subjectivity and qualitiveness, so physicalists always want to explain away these properties. In this paper, I think Armstrong want to explain away the qualitiveness by arguing the second qualities, which are always taken as a sword against physicalism, are only physical properties in external world. He uses colors to be a example, and he thinks that colors are perceived object, which are in external world. But, in cognitive science we have a lot examples to say colors are created in our brain. For example, the same color surrounding different colors is seen as two different colors, but the same stimulus cause our retina. (sees below link, an example for this kind of illusion) In this sense we receive the same causes from external world, but we don’t have the same colors. So, how does Armstrong explain colors as external properties?

Color Illusion: http://www.grand-illusions.com/square.htm
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Michael 哲學論文讀後感 - “The Philosophy of Mind _ The nature of mental states – Hilary Putnam"

Author: Michael Hsu (許舜斌)
Date: 7/13/2006

Journal:
The problem of mind is an important issue in philosophy. After the scientific revolution, more and more people, philosophers and scientists, think that dualism is not substantial and mental states must be objective states, which are compatible with physical science. In the twentieth century, there are three important branches explaining the issue. In the first one, coming from logical positivism, they think a mental state can be analyzed in terms of behavioral patterns. The second one identifies brain states with mental states, and it is so called physicalism. The third one, which is the main topic of this paper, is functionalism, it identifies mental states with functional roles or functional states, whose idea comes from Turing Machine. Because functionalism needs to ground the functional state by behavioral patterns, it is an advanced version of behavioralism in this sense. So the debate in the philosophy of mind is turned to the debate between functionalism and physicalism, whether mental states go with physical properties or functional properties. But I think that before answering the debate we need to know what mental states or mental properties are. Consciousness is a taboo before the 1990s, so Putnam didn’t consider this one. I think losing consciousness or conscious properties is the same as losing the mind, so even if we can use objective terms, functional terms or behavioral terms, to explain mental states, we may lose this aspect.Putting aside this question, I think there is another point in the debate, which is the distinction between simulation and reality, because the main argument of this paper against physicalism is the argument from multiple realization. In other words, what are the limitations in computability? Only computable functions simulated in computers can’t be distinguished from reality; in other words, only computable functions can be realized in different physical properties. The contemporary view of computability based on Turing Machine, which is used in Putnam’ s paper, it defines what is computable. Based on Turing Machine, the computable function is limited in the domain of natural numbers. However, there are a lot of functions which are not in the domain of natural number, and a lot of functions, which describe phenomenon in physical world, are this kind of functions. This world may have a lot of important phenomenon which can’t be captured by the functions in the domain of natural number, and we can only use computers to simulate the function in the domain of natural number. So we can’t simulate the mind in this sense, we only can simulate (realize) mind in the same physical realizer. If it is reality, mind only can go with some specific physical property, which can realize this kind of function. However, whether we can extend the range of computability is another question.
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