2012年6月1日金曜日

【メモ】 Thomas Nagel, The View From Nowhere

【汎心論】

We cannot at present understand how a mental event could be composed of myriad smaller proto-mental events on the model of our understanding of how a muscle movement is composed of myriad physico-chemical events at the molecular level. We lack the concept of a mental part-whole relation. The mental may be divisible in time, but we can't in the ordinary sense think of it as divisible in space. Yet if mental events occur in a physically complex, spatially extended organism, they must have parts that in some way correspond to the parts of the organism in which they occur, and to the organic processes on which the different aspects of mental life depend. There must be a mental analogue of spatial volume and spatial complexity. (The View From Nowhere, p.50)

the unity of consciousness, even if it is not complete, poses a problem for the theory that mental states are states of something as complex as a brain. Panpsychism is just a particularly startling manifestation of this problem.  (ibid)

Though what goes on in each half of the intact brain is presumably different from what goes on in the halves when separated, it still must be something quasi-mental. And it must be something which, when added to what goes on in the other half, constitutes a whole mental life! But what on earth can this be? (ibid)

【〈今〉〈私〉の指標詞】

indexicals in general are untranslatable into objective terms, because they are used to refer to persons, things, places, and times from a particular position within the world, without depending on the user's objective knowledge of that position. (p.59)

The truth-conditions of tensed statements can be given in tenseless terms, but that does not remove the sense that a tenseless description of the history of the world (including the description of people's tensed statements and their truth values) is fundamentally incomplete, because it cannot tell us which time is the present. Similarly, the fact that it is possible to give impersonal truth-conditions for first-person statements does not enable one to make those statements without using the first person. The crucial question is whether the elimination of this particular first-person thought in favor of its impersonal truth-conditions leaves a significant gap in our conception of the world. I think it does. (ibid)

【客観性と懐疑主義】

Objectivity and skepticism are closely related: both develop from the idea that there is a real world in which we are contained, and that appearances result from our interaction with the rest of it. We cannot accept those appearances uncritically, but must try to understand what our own constitution contributes to them. To do this we try to develop an idea of the world with ourselves in it, an account of both ourselves and the world that includes an explanation of why it initially appears to us as it does. But this idea, since it is we who develop it, is likewise the product of interaction between us and the world, though the interaction is more complicated and more self-conscious than the original one. If the initial appearances cannot be relied upon because they depend on our constitution in ways that we do not fully understand, this more complex idea should be open to the same doubts, for whatever we use to understand certain interactions between ourselves and the world is not itself the object of that understanding. However often we may try to step outside of ourselves, something will have to stay behind the lens, something in us will determine the resulting picture, and this will give grounds for doubt that we are really getting any closer to reality. (pp.67-68)

The question is how limited beings like ourselves can alter their conception of the world so that it is no longer just the view from where they are but in a sense a view from nowhere, which includes and comprehends the fact that the world contains beings which possess it, explains why the world appears to them as it does prior to the formation of that conception, and explains how they can arrive at the conception itself. (p.70)

In discussing the nature of the process and its pitfalls, I want both to defend the possibility of objective ascent and to understand its limits. We should keep in mind how incredible it is that such a thing is possible at all. We are encouraged these days to think of ourselves as contingent organisms arbitrarily thrown up by evolution. There is no reason in advance to expect a finite creature like that to be able to do more than accumulate information at the perceptual and conceptual level it occupies by nature. But apparently that is not how things are. Not only can we form the pure idea of a world that contains us and of which our impressions are a part, but we can give this idea a content which takes us very far from our original impressions. (ibid)

The two [skepticism and objective knowledge] are intimately bound together. The search for objective knowledge, because of its commitment to a realistic picture, is inescapably subject to skepticism and cannot refute it but must proceed under its shadow. Skepticism, in turn, is a problem only because of the realist claims of objectivity. (p.71)

we can conceive of the possibility that the world is different from how we believe it to be in ways that we cannot imagine, that our thoughts and impressions are produced in ways that we cannot conceive, and that there is no way of moving from where we are to beliefs about the world that are substantially correct. This is the most abstract form of skeptical possibility, and it remains an option on a realist view no matter what other hypotheses we may construct and embrace. (ibid)

【自己超越】

To provide an alternative to the imaginable and unimaginable skeptical possibilities, a self-transcendent conception should ideally explain the following four things: (1) what the world is like; (2) what we are like; (3) why the world appears to beings like us in certain respects as it is and in certain respects as it isn't; (4) how beings like us can arrive at such a conception. In practice, the last condition is rarely met. (p.74)

The vast majority of additions to what we know do not require any advance in objectivity: they merely add further information at a level that already exists. (...) An advance in objectivity requires that already existing forms of understanding should themselves become the object of a new form of understanding, which also takes in the objects of the original forms. This is true of any objective step, even if it does not reach the more ambitious goal of explaining itself. All advances in objectivity subsume our former understanding under a new account of our mental relation to the world. (p.75)

Only objectivity can give meaning to the idea of intellectual progress. We can see this by considering any well-established objective advance (...) and asking whether it could be reversed. (p.77)


【進化論的認識論】

The Darwinian theory of natural selection, assuming the truth of its historical claims about how organisms develop, is a very partial explanation of why we are as we are. It explains the selection among those organic possibilities that have been generated, but it does not explain the possibilities themselves. It is a diachronic theory which tries to account for the particular path evolution will take through a set of possibilities under given conditions. It may explain why creatures with vision or reason will survive, but it does not explain how vision or reasoning are possible. (p.78)

【合理主義】

Each of us is a microcosm, and in detaching progressively from our point of view and forming a succession of higher views of ourselves in the world, we are occupying a territory that already exists: taking possession of a latent objective realm, so to speak. (p.83)

The capacity to imagine new forms of hidden order, and to understand new conceptions created by others, seems to be innate. just as matter can be arranged to embody a conscious, thinking organism, so some of these organisms can rearrange themselves to embody more and more thorough and objective mental representations of the world that contains them, and this possibility too must exist in advance. Although the procedures of thought by which we progress are not self-guaranteeing, they make sense only if we have a natural capacity for achieving harmony with the world far beyond the range of our particular experiences and surroundings. When we use our minds to think about reality, we are not, I assume, performing an impossible leap from inside ourselves to the world outside. We are developing a relation to the world that is implicit in our mental and physical makeup, and we can do this only if there are facts we do not know which account for the possibility. Our position is problematic so long as we have not even a candidate for such an account. (p.84)

Perhaps (...) Descartes' God is a personification of the fit between ourselves and the world for which we have no explanation but which is necessary for thought to yield knowledge. (p.85)

【実在論と観念論】

Suppose that, in the world in which we do not exist, one of them, call him Realist junior, develops philosophical leanings (why not?) and wonders whether there may be things about the world that he and others like him are incapable of ever finding out about or understanding. Is this impossible? That is, if he were to utter these words (supposing in other respects his language were like part of ours), would it be a mistake to take them as expressing a hypothesis which would in fact be true in that situation? Would he simply be talking nonsense without realizing it? Would he be incapable of thinking in general terms what we know to be true about his situation (what we have stipulated to be true)? Here the analogy goes in the other direction. If we would be talking nonsense by engaging in such speculation, so would he. (p.96)

【観念論における形式と内容の混同】

But what reason could there be to hold that, granting the intelligibility of the notion of things in themselves, they couldn't be spatially extended? There is no good reason-only a bad Berkeleyan reason: the move from subjectivity of form to subjectivity of content. In other words, it would have to be claimed that because we have the conception of primary qualities, detect them through observation, and use them in explanations, they are essentially relative to our point of view, though in a more complex way than secondary qualities are: relative not just to our perceptual point of view, but to our entire cognitive point of view. I believe there is no defense of this position which does not beg the question. (p.103)

【温度計と言語の比喩】

As Wittgenstein points out (Wittgenstein (2), secs. 241-2), there is a parallel between conditions of meaning and conditions of measurement. We cannot measure temperature with a thermometer unless there is a certain constancy in the results of such measurement. But that doesn't mean that temperature is nothing but a phenomenon of agreement among thermometer readings. It would exist even if there were no thermometers, and we can explain the actual agreement among thermometers by the uniform effect on them of temperature. In giving this explanation we use the concept of temperature, and a condition of our having the concept of temperature we have is that we can measure it. But that doesn't make the explanation circular, any more than a lecture on the operation of the larynx is circular. To use something that one is trying to explain is not to explain it in terms of itself. (p.109)