Cognitive Computing 2012

1. Cognitive Computing 2012 Embodiment and Enactivism Hegelian arguments See: http://www.doc.gold.ac.uk/~mas02mb Professor Mark Bishop

2. Preface • In the preface Chemero outlines the structure of his book by dividing content into three core sections. • In the first section Chemero first defines, then rejects, what he terms ‘space making arguments’: • These are arguments that purport to ‘make space’ for new theory by showing a priori that the current [scientific] approaches are faulty or doomed to fail. • Chemero believes this is a ‘peculiar philosophical malady’ and one that ‘desperately needs curing’; such arguments, he says, should be taken with a proverbial ‘grain of salt’ .. • .. just as [so Chemero claims] scientists working in cognitive science dismiss arguments against the computational approach from, say, Dreyfus and Searle; • .. just as [so Chemero claims] scientists working in the ‘radical embodied cognitive science’ that Chemero champions dismiss a priori arguments against their approach. Bishop: An introduction to Cognitive Computing

3. What is radical embodied cognitive science • In the second part of the book Chemero describes radical embodied cognitive science very broadly and suggests reasons why one might be attracted to it; • Very roughly, radical embodied cognitive science is the thesis that cognition is described in terms of agent-environment dynamics and not in terms of computation and representation .. • Chemero claims that it is particularly difficult for representationalists to reject the use of representations as some entities found in cognitive agents have historically been claimed to be representations, even when they possess few [if any] of the attributes classically associated with representations. • In contrast Chemero champions the ‘dynamical thesis’: a mode of explaining perception, action and cognition without referring to representation. Bishop: An introduction to Cognitive Computing

4.  The problem of discovery • However Chemero highlights that there is a particular problem associated with dynamical cognitive science - the problem of discovery. • This problem boils down to the way in which new hypotheses are generated for testing; • In contrast the ‘background theory’ [the ‘representational theory of mind’] that defines classical cognitive science offers a [relatively] easy route to discovery via heuristic search (cf. Newell & Simon) • In the final part of the book Chemero (a) suggests Gibsonian ecological psychology offers a suitable background theory for radical embodied cognitive science and (b) clarifies just what this ecological approach is. • The three core tenets of the ecological approach are that perception is: (a) direct {contra ‘representational theory of mind’}, (b) constitutively linked to action, and (c) is of affordances {environmental ‘opportunities for action’}. Bishop: An introduction to Cognitive Computing

5.  Chapter 1: On space making arguments • Chapter 1 is concerned with warnings against space making arguments which purport to show a priori that particular scientific research programmes can never succeed. • In the chapter Chemero sets out to make sense of two related phenomena: • firstly, why there are such a large number of arguments against scientific research programmes in cognitive science but not in traditional science subjects such as, say, botany; • the second is how to explain the ‘shrug’ from the majority of scientists that listen to such arguments and are not convinced by them. Bishop: An introduction to Cognitive Computing

6.  Hegelian arguments • The chapter begins with a discussion of what Chemero calls ‘space making’ or Hegelian arguments. • Chemero describes how Hegel's 1801 book Habilitation contains an argument that the number of planets in the solar system is necessarily seven. • Hegel made this argument even in the face of contemporary evidence that there was indeed such a planet (the asteroid Ceres) between Mars and Jupiter. • Hegel’s argument was based on his investigation of one of the logical number series described in Plato's Timaeus. • Because Hegel believed a planet between Mars and Jupiter was not predicted by the series, his logic dictated that there could not be such a planet. Bishop: An introduction to Cognitive Computing

7.  Hegel’s argument • If there was a planet between Mars and Jupiter the distances between planets would not confirm to the distances predicted in [Hegel’s corrected] Timaeus number series. • Hegel’s logic dictated a priori that the distances between the planets must conform to the Timaeus number series. • Therefore Hegel concluded that there could not be a planet between Mars and Jupiter. • Therefore no eighth planet between Mars and Jupiter could ever be discovered. Bishop: An introduction to Cognitive Computing

8.  Why did Hegel believe premise 2? • Chemero reports that Hagel's reasons for believing the second premise are obscure. • Effectively Hagel - an idealist - objected to the universe being described empirically – by prediction being based on mere observation and curve fitting - and instead sought a conception of the universe based a priori on logic {pure rational thought}. • However even the interpretation of the Timaeus series to suggest that no eighth planet could ever be discovered is unwarranted, as the number series itself continues to infinity (hence leaving open the possibility must be that there could be more than eight planets). • Furthermore, as more planets were discovered, their positions conformed to the empirical curve fitting predictions not the Timaeus a priori [rational] series. • So, although in a sense Hegel's conclusion logically followed from its premises, there is serious doubt about the validity of its premises. Bishop: An introduction to Cognitive Computing

9.  Behe: on ‘irreducible complexity’ • A system with ‘irreducible complexity’ is defined as a single system which is composed of several interacting component parts that together necessarily contribute to the functioning of the system; • wherein, by definition, the removal of any one of the component parts effectively causes the system to cease functioning. • Chemero claims that, by building on the notion of irreducible complexity Michael Behe offers an argument for ‘Intelligent Design’ that that has the same a priori flavour as Hegel's. • Behe claims that an irreducibly complex system cannot be evolved by slight iterative modifications of a precursor system .. • .. because any precursor to an irreducibly complex system that is missing a component part is, by definition, non-functional. Bishop: An introduction to Cognitive Computing

10. Behe’s argument • Irreducibly complex systems cannot have evolved by natural selection. • Many biochemical systems are irreducibly complex. • Therefor many biochemical systems cannot have evolved by natural selection. • Therefore many biochemical systems must have been designed by an intelligent agent. • Chemero observes that (a) as with Hegel's argument, the conclusion is valid if the premises are valid; (b) Hagel's argument was mocked by analytical philosophers and Behe's argument is mocked by scientists. Bishop: An introduction to Cognitive Computing

11. Hegelian arguments in cognitive science:(a) Chomsky's ‘poverty of stimulus’ argument. • Language is complex: it is acquired rapidly and it is acquired without much explicit instruction. • From the above Chomsky reaches two conclusions: • that there must be an ‘innate grammar‘; • and that studying language without taking this into account is hopeless. • Chemero believes Chomsky’s conclusions laid the very foundations of ‘cognitive science’. • Cf. Newell and Simon’s ‘Physical Symbol System Hypothesis’. Bishop: An introduction to Cognitive Computing

12. Cholmsky’s argument • Children uniformly and rapidly learn a language without specific reinforcement. • Children are presented with insufficient evidence to infer the characteristics of the grammar they attain. • Learning a language is the attainment of a grammar; hence • (a) grammar must be largely innate; • (b) and any theory that does not posit such innate grammar cannot account for language learning. • The problem is that “no evidence for these premises” is provided by Chomsky. Bishop: An introduction to Cognitive Computing

13. Hegelian arguments in cognitive science: (b) Fodor and Pylyshyn's argument against connectionism • Human thought is systematic; cognitive abilities come in clusters. • Such systematicity necessarily requires representations with compositional structure • Neural networks do not process representations with a compositional structure • Therefore connectionist networks are not good models of human thought. • As premises (1) and (3) are not explicitly argued for - grounded in empirical evidence – Chemero asserts that the argument is clearly Hegelian. Bishop: An introduction to Cognitive Computing

14. What is wrong with Fodor & Pylyshyn’s argument? • In an ironic twist in F&P’s paper the only empirical work actually referred to in the text actually tells against systematicity of language.. • Furthermore others commentators have suggested that, whilst language may be systematic, the rest of human thought is not. • And other commentators have argued that neural networks can deal with compositional representations. • E.g. Nasuto and Bishop suggest NESTER as an example of a connectionist architecture which, in a sense, does process compositional data. • Chemero worries that within cognitive science these arguments are taken seriously in a way that Hegelian arguments in other sciences are not. • NB. Chemero reminds us that this claim contrasts with the earlier suggestion that scientists will ‘shrug their shoulders’ and reject Hegelian arguments; why not in cognitive science? Bishop: An introduction to Cognitive Computing

15. Why do Hegelian arguments matter in Cognitive Science ? • Chemero wonders if it is because ‘thought’ - the subject matter of cognition - is vague, insubstantial and immaterial, in a way that, say, the biological processes of digestion are not; • .. and hence requires a different kind of conceptual approach, one where Hegelian arguments have influence.. • Chemero notably observes that very few Hegelian arguments are currently deployed by practising biologists. • NB. It is interesting to note that Chemero specifically excludes Behe from the community of real biologists because he offers a ‘Hegelian form’ of argument; but does this ‘beg the question’?? Bishop: An introduction to Cognitive Computing

16. The complexity of digestion • Herbivores – employ complex foregut and hindgut fermentation in ‘vats of bacteria’. • Carnivores – employ relatively short unspecialised digestive tracts with little or no fermentation (hindgut if it occurs); and either masticate their food or use chemical digestion. • Omnivores – like herbivores, omnivores employ relatively complex digestive tracts with hindgut fermentation; like carnivores they also masticate [or, for example, use stones in their gut] to help breakdown food. • At first sight the sheer complexity of digestion makes it an unlikely candidate for a Hegelian argument .. • Chemero suggests that ‘in the absence of detailed observation and experimentation’ digestion would appear very difficult to understand from the ‘rarefied position of the philosophers armchair’ and yet there are Hegelian arguments on digestion … Bishop: An introduction to Cognitive Computing

17. On ‘multiplication theory’ • Medieval scholastics believed in multiplication theory: • Everything made of indivisible atoms. • Adam’s atoms passed down through the generations via multiplication (splitting into two). • Medieval Scholastics believed that all ‘human matter’ was formed in this way, (i.e. copying [multiplying] atoms passed down from Adam). • In this world view no new matter ever enters the body; hence digestion, a priori, cannot incorporate the substance of which we eat, as this would dilute Adam’s atoms in the body. Bishop: An introduction to Cognitive Computing

18. Why did the scholastics hold this position? • The medieval Scholastics held this argument in the face of clear evidence - that (a) over-eating makes people fat and (b) starvation made people thin - because: • It explained how "original sin" is passed down the generations [in Adams "tainted" atoms]; • It avoids a logical problem of resurrection: • If a lion eats Goliath and subsequently David [a hunter] kills and eats that lion, an incorporative digestion would suggest that some atoms of Goliath would be incorporated into David. • But if so, how would God partition these incorporated parts of Goliath from David at resurrection? • Thus, as at least one Hegelian argument has been deployed in biology, there doesn’t appear to be anything intrinsic to the subject area that rules it out a priori as a candidate for Hegelian arguments; why then do these arguments flourish in some fields of enquiry and not others? Bishop: An introduction to Cognitive Computing

19. Kuhn • Kuhn considers all scientific research to be in one of three phases: • Immaturity. • Normal scientific progress. • Revolution. Bishop: An introduction to Cognitive Computing

20. Hegelian arguments have different effects in each of these phases • In immature science (e.g. cognitive science?) the lack of a consensus theoretical background encourages Hegelian arguments • E.g. in the competition for grants and papers. • But the lack of a shared background blunts the force of deployed Hegelian arguments as their assumptions may not be shared by all practitioners (cf. Fodor and Pylyshyn; Searle). • In normal science - biology of digestion - Hegelian arguments will be rare. • In revolutionary science empirical data is incommensurate with theory; a Kuhnian ‘paradigm shift’ occurs. • In this phase we can expect negative Hegelian arguments from opponents and proponents of traditional theory. • It is Chemero's ‘bet’ that empiricists in Cognitive Science will demonstrate that more than one theoretical approach to cognition is required. • In this case perhaps Chemero is effectively “having his cake and eating it”; not really being ‘all that radical’ after all ... Bishop: An introduction to Cognitive Computing

21. Is Searle’s Chinese room a purely ‘Hegelian’ argument? • In a short paper from 1999 Harré and Wang, (J. Expt. Theo. Artif. Intell., 11: 153-154, 1999) outlined a simple experiment that attempted to empirically investigate the following question: • “To evaluate exactly what a subject actually experiences over time as she engages in an interactive, ideographic, rule-based ‘language’ game”. • Harré and Wang’s ‘language’ comprised of 13 basic Chinese ideographs and a simple rule-book for manipulating them: • Straight rules: e.g. • X {WHISKY} => Y {DRINK}. • Branching rules: e.g. • [P] {THIRSTY} + [q] {BEER?} => [r] {PUB!} • [P] {THIRSTY} + [u]{ COFFEE?} => [w] {CAFÉ!}

22. ‘Father Jack’ says ... • The Harré and Wang rules enabled simple ‘conversations’ of the following form to take place: • Speaker-1 enquires: “WHISKY?” Speaker-2 replies: “DRINK!!” • Speaker-1 enquires: “THIRSTY?” Speaker-2 replies: “BEER??” Speaker-1 concludes: “PUB!!” ** • By stating In their conclusion that • “… none of our participants reported having any sense of the meaning of the symbols” • Harré and Wang appear to empirically confirm the truth of Searle’s underlying intuition: • ‘that rule based manipulations [of un-interpreted symbols] alone are not sufficient for real understanding’. ** TV viewers from Ireland and the United Kingdom might recognise this style of conversation, so effectively deployed by Father Jack Hackett, in the Irish/British television comedy series Father Ted.

23. Computation in the CRA • Is Chemero’s critique of Searle’s CRA - as purely Hegelian - grounded on a misunderstanding of the nature of computation? • Recall, Turing conceived of the Turing Machine to be ‘an abstraction of a human computer following an effective method’. • Thus - presuming Turing was successful - there is nothing that a TM has [as it computes] that a human computer does not. • In other words does Searle [in the CRA] simulate a computation OR instantiate a computation? • If the latter, then perhaps the CRA is not so much a [Hegelian] a priori thought experiment, but more akin to an experimental protocol (cf. Harre and Wang). Bishop: An introduction to Cognitive Computing

24.  Conclusions • Chemero suggests that we should not allow Hegelian arguments to lead to inappropriate pre-emptive weeding of scientific theories… • Rather we should encourage a theoretical pluralism that allows many competing theories to flourish; • as ‘competition between theories’ forces ‘development of theory’. • But perhaps there are merely successful a priori arguments and unsuccessful ones? • Hegel’s argument BAD; Einstein and Searle’s GOOD ?? Bishop: An introduction to Cognitive Computing