Philosophy

Early philosophy tends not to distinguish strongly between different areas of inquiry. For the most part the earliest Greek philosophers, for example, Thales of Miletus (624-546 BCE), speculate as to the most basic elements of the world, and how these elements result in all other objects, properties, and events. Thales supposes that water is the most basic element, and all other objects, properties, and events result from changes to water. Scholars commonly identify Thales as the first philosopher in the western tradition, and Miletus, a city on the coast of present-day Turkey, as western philosophy�s point of origin. Thales reportedly predicted a solar eclipse in 585BCE, and it is Thales' combination of empirical astronomy and theoretical speculation that lead many to identify Thales as the marking the beginning of western science as well. Thales and many of the early greek philosophers were physicalists or materialists, holding that all that exists is matter and the void. However, many Greeks believed in immortal souls. With the decline of Greek and Roman civilization, religous approaches to understanding the universe eclipsed the ancient materialism of the Greeks.

Most of what we know about the early Greek philosophers comes from fragments of their writings and reports of their views in the works of later writers. However, by about 400 BC philosophers like Plato (427-347BCE) and Aristotle (400-320BCE) have begun to write works covering more or less specific areas of inquiry, and spent significant time considering investigative methodology. Both of these thinkers contributed to the two general areas of inquiry that converge (for some) upon the explanatory schema of cognitive science: Epistemology (The Sub-discipline Exploring the Nature, Sources, & Limits of Knowledge) & Philosophy of Mind (The Sub-discipline Exploring the Nature of the Mind). Additionally, the ancient Greek philosophers considered what we know as the the sciences and mathematics to be part of philosophy. Plato wrote the Meno and later the Theatetus, both of which prove to be influential works in epistemology. But, epistemological ruminations date back to the presocratics and continue today. Likewise, in The Republic, Plato introduces the tripartite division of the soul, which has strongly influenced conceptions of the mind and its operations. According to that work the soul has three parts; the appetitive soul, the spirit or passionate soul, & the thinking or rational soul. Each element of the soul has its own characteristic desires. The good for humans consists in the subjegation of the appetitive soul to the passionate soul, which is in turn subjegated to the rational soul. Thus, reason, emotion, and appetite become separate in Plato. One might argue that this represents the first attempt to understand the mind in terms of constitutive elements of the mind, the functions they perform, and the relationships that emerge. In De Anima, Aristotle considers not only human mentality, but nature of the souls of all living creatures. Aristotle's notion of a soul involves aspects of a lifeforce and of mentality. Souls are essences that combine with matter to create the specific sort of creature with specific sorts of properties and capacities. Aristotle believes that plants possess the ability to gain nourishment and reproduce themselves; animal souls have the additional capacities of sense perception and ambulation. Only human souls have the capacity for intelligence, and only the intelligent aspects of the soul are immortal for Aristotle. De Anima includes discussions on methodology, the senses, and thought and reasoning.

One of the most under appreciated figures in shaping the western notions of mathematics, philosophy, science, rationality and mentality is Euclid of Alexandria (325BCE-265BCE). Euclid is a Greek mathematician, who likely received his training in geometry in Athens from students of Plato before moving to Alexandria. Euclid's best-known work, The Elements (approximately 300BCE), systematically and rigorously organizes geometrical knowledge in terms of undoubtable axioms from which all other truths are deduced by careful proof. The Elements also includes a tresatment of basic number theory. The Elements provides readers with a comprehensive collection geometrical theorems and proofs developed by such earlier mathematicians as Thales, Pythagoras, Plato, Eudoxus, Aristotle, and Menaechmus. Euclid's accomplishment in The Elements was not its content, per se, but the organization and rigor of its presentation. Indeed, academics use Euclid's book as a text as late as the beginning of the 20th century. Euclid's rigorous axiomatization creates a model for mathematics, philosophy, and science that remains influential today, and which often serves as a model for rational thought. Euclid's geometry proves so influential that it influences great thinkers holding very different theories about the nature of the mind. For instance, Thomas Hobbes (1588�1679) is a hard-bitten physicalist. Hobbes views all things, including politics and the mind, in terms of mechanistic operations upon physical matter. Hobbes speculates in his Elements of Philosophy that �By ratiocination [reasoning], I mean computation,� (p. 7) which Hobbes' views as analogous to simple arithmatical operations upon words, where words come to signify the objects of our experiences stored memory. As we will see below, Ren� Descartes (1596�1650) models both his epistemology and his scientific method on Euclid, though he famously hold that the mind is immaterial. Baruch de Spinoza (1632�1677) writes his famous, posthumously published work Ethics in an axiomatic format. In the Ethics Spinoza argues that the universe consists of one infinite, necessary, and deterministic substance that he seems to equate with both God and nature, with both mind and body.

All these thinkers portay one�s knowledge--and rationale belief corpus--as having (or ought to have) an organizational structure and genesis like the Euclidian geometery of The Elements. One�s knowledge all flows from careful arguments based upon premises (axioms), the truth of which one cannot doubt. Deductive reasoning transmits the certainty and truth of one�s initial principles to all other beliefs.

Thus, the impact of Euclid consists in providing a paradigmatic instance of intellectual accomplishment, which can and does serve as an extremely influential conception of reason itself--and often all mentality--as consisting in deductive operations on statements tracing back to a set of statements held to be certain and undoubtable. That is, in terms of logical operations on truth-functional representations (i.e., representations that can be true or false). One cannot underestimate the impact of this conception of reason and mentality upon our theoretical musings upon rational inquiry, reason, and the mind.

Scholars generally hold that the European Renaissance began in the Italian city state of Florance in Tuscany in the 14th century. The increase in commerce, artistic, and religious activity associated with the period from the 14th to the 17th century also brought increased scientific activity that eventually lead to what historians call the scientific revolution. Writers often associate the beginning of the scientific revolution with the publication of two important works: Nicolaus Copernicus' (1474-1543) death in 1543 marks the publication (in Germany) of his privately circulated manuscript called Commentariolus (Little Commentary) under the title De revolutionibus orbium coelestium (On the Revolutions of the Heavenly Spheres, published in 1543 at Nuremberg, Germany). The physician, Andreas Vesalius (1514-1564), publishes his seven volume text on anatomy called De Humani Corporis Fabrica (On the Fabric of the Human body, published in 1555). Both of these works challenge the traditional theories and figures in their areas. Copernicus forwards the heliocentric conception the the universe in contrast to Ptolemy. Vesalius challenges many aspects of the anatomical teachings of Galen. These works and many others served to create a tradition of deterministic mechanism in science. This tradition increasingly sought to understand all phenomena in terms of universal physical laws discovered through contolled empirical experimentation, even life and the mind. The French philospher, physicist, mathematician, anatomist Rene Descartes (1596-1650) painted the tension between the spiritual or immaterial world view and the mechanistic physical world view in stark contrast in his works, particularly his highly influential work Meditations on First Philosophy (1641).

Like all thinkers of the time, Descartes is dualist as well as a scientist, mathematician, and philosopher--though those endeavors are not particularly distinct at the time. He came to science rather indirectly: Descartes attends a Jesuit school located at La Fl�che, France called Coll�ge Royal Henry-Le-Grand in 1607. His graduation from Henry-Le-Grand sees him earn his degree and license in Law at the University of Poitiers in 1616. Descartes joins the army of the Dutch Republic for a brief time in 1618, during which time he meets Isaac Beeckman, who reignites his interest in physics and mathematics. Descartes claims to have had dreams shortly thereafter which he interprets as a divine sign that he should found a unified science of nature based upon mathematics.

Descartes' work, Meditations on First Philosophy (1641), proves important for two reasons: (1) Because as a scientist and mathematician, he brings the goal rigorous scientific methodology and explanation to philosophical speculation regarding the mind. For instance, Descartes defines the properties of mental and physical substance, thereby further articulating the sorts of properties and causal connections that ought to underlie any explanation of the mental. Descartes defines two substances,one mental and one physical. However, unlike thinkers before him, Descartes attributes wholly different contradictory properties to these different substances. Descartes characterizes mental substance as a non-extended thinking substance that manifests mental properities like consciousness and belief. In contrast, physical substance is essentially extended, having properties of shape, size, positon, and number. (2) Because of his dualist conception of the mind, and because of his scientific slant on philosophy, the Meditations --as well as his Les Passions De L'ame (Passions of the Soul, published in 1649) and Traite de l'homme (Treatise on Man, published 1664, written 1637), lay the groundwork for a switch in emphasis in the philosophy of mind. Whereas philosophic speculation regarding the mind has had a strong epistemic and funstional emphasis before Descartes, emphasis turns somewhat away from epistemology and towards ontology. That is, philosophers become increasing interested in understanding if/how the mind could be physical in nature and explained through science. This interest continues today, and has led to the explicit formulation of a variety of theories regarding the nature of the mind and its relationship to the physical world. Though Descartes was a dualist, he actually furthers the mechanistic picture in that he views the body as an elaborate machine. He takes pride in his claims to have furthered mechanistic explanation of human and animal behaviors.

Ironically, it is the emphasis on science and physicalism that inspires the climatic works on the mind with a strong epistemic stance. John Locke (1632-1704) writes my An Essay Concerning Human Understanding (1690) to flush out the corpuscularian philosophy (essentially the hypothesis that the physical world is composed of atoms and �the void� which he learns from the great chemist Robert Boyle) with regard to the mind. Like all British Empiricists, Locke seeks to understand the mind in order to more accurately understand and theorize about the nature, limits, and sources of knowledge. David Hume (1711-1776), shares Locke�s project of understanding the nature of the mind in order to understand the nature, sources, and limits of knowledge. However, reflection upon observations--as opposed to a particular ontological picture--drive Hume's theorizing in works like, A Treatise of Human Nature (1739-40) and An Enquiry concerning Human Understanding (1748). I come to the conclusion that empiricist theories of mind undermine one�s claim to knowledge of physical objects and causality.We both outline theories of mind that have representations and operations on those representations. Unlike Hobbes--but like Descartes--Locke's and Hume's model for representations are pictures. Locke and Hume view the mental processes underlying thought and reasoning as resulting from operations on ideas. Of particualr significance, Hume views human reasoning about the experiences as resulting from operations of association rather than by deduction. For example, Hume thought that cause and effect reasoning results from habitual associations between ideas because of their constant conjunction in experience. In the An Abstract of a Book lately Published: Entitled A Treatise of Human Nature etc. (1740) tells readers that,

Tis evident that all reasonings concerning matter of fact are founded on the relation of cause and effect, and that we can never infer the existence of one object from another, unless they be connected together, either mediately or immediately... Here is a billiard ball lying on the table, and another ball moving toward it with rapidity. They strike; and the ball which was formerly at rest now acquires a motion. This is as perfect an instance of the relation of cause and effect as any which we know, either by sensation or reflection. (�8-9)

The third famous British Empiricist George Berkeley (1685-1753), differs from Locke and Hume in that his work emphasizes ontologial issues. Indeed, in his works, A Treatise Concerning the Principles of Human Knowledge, Part I (1710) and Three Dialogues Between Hylas and Philonous (1713), Berkeley argues against materialism in favor of a view called Idealism, in which nothing exists but minds and their ideas.

Thus, with Berkeley we see the three major classes of theories regarding the ontological nature of the mind and body. First, materialism (or reductive materialism) holds that there is only one type of substance, material substance. The mind and all mental properties result from modifications of the same substance as all other things, i.e., the mind = the body. Second, dualism (or substance dualism) holds that there are two distinct kinds of substance, mental substance and physical substance. The mind is a mental substance, while the body is a physical substance. Finally, idealism holds that there is only one kind of substance, mental substance, and all physical objects and properties are actually ideas and their properties. As well see soon, these basic positions have many permutations.

Interestingly, Thomas Reid (1710-1796) rigorously rejected the notion of a representational mind at about the same time that people were reading Hume and Locke. Another sort of objection, this time to the idea of a scientific psychology comes from Immanuel Kant (1724-1804). Kant, a physicist and philosopher, adopts the same general project of understanding the nature of the mind in order to further epistemological theorizing as Hume.. However, in his book, The Critique of Pure Reason (Kemp Smith's English translation 1929), Kant wants to counter Hume�s skeptical conclusions. Kant argues that much of our knowledge flows from the innate presuppositions necessary for experience itself. Interestingly, though Kant develops and draws heavily upon a theory of the mind in his work, he argue that a science of the mind is impossible because the field cannot be mathematicized.

Despite Kant's skepticism, scientific psychology does begin to develop. By 20th century concerns over how best to understand and explain the mind�s physical origins drives philosophical speculation regarding the mind, supplanting the emphasis on epistemology. Additionally, concerns arising from philosophical interests in language and mathematics begin to pervade the philosophy of mind. Particularly in the second half of the twentieth century, philosophers expand upon the basic theories of mind just discussed. It is, therefore, convient to use this section to outline the standard positions in the philosophy of mind, including those that developed during this period.

As noted above, each view--reductive meterialism, dualism, and idealism constitute categories of theoretical positions in which permutations exist. For instance, in the case of dualism philosophers commonly note three distinct positions: Descartes, held the most common position--interactive dualism. Interactive dualism holds that mental substance and physical substance causally interact with one another. Interactive dualism might seem like the only possibility. However, two other possibilities emerge if one denies that mental and physical substances interact. Such a denial might seem ridiculous given the apparent connection between mental phenomena and physical phenomena. For instance, if some one steps on your foot, a physical phenomena, you will likely experience a feeling of discomfort in your foot, a mental phenomena. However, Descartes' clarity and rigor in differentiating mental and physical substance, ironically, raises a significant challenge to interactionism.

Recall that mental substance is essential non-spatial, lacking all physical properties. Likewise, physical substance is essentially spatial, lacking all mental properites. If the mind and the body are fundamentally different sorts of stuff, one must ask, "How could these two substances possibly causal interact with one another?" For that matter, given that the mind is non-spatial, where could they possibly causally interact. It seems indubitable that the mind and the body interact with one another, and so interactive dualism must explain how such causal interaction could possibly occur. Philosphers have articulated many difficulties with interactive dualism, but most agree that the difficulties with causal interaction has to rank very high. In addition to difficulties with the very idea of inter-substance causation, another serious difficulty emerges almost immediately from dualistic interactionism. In a mechanistic, deterministic physical science, all changes in the physical would should (at least in principle) should be explicable by universally applicable purely mechanistic, deterministic physical laws. But, if mental substances and causal substances causally interact, mental causation renders universal purely mechanistic, deterministic physical laws impossible. Mental to physical cuasation will always fall outside purely physical laws.

One possible solution to this last worry involves denying interactionsim--at least in one direction. Epiphenomenalism is the view that changes in physical substances can causal mental phenomena, but that changes in mental substances cannot cause changes in physical substances or their properties. Thus, one can still hold that some causal connections exist between the mental and the physical, but mental causation will never violate universally applicable purely mechanistic, deterministic physical laws. While epiphenomenalism might allow for deterministic physical laws, it implies that mental phenomena never cause physical phenomena--violating the seeming obvious nature of mind-body interactions. Worse still, epiphenomenalism must explain why causation only runs from the physical to the mental, and not vice versa.

The second dualist solution to the problem of interaction also denies interactions. Parallelism is the view that mental and physical substances only appear to causally interact. Instead of causal interaction, mental and physical changes merely mirror one another, creating the illusion of interaction. One might find one anti-interactionism less plausible than the next. However, considering the difference between causation and correlation might make parralelism seem somewhat more plausible. The time on my watch may always correlate with the time on your watch, but no one supposes that our watches causally interact.

One can summarize the various substance dualistic positions in the following table:

Possible Substance Dualisms
	Mental to Physcial Causation	Physical to Mental Causation
Interactionism	YES	YES
Epiphenomenalism (mental)	NO	YES
Epiphenomenalism (physical)	YES	NO
Parallelism	NO	NO

Diagram depicting the position called substance dualism (interactionism) according to which minds and physical bodies are ontologically distinct. They are different types of substances, each of which can have distinct types of properties. Here conveniently yet inaccurately modeled by bubbles.

Substance Dualists seem to face a choice between difficult options: Epiphenomenalism and parallelism imply that the seeming robust causal interaction between mental and bodily phenomena is illusory. Interactionists, in contrast, face the daunting challenge of explaining how such different type of substances having such different properties can causally interact. Physicalism might seem to have an obvious advantage in that it does not suppose that the mental and the physical are radically different. However, this very strength presents the physicalist with a challenge. Specifically, mental properties do seem different from other sorts of physical properties. Indeed, many people find the idea that mental properties are just physical, mechanistic properties intuitively unpalitable. For instance, every physical object has mass, but only animals seem to be candidates for conscious qualitative experiences. Why, one might well ask, are only some physical objects candidates for mental properties? Similarly, mental properties seem qualitatively different from physical properties. How do mental properties arise from physical properties and processes?

The first answer to the sorts of questions was simply that mental properties were just physical properties. Such views are expressed by, for example, Aristotle when he claims that,

However, most historical accounts trace type-type indentity theory to two papers "Is Consciousness a Brain Process?" by U.T. Place (1956) and "The 'Mental' and the 'Physical'" by Herbert Feigl (1958). The first attempt to systematically address the difficulties for physicalism is a position called Logical or Analytical Behaviorism. In general, most historians cite Gilbert Ryle's book, The Concept of Mind (1949), then Hempel's "The Logical Analysis of Psychology" (1935,1949). However, Hempel's article was published, though in French, over 14 years earlier. Both works are important because they share a common shift of emphasis that has continued to shape thinking about the mind in philosophy. Both Ryle and Hempel seek to defuse the seeming difficulties in understanding how mental properties arise from physical properties by arguing that the meanings of mental terms are exhausted by behavioral terms. Hempel tell readers,

While Hempel's aim is primarily scientific and ontological, Ryle's work is neither. Instead, Ryle's work is primarily a work in the analysis of the concepts of ordinary language. In both cases, however, the seeming difficulties associated with the equation of mental properties and physical properties are traced to an improper understanding of the true meanings of mental terms. Logical behaviorism faces two significant difficulties. On the one hand, the meanings of many mental terms seem essentially tied to qualitative subjective experience as opposed to the behaviors they cause. Thus, many people find the awfulness of pain essential to being in pain, but few find verbal demonstrations essential to being in pain. On the other hand, many mental properties such as aibohphobia (the fear of palindromes) seem not to have any definitive set of behvorial effects. Thus, a person paralized by curare will not exhibit the normal behavioral effects of pain when stabbed in the arm. However, it seems impropable to suppose that such a person feels no pain. Likewise, actors really do suffer for their art according to logical behaviorists. Similarly, the causes and effect of your belief that this text is remarkably dry cannot be determined in isolation. If you love dry and boring texts, you may read all night. If you are hungry, your belief may result in your getting a chocolate bar.

As noted above, historians generally credit the british philosopher and psychologist U.T. Place (1924-2000) and the Austrian philosopher Herbert Feigl (1902-1988) as the source of the modern identity version of physicalism. Place's colleague, J.J.C. Smart (1920- ) also adopts this position. The identity theorists' motivations stem in large part from and build upon the difficulties with logical behaviorism. For instance, Place tells readers,

The view that there exists a separate class of events, mental events, which cannot be described in terms of the concepts employed by the physical sciences no longer commands the universal and unquestioning acceptance amongst philosophers and psychologists which it once did. Modern physicalism, however, unlike the materialism of the seventeenth and eighteenth centuries, is behaviouristic. Consciousness on this view is either a special type of behaviour, 'sampling' or 'running-back-and-forth' behaviour as Tolman (1932,p. 206) has it, or a disposition to behave in a certain way, an itch for example being a temporary propensity to scratch. In the case of cognitive concepts like 'knowing', 'believing', 'understanding', 'remembering' and volitional concepts like 'wanting' and 'intending', there can be little doubt, I think, that an analysis in terms of dispositions to behave (Wittgenstein, 1953; Ryle, 1949) is fundamentally sound. On the other hand, there would seem to be an intractable residue of concepts clustering around the notions of consciousness, experience, sensation and mental imagery, where some sort of inner process story is unavoidable (Place, 1954). It is possible, of course, that a satisfactory behaviouristic account of this conceptual residuum will ultimately be found. For our present purposes, however, I shall assume that this cannot be done and that statements about pains and twinges, about how things look, sound and feel, about things dreamed of or pictured in the mind's eye, are statements referring to events and processes which are in some sense private or internal to the individual of whom they are predicated. (p.44)

There are two central ideas behind type-type identity: First, Place and Feigl hold that behavioristic and identity analyses of mental terms do not exhaust the meaning of mental terms in ordinary language. That is, the new definitions of mental terms are not analytic--they do not capture the individually necessary and jointly sufficient conditions thought to dictate the meanings of ordinary terms. Place and Feigl hold that mental and physical terms pick out classes or kinds of things in virtue of their meanings, and that a significant part of the meaning of ordinary mental terms (as well as of the identity theorists new analyses of those terms) is synthetic--i.e., going beyond the definitional meaning, usually as a result of experience. Specifically, they hold that the various behavioral associations between mental terms and physical/bodily terms serve to provide an initial description of a physical (brain) state. One can modify the intial behavioral descriptions, to the entent necessary, as a result of experience. Such descriptions ultimately determine the physical state that corresponds to the mental state. The identification of the physical state with the mental state constitutes a synthetic discovery.


Herbert Feigl (1902-1988)	U.T. Place (1924-2000)	John Jamieson Carswell "Jack" Smart (1920- )

Diagram depicting Type-Type Identity Theory. Type-type theorists claim that there is only physical substance. Mental properties exist, but are type-identical to physical properties. The identity is made by using the physical behavioral associations between mental and physical terms to identify the physical state type corresponding to the mental state type.

In 1970, Donald Davidson (1917-2003) proposed an new version of identity physicalism. Davidson starts his chapter, "Mental Events," by stating his motivation for the view,

Mental events such as perceivings, rememberings, decisions, and actions resist capture in the nomological net of physical theory. .... I start from the assumption that both the causal dependence and the anomalousness of mental events are undeniable facts. My aim is therefore to explain, in the face of apparent difficulties, how this can be. (p.138)

By nomolgical Davidson simply means law-like, and by anomolousness Davidson means not falling under exceptionless universal laws. Davidson thinks that the failure to find simple type-type identifications suggested by theorists like Smart, Plcae, and Fiegl and the failure for psychology and sociology to generate universal exceptionless laws warrants a reconsideration of the type identity theory. Though Davidson tells readers in the quote above that he takes the anomalousness of the mental as an undeniable fact. However, he does offer a reason for that anomalousness--attributions of mental terms are guided primarily by providing an understanding of the person as a rational agent. This emphasis on rational understanding can, and Davidson suggests does, often trump ascriptions that would support universal and exceptionless laws. Davidson holds that the physical world has proven to be a mechanistic and deterministic by the dramatic success of sciences like physics. Davidson understands these sciences as producing exceptionless universal laws. These laws are formulated using exclusively physicalistic descriptions, and yeild a closed, complete deductive system. That is, given a complete physicalistic description of some state of the world, called an event, a scientist can, at least in principle, use the exceptionless laws of the relevant science to deduce how the causal world will unfold by deducing the resulting event, i.e., the exclusively physicalistic description of the world resulting from the prior event. Davidson felt that psychological generalizations could also be used to explain and predict by relating mental events, descriptions of some state of the world using exclusively mentalistic terms. However, mental events were not related to one another using exceptionless universal mental laws. Hence, psychological laws do not form a closed, complete deuctive system. Thus, Davidson concludes that there cannot be exceptionless universal "bridge-laws"--laws that relate mental descriptions of states of the world, mental events, to physical descriptions of states of the world, physical events. Though the argument seems complex, it's actually pretty straightforward. Physical laws are universal and exceptionless. Mental laws are neither universal nor exceptionless. But, if there were universal and exceptionless laws linking mental and physical events, then they would provide a basis for universal exceptionless mental laws. Hence, there can be no universal and exceptionless bridge laws.

Not all philosophers see the failure to discover the mental type to physical type identities and robust psychological laws predicted by type-type identity theory, as the central difficulty for theorists like Feigl and Place. Putnam didn't suppose that psychology must formulate universal exceptionless laws. Instead, Putnam held that psychological laws would take the form of statistical gneralizations. In two classic articles, "Minds and Machines" (1960) and �Psychological Predicates� (1967) (later published as The Nature of Mental States), Hilary Putnam (1926- ) formulates a slightly different solution to the problems that motivate Fiegl and Place called fuctionalism. As noted earlier, philosophers like Plato and Aristotle seem to advocate theories that are roughly characterized as functionalist. However, Putnam puts the modern face on functionalims. Putnam suggests that mental terms like pain and belief are not properly identified with some state that causes the behavioral indicators. Rather these mental terms refer to the functions that pain, belief, etc. play in the overall functioning of the organism. Specifically, Putnam suggested that physical causes of mental states (inputs), their causal relationships to other mental states, and the effects of mental states of physical states (outputs) served to definitively characterize mental states. Putnam identifies mental states with their functional characterizations, in part because, he argues, systems may come to have different states from a physiological perspective that have the same functional characterization. Such states, Putnam suggests, would be instances of the same psychological type, but instances of different physiological types. For example, if you believe that lobsters feel pain, you won't find type identity theory very satisfying becuase lobsters lack a centralized nervous system, and hence, lack the structures associated with pains in humans. This idea came to be known as multiple realizability. Ned Block (1942- ) and Jerry Fodor (1935- ) publish "What Psychological States are Not" in 1972, further articulating and defending functionalist theory. Even as Putnam articulates a synthetic, empirical functionalism, D. M. Armstrong (1926- ) published his A Materialistic Theory of the Mind. Like Putnam, Armstrong argued that mental states were best characterized by descriptions incorporating physical causes of mental states (inputs), their causal relationships to other mental states, and the effects of mental states of physical states (outputs). However, unlike Putnam, Armstrong view these descriptions as strict analyses of the concepts of our ordinary language terms that give the individually necessary and jointly sufficient conditions that the terms meaning. Finally, like Place, Armstrong viewed these descriptions as picking out the physical state that corresponded to the mental state.


Hilary Putnam (1926- )	D. M. Armstrong (1926- )	Jerry Fodor (1935- )	Ned Block (1942- )

Diagram depicting the relationships important for characterizing mental states according to functionalism. These theorists hold that a mental state is the type of state it is in virtue of its place in one�s overall cognitive economy (one�s causal nexus as described by an accurate theory), specifically the physical causes of mental states (inputs), their causal relationships to other mental states, and the effects of mental states of physical states (outputs).

The connection between functionalism and computation as well as computers traces back to Putnam's early formulations. However, starting in the late 1970s philosophers converge upon the basic explanatory schema of the CTC/RTI both as a theory of cognition and cognitive states, and as a theory of explanation and explanatory methodology. Work by Ned Block (1942- ) ["Introduction: What is Functionalism" and "Troubles with Functionalism"], Robert Cummins (1948- ) ["Functional Analysis" and The Nature of Psychological Explanation], Dan Dennett (1942- ) [Brainstorms], Jerry Fodor (1935- ) ["Special Sciences (Or: The Disunity of Science as a Working Hypothesis)" The Language of Thought], and John Haugeland (1945- ) ["Semantic Engines" and Artificial Intelligence: The Very Idea] further articulate the structure of explanations in Cognitive Science. The resulting picture is beautifully articulated in their work. The last few of these introductory lectures, outlines the salient features of this picture.


Ned Block (1942- )	Robert Cummins (1953- )	Daniel Dennett (1942- )	Jerry Fodor (1935- )	John Haugeland (1945- )

As noted in the introduction, the explanatory schema and methodology outlined ih these introductory lectures does not have homogenuous acceptance across all researchers in all the core disciplines of cognitive science. Two other views emerge in the late 1970s and 1980s. One position that emerges stems from the difficulties faced by functionalism to capture the qualitative aspects of consciousness, also called qualia. Thomas Nagel (1937- ) publishes "What it is like to be a Bat?," Frank Jackson (1943- ) publishes "What Mary Didn't Know," and David Chalmers (1966- ) publishes "Absent Qualia, Fading Qualia, Dancing Qualia." Each of these works suggest, for different reasons than Armstrong, that some if not all mental states are not physical states as traditionally understood. Nagel and Chalmers both take a page from Spinoza, and suggest that the notion of physical substance should be expanded to allow for both the traditional physical properties and mental properties. This view is known as property dualism.


Thomas Nagel (1937- )	Frank Jackson (1943- )	David Chalmers (1966- )

Diagram depicting the relationship between mental and physical properties according to property dualism. In such theories all possible properties, mental and physical, are properties of a single physical-like substance. However, mental and physical properties are irreducible to one another. Generally, such views seek to preserve the special character of mental properties, holding that scientific progress requires some new conceptual and/or scientific reconceptualization and methodological revolution.

The final view we'll consider in this lecture came to be associated with the University of California, San Diego and three philosophers who spent the early 1980s there.


Gilbert Ryle (1900-1976)	Carl Gustav Hempel (1905-1997)	Roderick Chisholm (1916-1999)	Hilary Putnam (1926- )


Patricia Churchland (1943- )	Paul Churchland (1942- )	Stephen Stich (1943- )

Diagram depicting the eliminative materialist view that ordinary mental terms constitute a folk psychology that is radically false about the nature and properties of the mind. As a result, mental properties as conceived in our folk psychology do not exist.


Map showing Miletus from http://commons.wikimedia.org/wiki/File:Miletus_Bay_silting_evolution_map-en.svg	Bust of Thales (624-546BCE) from http://www.daviddarling.info/encyclopedia/T/Thales.html

	Euclid�s Axioms 1.) To draw a straight line from any point to any other. 2.) To produce a finite straight line continuously in a straight line. 3.) To describe a circle with any centre and distance. 4.) That all right angles are equal to each other. 5.) That, if a straight line falling on two straight lines make the interior angles on the same side less than two right angles, if produced indefinitely, meet on that side on which are the angles less than the two right angles.
Euclid of Alexandria (325BCE-265BCE)	Electronic copy of Eucild's Elements	One of the oldest surviving fragments of Euclid's Elements, found at Oxyrhynchus and dated to circa AD 100. The diagram accompanies Book II, Proposition 5. From Wikipedia http://en.wikipedia.org/wiki/Euclid

Thomas Hobbes (1588�1679)	Baruch de Spinoza (1632�1677)	Rene Descartes (1596-1650)


John Locke (1632-1704)	David Hume (1711-1776)	George Berkeley (1685-1753)

Thomas Reid (1710-1796)	Immanuel Kant (1724-1804)

Donald Herbert Davidson (1917�2003)