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Hubert Lederer Dreyfus (born October 15, 1929) is a professor of philosophy at the University of California, Berkeley. His main interests include phenomenology, existentialism and the philosophy of both psychology and literature, and philosophical implications of artificial intelligence.

Contents 1 Background 2 Dreyfus's criticism of AI 3 Achievements 4 Further reading 5 External links

Professor Hubert Dreyfus is a contemporary American philosopher. He is considered one the world's leading analysts of postmodern philosophy from Edmund Husserl to Michel Foucault, Maurice Merleau-Ponty, and especially Martin Heidegger. He is the author of "Being-in-the-World: A Commentary on Heidegger's Being and Time, Division 1", arguably the authoritative text on Heidegger's most significant contribution to philosophy. He also co-authored "Michel Foucault, Beyond Structuralism and Hermeneutics", authored the English translation of Merleau-Ponty's "The Primacy of Perception", and authored the controversial 1972 book What Computers Can't Do, revised first in 1979, and then again in 1992 with a new introduction as What Computers Still Can't Do. While spending most of his teaching career at Berkeley, Professor Dreyfus also taught at the Massachusetts Institute of Technology (from 1960 to 1968) and at the University of Frankfurt and Hamilton College. His philosophical inquiries have influenced the thinking of Charles Taylor, John Searle, Charles Guignon, William Blattner, and many others. His critical comments on the existential phenomenology and subsequent dialectical philosophy of Jean-Paul Sartre has played a significant role in the demise of Sartre's influence on modern thought.

In 1964 Dreyfus published Alchemy and Artificial Intelligence, an attack on the work of Allen Newell and Herbert Simon, two of the leading researchers in the field of Artificial Intelligence. Dreyfus not only questioned the results they had so far obtained, but he also criticized their basic presupposition (that intelligence consists of the manipulation of physical symbols according to formal rules), and argued that the AI research program was doomed to failure. In 1965, he spent time at the Rand Corporation, whilst work on artificial intelligence was in progress there.

In addition to his work criticizing artificial intelligence, Dreyfus is well known for making the work of continental philosophers, especially Martin Heidegger and Michel Foucault, intelligible to analytically trained philosophers.

Dreyfus's critique of artificial intelligence (AI) concerns what he considers to be the four primary assumptions of AI research. The first two assumptions he criticizes are what he calls the "biological" and "psychological" assumptions. The biological assumption is that the brain is analogous to computer hardware and the mind is analogous to computer software. The psychological assumption is that the mind works by performing discrete computations (in the form of algorithmic rules) on discrete representations or symbols.

Dreyfus claims that the plausibility of the psychological assumption rests on two others: the epistemological and ontological assumptions. The epistemological assumption is that all activity (either by animate or inanimate objects) can be formalised (mathematically) in the form of predictive rules or laws. The ontological assumption is that it is an objective fact that reality consists of a set of mutually independent, atomic (indivisible) facts (see fuzzy logic). It's because of the epistemological assumption that workers in the field argue that intelligence is the same as formal rule-following, and it's because of the ontological one that they argue that humans use internal representations of reality.

On the basis of these two assumptions, workers in the field claim that cognition is the manipulation of internal symbols by internal rules, and that, therefore, human behaviour is, to a large extent, context free (see contextualism). Therefore a truly scientific psychology is possible, which will detail the 'internal' rules of the human mind, in the same way the laws of physics detail the 'external' laws of the physical world. But it is this key assumption that Dreyfus denies. In other words, he argues that we cannot now (and never will) be able to understand our own behavior in the same way as we understand objects in, for example, physics or chemistry: that is, by considering ourselves as things whose behaviour can be predicted via 'objective', context free scientific laws. According to Dreyfus, a context free psychology is a contradiction in terms.

Dreyfus's arguments against this position are taken from the phenomenological and hermeneutical tradition (especially the work of Martin Heidegger). Heidegger argued that, contrary to the cognitivist views on which AI is based, our being is in fact highly context bound, which is why the two context-free assumptions are false. Dreyfus doesn't deny that we can choose to see human (or any) activity as being 'law governed', in the same way that we can choose to see reality as consisting of indivisible atomic facts...if we wish. But it is a huge leap from that to state that because we want to or can see things in this way that it is therefore an objective fact that they are the case. In fact, Dreyfus argues that they are not (necessarily) the case, and that, therefore, any research program that assumes they are will quickly run into profound theoretical and practical problems. Therefore the current efforts of workers in the field are doomed to failure.

Given that Dreyfus has a reputation as a Luddite in some quarters, it's important to emphasise that he doesn't believe that AI is fundamentally impossible; only that the current research programme is fatally flawed. Instead he argues that to get a device (or devices) with human-like intelligence would require them to have a human-like being in the world, which would require them to have bodies more or less like ours, and social acculturation (i.e. a society) more or less like ours. (This view is shared by psychologists in the embodied psychology (Lakoff and Johnson 1999) and distributed cognition traditions. His opinions are similar to those of Rodney Brooks and others in the artificial life field.)

Erasmus University awarded Dreyfus an honorary doctorate "for his brilliant and highly influential work in the field of artificial intelligence, and for his equally outstanding contributions to the analysis and interpretation of twentieth century continental philosophy".

• 1964. Alchemy and Artificial Intelligence
• Continental Philosophy: An Introduction
• 1972. What Computers Can't Do: The Limits of Artificial Intelligence. ISBN 0-06-0011082-1)
• 1979. What Computers Can't Do: The Limits of Artificial Intelligence. (revised) ISBN 0-06-090613-8, ISBN 0-06-090624-3.
• 1992. What Computers Still Can't Do: A Critique of Artificial Reason. ISBN 0-262-54067-3)
• 1986 (with Stuart Dreyfus). Mind Over Machine. Free Press.
• 1991. Being in the World: Division 1.
• 2000. Heidegger, Coping, and Cognitive Science: Essays in Honour of Hubert L. Dreyfus. MIT Press.
• 2001. On the Internet. Routledge. ISBN 0-415-22807-7)
• 2002. Internet.

• George Lakoff and Mark Johnson, 1999. Philosophy in the Flesh: the Embodied Mind and its Challenge to Western Thought. Basic Books.

1. Professor Hubert Dreyfus
2. Recent Papers
3. Webcast: Existentialism in Literature and Film