Part A - Introduction


Introduce the long-standing debates regarding cognition

"The younger generation of physicists, ..., may be very bright; they may be more intelligent than their predecessors, .... But they are uncivilized savages, they lack in philosophical depth and this is the fault of the very same idea of professionalism which you are now defending" (Feyerabend, 1969)

Philosophy | Ancient | Modern | Current | Exercises

Moore's law does not apply to humanity and never has!  Our time gets more expensive every year and with every generation.  The tension between technological progress in the field of computing and human progress persists.  It is this fundamental stress that HCI addresses and works to reduce.  Although the solutions that HCI offers are primarily rationally motivated, they do not exclude non-rational ones. 

Everyday life changes slowly.  People's views change slowly.  Our societies and our cultures change very slowly.  Our human physiology changes extremely slowly. 

One of the most important contributions to HCI comes from our own understanding of our mental states, capacities, and processes.  This is called an understanding of cognition or the nature of how we think.  Cognition is involved in nearly everything that we do, in how we communicate amongst ourselves, and in how we interact with the objects of our own designs.  Our understanding of cognition dates as far back as two millenia.  Over the two millenia, we have refined our understanding of cognition.  Much of the knowledge that we have developed has been under the auspices of the discipline of philosophy.  With the rise of science and its stress on experimental verification, the discipline of psychology took much of this work under its own auspices.  With the advent of computer science, the discipline of cognitive psychology gained its own footing as an independent field. 

In this chapter, we review the prehistory of cognitive psychology in terms of the concepts that have evolved and are currently important in HCI.  We start with the major positions adopted by various philosophers, continue through the positions adopted by different psychologists, and conclude with a description of some of the views currently held.  This background information provides the context for evaluating and situating many of the diverse topics introduced in later chapters. 


What we share with computers is rational behavior.  What distinguishes us from computers are our moral principles, our cultures, our aesthetics, our ethical orientations, and our emotions, to name a few. 

Describing humanity rationally is the domain of philosophy.  Philosophy in Greek means the 'love of wisdom'.  Philosophy articulates our insights into the nature of our humanity.  Interest in philosophy has increased notably in recent years in the United States according to the New York Times.

Philosophy involves the study of fundamental problems through reason and argument.  The branches of philosophy include (Wikipedia):

  • philosophy of mind - the study of mind and its relationship to the body
  • aesthetics - the study of perception, art, taste, and sentiment
  • logic - the study of valid forms of reasoning
  • philosophy of language - the study of forms of communication
  • ethics - the study of goodness, how persons ought to act
  • political philosophy - the study of justice, law, property, and rights
  • epistemology - the study of knowledge (truth, belief, and justification)
  • metaphysics - the study of being and the cosmos
  • philosophy of science - the study of the assumptions, methods, and implications of science
  • philosophy of religion - the study of myths, beliefs, and traditions

The highlighted branches - philosophy of mind, aesthetics, logic, philosophy of language, and ethics - have all contributed to the knowledge base of HCI.  The following historical notes summarize a few bits of wisdom that have passed down to HCI. 

Ancient Philosophy


Plato (428BCE - 348BCE) was a Greek philosopher who lived in Athens and Syracuse and founded one of the earliest schools in Western civilization.  He was a student of Socrates and the teacher of Aristotle.  He developed Socrates' theory of forms - that is non-material abstract ideas - are known to us through sensation and possess the highest kind of reality.  To Plato, forms are the only true objects of study.

Plato described the concept of innateness.  In the Meno dialogue, he writes that Socrates, who is speaking with an uneducated servant, interrogates the servant.  Through this interrogation, Socrates shows that the servant knows the Pythagorean theorem.  To Plato, this could only be possible if people are born with some innate knowledge. 


Aristotle (384BCE - 322BCE) was a Greek philosopher during the one of the largest empires in ancient history, which stretched from the Adriatic Sea to the Indus river.  He was a student of Plato and the teacher of Alexander the Great.

Aristotle distinguished practical and theoretical reasoning.  Practical reasoning is about what to do, while theoretical reasoning is about what is.  Practical reasoning involves goals and purposes, while theoretical reasoning involves causes.  We say that practical reasoning is teleological and theoretical reasoning is mechanistic. 

Aristotle understood perception as the process of taking the essential structure of the perceived object into the mind. He wrote that "nothing is in the mind that is not first in the senses".  That is, he thought that the essential structures literally move into our minds.

Modern Philosophy


Rene Descartes (1596-1650) was a French philosopher during the Thirty Years War between the Protestants and the Catholics in the Holy Roman Empire.  The Empire was in its descendancy and freedom of religious belief was starting to gain ground. 

Descartes identified the mind as a "thing that thinks".  He identified the materials with which it thinks as representations and in this sense broke with Aristotle's view.  Descartes introduced

  • the notion of a representation
  • the idea that representations are in the head
  • the idea of the mind as a unified system of representations

The idea of the mind as a unified system existing on its own is sometimes called the Cartesian Theater and remains dominant in cognitive science.  To Descartes, knowledge was the result of reflection more than the result of observation.

Descartes is famous for the quote "I think, therefore I am".  He doubted everything, but this he could not doubt.  This became his point of certain departure.  He placed more emphasis on the mind and less on the senses and was the father of rationalism.  Rationalists trusted those representations that were arrived at entirely inside the mind through reasoning alone. 

Descartes is known for the mind-body split.  To Descartes, a person was the unity of two kinds of things that were utterly different.  Few philosophers ascribe to this view nowadays.  Many consider him the founder of modern philosophy.  Chomsky considers his period to be the first cognitive revolution. 


Thomas Hobbes (1588-1679) was an English philosopher and contemporary of Descartes.  He spent many years in Paris during the English Civil War.  The royalist cause was in its descendancy.  While a champion of sovereign absolutism, he developed some of the fundamentals of liberal thought, including the view that all legitimate political power must be 'representative'.

Hobbes articulated the notion that thinking is operations that are performed on representations.  With Descartes, he was responsible for identifying the mind as a system that contains representations and is a system for manipulating them.  That is, cognition consists of computations over representations. 

Hobbes disagreed with Descartes on the nature of the mind itself.  To Hobbes, the mind was the brain: "all reasoning is but reckoning".  Many consider him the founder of mechanical materialism.


Baruch Spinoza (1632-1677) was a Dutch philosopher who worked as a lens grinder and turned down rewards and honours throughout his life.  He fell out with the Jewish community because of his views on the Hebrew Bible and the nature of the Divine.  His books were also put on the Catholic Church Index of Forbidden Books.  His ancestors were of Sephardic Jews descent and part of the Portuguese community that lived in Amsterdam after the Portuguese Inquisition.  The philospoher Hegel later said of all philosophers "You are either a Spinozist or not a philosopher at all."

Spinoza opposed Descartes' mind-body dualism and argued that they were a single substance.  Emotion cannot be overcome by reason, only by stronger emotion.  Knowledge of the ture causes of passive emotion can transform it into active emotion; that is, emotion supported by reason.  In this, he anticipated one of the key ideas of Freud's psychoanalysis. 

Spinoza was a thoroughgoing determinist who held that everything occurs through the operation of necessity.  Even human behavior is fully determined.  For Spinoza, everything done by humans is excellent and divine.


Gottfried Liebniz (1646-1716) was a German philosopher and mathematician.  He invented a variety of calculators and refined the binary number system.  He was the most important logician between Aristotle and George Boole and Augustus deMorgan.  The principles of his logic reduce to:

  • all ideas are compounded from a very small number of simple ideas
  • complex ideas proceed from simple ideas by uniform and symmetrical combination

Descartes, Spinoza, and Liebniz are considered the founders of Rationalism.


John Locke (1632-1704) was an English philosopher and physician, who lived during the English Civil War and the English Restoration, and who wrote in the aftermath of the European wars of religion.  He advocated the separation of church and state and his writings were a dominant influence on the Founding Fathers of the United States.  His Essay Concerning Human Understanding is considered by some philosophers as marking the beginnning of the modern Western conception of self. 

Locke held that the mind was a blank slate or "tabula rasa", that we are born without innate ideas, and that our knowledge is determined solely by experience derived from sense perception.  For Locke, sensations and reflections were the two sources of all of our ideas.  He held that associations of ideas made during youth are what marked the person. That is, first impressions matter most. 

Locke is considered the father of the British empiricists.  Empiricists emphasize the importance of experience, particularly sense perception, over innate ideas or traditions.


George Berkeley (1632-1704) was an Anglo-Irish philosopher and theologian, who lived in Dublin, Ireland, Newport, Rhode Island, and London, England.  He advocated the principle that the world, as represented by our senses, depends for its existence, as such, on being perceived.  One of his main objectives was to combat the prevailing materialism of his time.

Berkeley held that familiar objects are only ideas in the mind of perceivers - "to be is to be perceived".  To Berkeley, knowledge consists of ideas and spirits, where spirits cannot be perceived. 

Berkeley founded subjective idealism.  He was a great spokesman of empiricism and the father of idealism.  He was the first philosopher to treat seriously the mind as a starting point. 


David Hume (1711-1776) was a Scottish philosopher and essayist who lived during the Scottish Enlightenment.  He was an atheist, very critical of the Catholic Church and of the extreme Protestant sects, who believed in the experimental method and loated superstition.  He was a contemporary of Adam Smith, the father of modern economics and capitalism.  Hume pioneered the essay as a literary genre.

Hume held that there is no source of knowledge except sense experience.  He also held that sensible representations are like pictures, not propositional structures, and associations govern their relationships, not propositional relations.  By insisting even more rigidly than Descartes that everything about the content of representation is in the head, he formulated the internalist view that is still common place today. 

Hume circumscribed reason's role: "Reason is, and ought to be the slave of the passions, and can never pretend to any other office than to serve and obey them." Hume held that our natural instinct is the basis of our ability to form inductive inferences.  That is, induction cannot be logically justified.  Reason cannot provide any certainty even for our most mundane beliefs.

Locke, Berkeley, and Hume are considered the founders of Empiricism.

Jerry Fodor has proclaimed Hume's "A Treatise of Human Nature" the founding document of cognitive science.


Immanuel Kant (1724-1804) was a German philosopher who lived in Konigsberg, the capital of Prussia at the time.  He wrote the Critique of Pure Reason, which is now considered one of the most influential works in the history of philosophy.  He developed the doctrine of transcendental idealism, which maintains that our experience of things is similar but not identical to the way that they appear to us.  In other words, human experience is not an activity that directly comprehends the things as they are, but involves an active human subject. Kant placed the human subject at the centre of the cognitive and the moral worlds.  For Kant, human beings are to be treated as ends rather than as means. 

Kant brought together empiricism and rationalism.  He developed the first non-empiricist critique of rationalist philosophy, by placing the human subject at the center of both cognitive and moral perceptions.  Kant argued that the element of knowledge advocated by rationalism and the element advocated by empiricism are both necessary.  To acquire knowledge, we need both sensible input and activities of the mind.  "thoughts without content are empty, intuitions without concepts are blind".  We cannot confirm or disconfirm conceptualizations without experimental evidence, no matter how carefully we think about the conceptualizations, but we cannot organize experience without applying concepts to it.  To Kant, accumulation of sense perceptions was not enough.  Our intuitions of space and time are forms of sensibility that are a priori necessary conditions for experience.  To Kant, synthetic propositions do not necessarily require sense experience.  For example, arithmetic provides new knowledge but is not derived from experience. 

Kant clarified the concept of unity of consciousness.  We experience a combination of sensations as one single conscious experience, not as a sequence of isolated experiences.  For the experience to be a unified conscious one, we must be able to apply certain concepts to the objects of our experience.  This view has yet to be incorporated into cognitive science. 

A great majority of cognitive researchers hold to a model of the mind that is Kantian in many respects.  In this sense, Kant can be viewed as the grandfather of cognitive science. 

Kant's solution created a new set of problems.  By limiting knowledge to the world of physical objects, moral duties and reflection of trancendental conditions took second place.  This eventually led to a new kind of dogmatism and a new kind of skepticism.


Georg Frederick Wilhelm Hegel (1770-1831) was a German philosopher who lived in Germany during the French and American revolutions, the Reign of Terror, and Napoleon's invasions of Europe, when Germany was weak and looking to reinvent itself.  He was one of the creators of absolute idealism, which describes the progress from sense perception to absolute knowledge.  Hegel asserted an identity of thought and being.  He showed that we do not relate to the world as if it is outside ourselves, but continually find ourselves back in that world through human history.  Hegel introduces human history into the evolution of thought.

Hegel presents a history of human consciousness as a journey through rational stages of explanations.  Each stage creates problems and oppositions within itself and we accommodate the oppositions by finding a higher unity.  We need to step through each stage to move to the next.  Hegel claims that self-consciousness can only be realized through the self-consciousness of another. 

Here is a 32-minute lecture on Hegel's Phenomenology of Spirit (or Mind)


Charles Sanders Pierce (1839-1914) was an American philosopher who worked as a scientist for 30 years and founded the philosophical tradition of Pragmatism, which links theoretical reason with practical reason.  Pierce believed that truth was both independent of actual opinion and discoverable.  He believed that rational concepts necessarily go beyond data. 

Pierce held that inductive reasoning and deductive reasoning are complementary rather than competitive modes of thought.  He introduced abductive reasoning.  For Pierce, the objects of our knowledge are real and their properties do not depend upon our perceptions; everyone with sufficient experience will agree on the truth about these objects.  For Pierce, science is both fallible and self-corrective.

Pierce's pragmatic maxim states: "Consider what effects that might conceivably have practical bearings you conceive the objects of your conception to have.  Then, your conception of those effects is the whole of your conception of the object."  Pragmatism begins with the idea that belief is that on which one is prepared to act.  It distinguishes conceptual confusions into those that have no practical differences and those that have practical differences. 

Pierce's pragmatism moved beyond the debate between rationalism and empiricism; that is, beyond deduction from self-evident truths and induction from experiential phenomena.  He envisaged a three-phase dynamic of inquiry:

  • Abductive - genesis of theory, with no prior assurance of truth
  • Deductive - application of contingent theory to clarify its practical implications
  • Inductive - testing and evaluation of provisional theory's utility for anticipation of future experience - prediction and control

For Pierce, a theory that succeeds better than its rivals in predicting and controlling our world is said to be nearer the truth.  Abduction, deduction, and induction comprise a cycle as they collaborate toward the end of an inquiry.  Everything has a purpose and the purpose is the first thing that we should try to note about it.


Gottlob Frege (1848-1925) was a German mathematician who became a logician and philosopher.  He is one of the founders of modern logic and as a philosopher, he is considered to be the father of Analytical Philosophy, which emphasizes the use of scientific methods to develop and solve philosophical problems.  Frege set out to show that mathematics grows out of logic.

Frege invented predicate logic, which solved the problem of multiple generality.  Traditional logic had dealt with and, or, if...then..., not, some, and all as single qualifiers.  Sentences with multiple qualifiers, such as some and all, could not be adequately represented. Frege's formalism had no difficulty expressing these iterations.  Frege removed intuition from mathematical proofs, relegating it to an axiom. 


Bertrand Russell (1872-1970) was a British mathematician, logician, and philosopher.  He led the British revolt against idealism and co-authored "Prinicipia Mathematica" in an attempt to ground mathematics on logic.  His work has had considerable influence on logic, mathematics, computer science (type theory and type systems), and philosophy. 

Russell was one of the founders of modern logic.  As a philosopher, he is considered to be the father of Analytical Philosophy, which emphasizes the use of scientific methods in developing and solving philosophical problems. 

Here is an hour long Interview with Bertrand Russell on philosophy in general.

Ludwig Wittgenstein

Ludwig Wittgenstein (1889-1951) was an Austrian philosopher who held a professorship at the University of Cambridge until 1947.  He was a proponent of the ordinary language philosophy, which focused attention on the details of the use of everyday language, as opposed to ideal language philosophy.  The young Wittgenstein, along with Gottlob Frege and Bertrand Russell were main influences on the early logical positivist movement.

Here is a 4-minute video of Derek Jarman's production of Wittgenstein: This is a very pleasant pineapple

Vienna Circle and Logical Positivism

The Vienna Circle was an association of philosophers around the University of Vienna in 1922, who shared the view of philosophy known as logical positivism.  Logical positivism combines empricism and rationalism in such a way as to exclude all a priori (from before) propositions as having no meaning.  From the early 20th century until the 1950s it was the leading school in the philosophy of science.  It advocated the codification of all knowledge in one single standard language of science. 

These philosophers used the formalism of Bertrand Russell and Ludwig Wittgenstein to underpin their empiricist view of the world, claiming that scientific truths were verifiable claims and that anything else was nonsense.

Here is a 9-minute interview of A.J.Ayer on Logical Positivism


Karl Popper (1902-1994) was an Austro-British philosopher of science who advocated the theory of empirical falsification.  He was a major critic of the verificationism


Paul Feyerabend (1924-1994) was an Austrian-born philosopher of science who served in the German army during the Second World War and who studied under Popper after Wittgenstein died.  He broke with contemporary rationalist culture in the philosophy of science to reject all universal methodological rules in science and to advocate an anarchist or dadaistic theory of science where "anything goes".  He believed that science would benefit most from a healthy dose of theoretical anarchism.

Feyerabend influenced the development of eliminative materialism Eliminativists claim that modern beliefs in the existence of mental phenomena are mistaken beliefs that will eventually be replaced

Here is a 9-minute Interview of Mario Bunge on the Popperians

Current Philosophy

Current philosophy includes a deep division between post-modernists and modernists.  The debates related to cognitive science include that between connectionism and computationalism.

Post-Modernism and Modernism

The idea of post-modern philosophy arose in the 1940s primarily in France.  Post-modernists view human development as having left modernity behind and entered into a post-modern condition.  Many see modernity as having ended in the late 20th century, where modernity is seen as the failed attempt to incorporate principles of rationality and hierarchy in the pursuit of progress. 


Jacques Derrida (1931-2007) was an Algerian-born French philosopher who developed the critical theory of deconstruction and is associated with post-modern philosophy.  Post-modern philosophy is skeptical of assumptions that claim that humans have an essence that distinguishes them from animals. 

Derrida asserted that there is nothing outside the text or that there is nothing outside context.  His work stands out as a direct challenge to the Analytical tradition of philosophy as well as to Continental philosophy in general. 


Richard Rorty (1931-2007) was an American philosopher who rejected his analytic background in favour of his own brand of pragmatism.  He considered representational accounts of knowledge a holdover from Plato's views and rejected them.  Rorty has been called a neo-pragmatist.

Rorty focused on the works of Nietzsche, Hiedegger, Foucault, Lyotard, and most recently Derrida.


Hilary Putnam (1926-present) is an American philosopher, mathematician, and computer scientist and a central figure in Analytical Philosophy.  He has argued against the type identity of mental and physical states.

Here is a 9-minute video on the Rorty-Putnam Debate


Jurgen Habermas (1929-present) is a German sociologist and philosopher who developed the critical theory of communicative rationality and is associated with Continental philosophy and the continuing research project of Modernism.  This project attempts to reveal the possibility of reason and rational-critical communication in our existing organizations and institutions. 

Habermas identifies internal reason in interpersonal communication as the feature that distinguishes humans from animals and enables them to achieve communicative competence.

Here is a rare 5-minute interview with Jurgen Habermas

Connectionism versus Computationalism

Connectionism models mental phenomena as emergent processes of interconnected networks of simple units.  These units resemble neurological structures.  Information is stored in the form of connections between neurons.  Computationalism models thought as a computation; that is, that mind functions as a symbol manipulator, where the symbolic models do not resemble underlying brain structure. 


Paul Churchland (1942-present) is a Canadian-born philosopher who works in the United States and is a major proponent of eliminative materialism.  He argues that a future neuroscience is likely to have no need for beliefs or fellings and that even consciousness and personal identity are suspect. 

Patricia Churchland (1942-present) is a Canadian-born philosopher who works in the United States and has contributed to the field of neurophilosophy.  She argues that common-sense, immediately intuitive concepts such as though, free will, and consciousness will need to be revised in a reductionistic way as neuroscientists discover more about the nature of brain function. 

These concepts will be eliminated due to their lack of correspondence to measureable phenomena.  As examples, he uses phlogiston, caloric, ether, and vital forces, which were all eliminated. 


Jerry Fodor (1935-present) is an American philosopher and cognitive scientist of the Analytic school of philosophy.  He holds that beliefs and desires are relations between individuals and mental representations.  He views thinking as computations operating on the syntax of the representations that make up the language of thought.  He developed a strong commitment to the idea of psychological nativism. 

Fodor proposed the language of thought (LOT) hypothesis, which describes thoughts as repesented in a language that allows building of complex thoughts from simpler thoughts; that is, thought has syntax. 

LOT is a rationist model of cognition that challenges both eliminative materialism and connectionism.  LOT implies that the mind has some knowledge of the logical rules of inference and the linguistic rules of syntax.  Fodor argued that it is a law of nature that cognitive capacities are productive, systematic, and inferentially coherent. 


  • Identify the major traditions in philosophy and categorize the different philosophers into those major traditions
  • Discuss your own views with a colleague and identify the general concepts with which you yourself are comfortable as well as those concepts with which you disagree