D. Chalmers

The project that Dan Lloyd has undertaken is admirable and audacious. He has tried to boil down the substrate of information-processing that underlies conscious experience to some very simple elements, in order to gain a better understanding of the phenomenon. Some people will suspect that by considering a model as simple as a connectionist network, Dan has thrown away everything that is interesting about consciousness. Perhaps there is something to that complaint, but I will take a different tack. It seems to me that if we apply his own reasoning, we can see that Dan has not taken things far _enough_. When we have boiled things down to a system as simple as a connectionist network, it seems faint-hearted to stop there, and perhaps a little arbitrary as well. So I will take things further, and ask what seems to be the really interesting question in the vicinity: what is it like to be a thermostat?

1. I think that by emphasizing theoretical spaces of representations, Andy has put his finger on an issue that is key to connectionism's success, and whose investigation will be a key determinant of the field's further progress. I also think that if we look at representational spaces in the right way, we can see that they are deeply related to classical phenomenon of systematicity in representation. I want to argue that the key to understanding representational spaces, and in particular their ability to capture the deep organization underlying various problems, lies in the idea of what I will call.

At the April 2006 meeting of the Central Division of the American Philosophical Association, in an author-meets-critics session on Scott Soames' book _Reference and Description: The Case Against Two-Dimensionalism_ , I presented a comment on Soames' book, "Scott Soames' Two-Dimensionalism" . The other critic was Robert Stalnaker. Soames presented his response to critics . Below is a reply to Soames' response to me, for those who were at the session and interested others. Note that this response was mostly written before the session, except for one or two paragraphs where the discussion in the session is mentioned

Scott Soames’ Reference and Description contains arguments against a number of different versions of two-dimensional semantics. After early chapters on descriptivism and on Kripke’s anti-descriptivist arguments, a chapter each is devoted to the roots of twodimensionalism in “slips, errors, or misleading suggestions” by Kripke and Kaplan, and to the two-dimensional approaches developed by Stalnaker (1978) and by Davies and Humberstone (1981). The bulk of the book (about 200 pages) is devoted to “ambitious twodimensionalism”, attributed to Frank Jackson, David Lewis, and me. After a quick overview of two-dimensional approaches, I will focus on Soames’ discussion of ambitious twodimensionalism. I will then turn to a system advocated by Soames that is itself strikingly reminiscent of a two-dimensional approach. Two-dimensional semantic theories are varieties of possible-worlds semantics on which linguistic items can be evaluated relative to possibilities in two different ways, yielding two sorts of intensional semantic values, which can be seen as two “dimensions” of meaning. The second dimension is the familiar sort of Kripkean evaluation in metaphysically possible worlds, so that necessarily coextensive terms (such as ‘Hesperus’ and ‘Phosphorus’ or ‘water’ and ‘H2O’) always have the same semantic value. The first dimension behaves differently, so that there are typically at least some cases where necessarily coextensive terms have different semantic values on the first dimension. For this reason, the two-dimensional framework is sometimes seen as a way of granting many of the insights of a Kripkean approach to meaning (on the second dimension), while retaining elements of a Fregean approach to meaning (on the first dimension)

In this paper I use thought-experiments to argue that functional organization fully determines conscious experience. These thought-experiments involve the gradual replacement of neurons by silicon chips, and similar scenarios. I argue that if "absent qualia" or "inverted qualia", are possible, then phenomena I call "fading qualia" and "dancing qualia" will be possible; but I argue that it is very implausible that fading or dancing qualia are possible. The resulting position is a sort of nonreductive functionalism

It is widely accepted that conscious experience has a physical basis. That is, the properties of experience (phenomenal properties, or qualia) systematically depend on physical properties according to some lawful relation. There are two key questions about this relation. The first concerns the strength of the laws: are they logically or metaphysically necessary, so that consciousness is nothing "over and above" the underlying physical process, or are they merely contingent laws like the law of gravity? This question about the strength of the psychophysical link is the basis for debates over physicalism and property dualism. The second question concerns the shape of the laws: precisely how do phenomenal properties depend on physical properties? What sort of physical properties enter into the laws' antecedents, for instance; consequently, what sort of physical systems can give rise to conscious experience? It is this second question that I address in this paper.

*[[I wrote this paper in January of 1990, but did not publish it because I was never entirely happy with it. My ideas on consciousness were in a state of flux, ultimately evolving into those represented in my book _The Conscious Mind_ (Oxford University Press, 1996). I now think that some parts of this paper are unsatisfactory, especially the positive theory outlined at the end, although a successor to that theory is laid out in the book. Nevertheless, I think the paper raises issues that need to be addressed. ]].

In my book _The Conscious Mind_ , I deny a number of claims that John Searle finds "obvious", and I make some claims that he finds "absurd". But if the mind/body problem has taught us anything, it is that nothing about consciousness is obvious, and that one person's obvious truth is another person's absurdity. So instead of throwing around this sort of language, it is best to examine the claims themselves and the arguments that I give for them, to see whether Searle says anything of substance that touches them

At any given time, a subject has a multiplicity of conscious experiences. A subject might simultaneously have visual experiences of a red book and a green tree, auditory experiences of birds singing, bodily sensations of a faint hunger and a sharp pain in the shoulder, the emotional experience of a certain melancholy, while having a stream of conscious thoughts about the nature of reality. These experiences are distinct from each other: a subject could experience the red book without the singing birds, and could experience the singing birds without the red book. But at the same time, the experiences seem to be tied together in a deep way. They seem to be unified, by being aspects of a single encompassing state of consciousness

This chapter describes three relatively specific forms such as destructive uploading, gradual uploading, and nondestructive uploading. Neuroscience is gradually discovering various neural correlates of consciousness, but this research program largely takes the existence of consciousness for granted. It presents an argument for the pessimistic view and an argument for the optimistic view, both of which run parallel to related arguments that can be given concerning teletransportation. Cryonic technology offers the possibility of preserving our brains in a low‐temperature state shortly after death, until such time as the technology is available to reactivate the brain or perhaps to upload the information in it. Reconstructive uploading from brain scans is closely akin to ordinary (nongradual) uploading from brain scans, with the main difference being the time delay, and perhaps the continued existence in the meantime of the original person.

The easy problems of consciousness are those that seem directly susceptible to the standard methods of cognitive science, whereby a phenomenon is explained in terms of computational or neural mechanisms. The hard problems are those that seem to resist those methods. The easy problems are easy precisely because they concern the explanation of cognitive abilities and functions. Once we have specified the neural or computational mechanism that performs the function of verbal report, for example, the bulk of our work in explaining reportability is over. Baars theory of cognitive accessibility addresses many aspects of human cognition and shows promise as a theory of awareness, the functional correlate of conscious experience, but an explanation of experience itself is not on offer. The key is the conceptual point that the explanation of functions does not suffice for the explanation of experience.

In this chapter, the author says that the standard view of brain‐in‐a‐vat scenario is endorsed by the people who created The Matrix. The author argues that the hypothesis that he is envatted is not a skeptical hypothesis, but a metaphysical hypothesis. That is, it is a hypothesis about the underlying nature of reality. According to the author, the Matrix Hypothesis is equivalent to a version of the following three‐part Metaphysical Hypothesis. First, physical processes are fundamentally computational. Second, our cognitive systems are separate from physical processes, but interact with these processes. Third, physical reality was created by beings outside physical space‐time. The Metaphysical Hypothesis combines the Creation Hypothesis, the Computational Hypothesis, and the Mind‐Body Hypothesis. It also adds a more specific claim: the computational processes underlying physical space‐time were designed by the creators as a computer simulation of a world.

This chapter provides a rich philosophical discussion of superintelligence, a widely discussed piece that has encouraged philosophers of mind to take transhumanism, mind uploading, and the singularity more seriously. It starts with the argument for a singularity: is there good reason to believe that there will be an intelligence explosion? Next, the chapter considers how to negotiate the singularity: if it is possible that there will be a singularity, how can we maximize the chances of a good outcome? Finally, it considers the place of humans in a post‐singularity world, with special attention to questions about uploading: can an uploaded human be conscious, and will uploading preserve personal identity? The chapter also analyzes whether there are certain constraints on design of artificial intelligence (AI) and AI+ that we might impose, in order to increase the chances of a good outcome.

Two-dimensional approaches to semantics, broadly understood, recognize two "dimensions" of the meaning or content of linguistic items. On these approaches, expressions and their utterances are associated with two different sorts of semantic values, which play different explanatory roles. Typically, one semantic value is associated with reference and ordinary truth-conditions, while the other is associated with the way that reference and truth-conditions depend on the external world. The second sort of semantic value is often held to play a distinctive role in analyzing matters of cognitive significance and/or context-dependence