Daniel C. Dennett

Intentional systems in cognitive ethology: The “Panglossian paradigm” defended

Ethologists and others studying animal behavior in a “cognitive” spirit are in need of a descriptive language and method that are neither anachronistically bound by behaviorist scruples nor prematurely committed to particular “information-processing models.” Just such an interim descriptive method can be found in intentional system theory . The use of intentional system theory is illustrated with the case of the apparently communicative behavior of vervet monkeys. A way of using the theory to generate data - including usable, testable “anecdotal” data - is sketched. The underlying assumptions of this approach can be seen to ally it directly with “adaptationist” theorizing in evolutionary biology, which has recently come under attack from Stephen Gould and Richard Lewontin, who castigate it as the “Panglossian paradigm.” Their arguments, which are strongly analogous to B. F, Skinners arguments against “mentalism,” point to certain pitfalls that attend the careless exercise of such “Panglossian” thinking (and rival varieties of thinking as well), but do not constitute a fundamental objection to either adaptationist theorizing or its cousin, intentional system theory.

Time and the observer: The where and when of consciousness in the brain

We compare the way two models of consciousness treat subjective timing. According to the standard “Cartesian Theater” model, there is a place in the brain where “it all comes together,” and the discriminations in all modalities are somehow put into registration and “presented” for subjective judgment. The timing of the events in this theater determines subjective order. According to the alternative “Multiple Drafts” model, discriminations are distributed in both space and time in the brain. These events do have temporal properties, but those properties do not determine subjective order because there is no single, definitive “stream of consciousness,” only a parallel stream of conflicting and continuously revised contents. Four puzzling phenomena that resist explanation by the Cartesian model are analyzed: (1) a gradual apparent motion phenomenon involving abrupt color change (Kolers & von Grunau 1976), (2) an illusion of an evenly spaced series of “hops” produced by two or more widely spaced series of taps delivered to the skin (Geldard & Sherricks “cutaneous rabbit” [1972]), (3) backwards referral in time, and (4) subjective delay of consciousness of intention (both reported in this journal by LIbet 1985a; 1987; 1989a). The unexamined assumptions that have always made the Cartesian Theater so attractive are exposed and dismantled. The Multiple Drafts model provides a better account of the puzzling phenomena, avoiding the scientific and metaphysical extravagances of the Cartesian Theater: The temporal order of subjective events is a product of the brains interpretational processes, not a direct reflection of events making up those processes.

The Self as a Center of Narrative Gravity

What is a self? I will try to answer this question by developing an analogy with something much simpler, something which is nowhere near as puzzling as a self, but has some properties in common with selves. What I have in mind is the center of gravity of an object. This is a well-behaved concept in Newtonian physics. But a center of gravity is not an atom or a subatomic particle or any other physical item in the world. It has no mass; it has no color; it has no physical properties at all, except for spatio-temporal location. It is a fine example of what Hans Reichenbach would call an abstractum. It is a purely abstract object. It is, if you like , a theorists fiction. It is not one of the real things in the universe in addition to the atoms. But it is a fiction that has nicely defined, well delineated and well behaved role within physics.

Are we explaining consciousness yet

Theorists are converging from quite different quarters on a version of the global neuronal workspace model of consciousness, but there are residual confusions to be dissolved. In particular, theorists must resist the temptation to see global accessibility as the cause of consciousness (as if consciousness were some other, further condition); rather, it is consciousness. A useful metaphor for keeping this elusive idea in focus is that consciousness is rather like fame in the brain. It is not a privileged medium of representation, or an added property some states have; it is the very mutual accessibility that gives some informational states the powers that come with a subjects consciousness of that information. Like fame, consciousness is not a momentary condition, or a purely dispositional state, but rather a matter of actual influence over time. Theorists who take on the task of accounting for the aftermath that is critical for consciousness often appear to be leaving out the Subject of consciousness, when in fact they are providing an analysis of the Subject, a necessary component in any serious theory of consciousness.

Conditions of personhood

I am a person, and so are you. That much is beyond doubt. I am a human being, and probably you are too. If you take offense at the “probably” you stand accused of a sort of racism, for what is important about us is not that we are of the same biological species, but that we are both persons, and I have not cast doubt on that. One’s dignity does not depend on one’s parentage even to the extent of having been born of women or born at all. We normally ignore this and treat humanity as the deciding mark of personhood, no doubt because the terms are locally coextensive or almost coextensive. At this time and place human beings are the only persons we recognize, and we recognize almost all human beings as persons, but on the one hand we can easily contemplate the existence of biologically very different persons—inhabiting other planets, perhaps—and on the other hand we recognize conditions that exempt human beings from personhood, or at least some very important elements of personhood. For instance, infant human beings, mentally defective human beings, and human beings declared insane by licensed psychiatrists are denied personhood, or at any rate crucial elements of personhood.

The Mind's I: Fantasies and Reflections on Self and Soul

With contributions from Jorge Luis Borges, Richard Dawkins, John Searle, and Robert Nozick, The Minds I explores the meaning of self and consciousness through the perspectives of literature, artificial intelligence, psychology, and other disciplines. In selections that range from fiction to scientific speculations about thinking machines, artificial intelligence, and the nature of the brain, Hofstadter and Dennett present a variety of conflicting visions of the self and the soul as explored through the writings of some of the twentieth centurys most renowned thinkers.

Précis of The Intentional Stance

The intentional stance is the strategy of prediction and explanation that attributes beliefs, desires, and other “intentional” states to systems – living and nonliving – and predicts future behavior from what it would be rational for an agent to do, given those beliefs and desires. Any system whose performance can be thus predicted and explained is an intentional system , whatever its innards. The strategy of treating parts of the world as intentional systems is the foundation of “folk psychology,” but is also exploited (and is virtually unavoidable) in artificial intelligence and cognitive science more generally, as well as in evolutionary theory. An analysis of the role of the intentional stance and its presuppositions supports a naturalistic theory of mental states and events, their content or intentionality , and the relation between “mentalistic” levels of explanation and neurophysiological or mechanistic levels of explanation. As such, the analysis of the intentional stance grounds a theory of the mind and its relation to the body.

Current Issues in the Philosophy of Mind

The philosophy of mind is one of the most active fields in philosophy today, and it has changed so drastically in the last twenty years, that many of the traditionally central topics and theories have been transformed almost beyond recognition, and new concerns now loom that have no clear ancestors in the old tradition. An assessment of current work requires an understanding of recently evolved assumptions about the burdens and goals of the field, which can best be provided by a brief history of the shifts of outlook in recent years.1

The Practical Requirements for Making a Conscious Robot [and Discussion]

Arguments about whether a robot could ever be conscious have been conducted up to now in the factually impoverished arena of what is ‘possible in principle’. A team at MIT, of which I am a part, is now embarking on a longterm project to design and build a humanoid robot, Cog, whose cognitive talents will include speech, eye-coordinated manipulation of objects, and a host of self-protective, self-regulatory and self-exploring activities. The aim of the project is not to make a conscious robot, but to make a robot that can interact with human beings in a robust and versatile manner in real time, take care of itself, and tell its designers things about itself that would otherwise be extremely difficult if not impossible to determine by examination. Many of the details of Cog’s ‘neural’ organization will parallel what is known (or presumed known) about their counterparts in the human brain, but the intended realism of Cog as a model is relatively coarse-grained, varying opportunistically as a function of what we think we know, what we think we can build, and what we think doesn’t matter. Much of what we think will of course prove to be mistaken; that is one advantage of real experiments over thought experiments.

Cognitive science as reverse engineering several meanings of “Top-down” and “Bottom-up”

Publisher Summary This chapter discusses some different meanings and comment on the relations between “top-down” and “bottom-up,” and their implications for cognitive science. The terms are used to characterize both research methodologies on one hand and models on the other. The chapter describes the issues surrounding top-down versus bottom-up methodologies. The top-down versus bottom-up polarity in models of a particular cognitive capacity, language comprehension are considered. When a person perceives speech, processes occur in the brain that must be partly determined bottom-up, by the input and partly determined top-down, by effects from on high, such as interpretive dispositions in the perceiver because of the perceivers particular knowledge and interests. Alexanders comprehension machinery was apparently set with too strong a top-down component. The trade-off between top-down and bottom-up is a design parameter of a model that might be tuned to fit the circumstances. “Top-down” refers to a contribution from “on high” from the central, topmost information stores—to what is coming “up” from the transducers or sense organs.