1 Meta-Representation, Mirroring and the Liar: Complex Strategic Behaviour and Arms Race In Novelty and Surprises Sheri M. Markose1 Economics Department and Centre for Computational Finance and Economic Agents (CCFEA) Email:scher@essex.ac.uk, University of Essex, Wivenhoe Park Colchester C04 3SQ, UK. June 2012 Abstract: Oppositional or contrarian structures, deception, self-reference and the necessity to innovate to out-smart hostile agents in an arms race are ubiquitous in socio-economic systems, immunology and evolutionary biology. However, such phenomena with strategic innovation are outside the ambit of extant game theory. How can strategic innovation with novel actions be a Nash equilibrium of a game? Having reviewed evidence from cognitive social neuroscience and neuro-economics, this paper shows how the only known Gödel-Turing-Post (GTP) axiomatic framework on metarepresentation of procedures singles this out as a necessary condition for self-referential simulations. Logical implications of such ‘mirroring’ include the detection of negation or deception and the capacity of such agents to innovate, “think outside the box” and embark on an arms race in novelty or surprises. The only recursive best response function of the game that can implement strategic innovation in a lock-step formation of an arms race is the productive function of the Emil Post (1944) set theoretic proof of the Gödel incompleteness result. Keywords: Meta-representation; Self-reference; Contrarian; Simulation; Strategic innovation; Novelty; Surprises; Red Queen type arms race; Creative and Productive Sets; Productive function ; Surprise Nash Equilibrium I’m grateful for recent discussions with Peyton Young, Aldo Rustichini, Kevin Mc Cabe, Steve Spear and Michael Arbib. Over the years, there have been discussions with Ken Binmore, Arthur Robson and Vela Velupillai. The paper has benefitted from feedback from participants at invited lectures given at the Kiel Institute of the World Economy in 26-27 June 2012, the Ruhr Bochum Economics Department on Markets as Complex Adaptive Systems in 2010, the Institute for Advanced Studies at Glasgow workshops on “Limits to Rationality in Economics and Financial Markets“ in June/July 2009 and from 2002 at the Centre for Computational Finance and Economic Agents at the University of Essex. 1 2 1. Introduction In a recent paper on strategic behaviour, Crawford (2003) begins with the elaborate subterfuge involved in the D-Day Allied landings of World War II in order to surprise and wrong foot the enemy. There is a long standing tradition, albeit an informal one, in the macro-economic policy literature of Lucas (1972) on the strategic use of ‘surprises’ by policy makers against a private sector which may render policy ineffective if policy can be predicted. 2 Binmore (1987) seminally indicated that any strategist who upholds deterministic strategies as being optimal must answer the question “what of the Liar ?” He had raised the alarm for game theory regarding the logical and strategic necessity for novelty that arises from the archetype of the rule breaker or contrarian who controverts or falsifies what can be computed / predicted. Baumol (2002, 2004), in keeping with the Schumpeter (1934) vision of ‘creative destruction’, has extensively discussed and documented the role of the relentless Red Queen3 type strategic arms race in innovation by firms of products and processes in capitalism which he claims is not addressed in mainstream economics. In social neuro- science, the role of social proteanism has been discussed at length when predictability is punished by hostile animals capable of prediction (see, Driver and Humphries, 1988, Miller,1988, Bryne and Whiten, 1988,1997). Markose (2004, 2005), in the context of markets as complex adaptive systems, and Robson (2003, 2005) in regard to of strategic rationality and how the human neo-cortex grew big, have argued that much of game theory overlooks the arms race in complexity and the endogenous emergence of innovations from the strategic interaction of intelligent agents. The contrarian need not only appear in the agency of a player. It can arise from the structure of the payoffs of a game where a player wins only if his actions 2 Despite, the seminal inclusion of the necessity of surprises by Lucas (1972) in a policy context in response to regulatees who can contravene policy, it was the exact opposite that was followed. The notion of a surprise strategy in the macro-economics literature appears in the so called Lucas surprise supply function which entails a term for surprise inflation. The idea here is that the private sector contravenes the effects of anticipated inflation, viz. the neutrality result. Hence, it is intuitively asserted that authorities who seek to expand output beyond the natural rate need to use surprise inflation. As surprise inflation sounds like a ‘bad’ thing to do – the objective of mainstream monetary policy for over two decades became one of pre-committing authorities to a fixed currency peg till it got destroyed by regulatees in 1992, and thereafter a fixed quantitative rule for inflation control became the sole macro-economic policy tool for stability (see, Markose, 2005 Sections 3 and 4). Remarkably as Axelrod (2003) said that system failure occurs because “coevolution is not anticipated”, the 2007 financial crisis is acknowledged by many to be the consequence of a system left vulnerable to the proteanism of regulatees by flawed micro-financial and macro-economic policy doctrines. 3 The Red Queen, the character in Lewis Carol’s Alice Through the Looking Glass, who signifies the need ‘to run faster and faster to stay in the same square’ has become emblematic of the outcome of competitive co-evolution for evolutionary biologists in that no competitor gains absolute ground. Baumol (2002) shows how Red Queen type arms race in product or process innovation is undertaken by firms simply to retain status quo in market share. 3 diverge from that of co-players. The classic zero-sum 2-person game of matching pennies is an example of this. The earliest discussion of this is by Morgenstern (1935) in terms of the mortal combat between Moriarty and Holmes. Moriarty who seeks the demise of Holmes has to be in proximity with him while Holmes needs to elude Moriaty. Arthur (1994) noted that asset markets have a contrarian pay off structure, rewards tend to accrue to those agents who are contrarian or in the minority. That is, if it is most profitable to buy when the majority are selling and sell when the majority are buying, then if all agents act in an identical homogenous fashion having made predictions from the same meta-model, they will fail in their objective to be profitable and any trend movements in prices will be broken down by contrarians who will arise endogenously from untagged agents, Arthur et. al. (1997).4 The lack of effective procedures to determine winning strategies in games with contrarian payoff structures and the impossibility of homogenous rational expectations, cleverly identified by Arthur (1994) in the above informal statement of this problem in stock markets is typically called the Minority or El Farol game. So unlike the traditional no trade results of Milgrom and Stokey (1982) and a cessation of trade under conditions of homogenous rational expectations, there is instead heterogeneity of beliefs and myriad technical trading strategies that will endogenously bring about the boom and bust dynamics seen in asset markets. Few economists have acknowledged that the 1987 Binmore critique of game theory based on the Liar, the Baumol type characterization of technology races, the Lucas ‘surprise’ based postulates for policy design and Arthur’s (1994) challenge to the possibility of homogenous rational expectations in contrarian/minority stock market games, signify the need for a new set of logico-axiomatic foundations for handling self-referential mappings of meta-representational systems and the role of protean strategic behaviour that involves novel objects not previously there. One is confronted with the disjunction between game theory on the one hand and strategic behaviour on the other in which outsmarting others using deceit, novelty and surprises are key ingredients. As partly indicated by Binmore (1987) extant mathematics of game theory is closed and complete. It is impossible to produce novelty or surprises in 4 A lucid statement of the problem of self-reference in asset markets can be found in Arthur et. al (1997) : “In asset markets, agents’ forecasts create the world that agents are trying to forecast. Thus, asset markets have a reflexive nature in that prices are generated by traders’ expectations, but these expectations are formed on the basis of anticipation of others’ expectations. This reflexivity, or self- 4 a Nash equilibrium, let alone the structure of an arms race in strategic innovation. In game theory there are strategy mappings to a fixed action set and indeterminism extends only to randomizations between given actions. Regarding contrarian behaviour, the Liar/deceit and strategic innovations or surprises to escape from hostile agents, as pointed out by Crawford (2003) –to date , economic “theory lags behind the public’s intuition”... and “we are left with no systematic way to think about such ubiquitous phenomena”. While surprise is an affective state elicited in response to an unexpected event or in the detection of a contradiction or conflict between a new discovery and a previously held theory, the significance of surprise and its associated cognitive processes in humans in the context of survival in a complex and dynamic environment is far from well formulated. The objective of this paper is to provide the only known logical and axiomatic foundations of meta-representational systems (MRS, here after), viz. the GödelTuring-Post (GTP) theory of computation or recursion function theory. It will be shown that mathematical logic naturally provides the framework for a game which involves a contrarian or oppositional structure and also on what constitutes a surprise in mutual meta-analysis involving two players. Meta-analysis in the GTP framework involves offline operations on encoded information. In preparation for this, in Section 2, a brief survey will be made of the two areas that have to date contributed to conjectures and hypotheses relating to the capacity for meta-representation and mirroring, the simulation theory of mind reading, the identification of deceit or the contrarian and the necessity to surprise and resort to protean innovative behaviour in an interactive setting. The first of these covers recent developments in cognitive and social neuroscience which includes neuro-economics of strategic behaviour. The second area is that of the applications, to date, of recursion function theory to game theory. Recent advances in the neurophysiology of the brain on mirror neurons, hailed as one of the great discoveries in science, provide a cellular explanation for why the capacity of meta-representation with self as both an actor and observer in the mapping is essential for social and strategic behaviour. In the macaque monkeys, where this phenomena was first found by the so called Parma group (Rizzolatti et. al., 1996)5, referential character of expectations, precludes expectations being formed by deductive means (italics added), so that perfect rationality ceases to be well defined”. 5 While single-cell recordings of F5 neurons have thus far been limited to monkeys, a variety of 5 mirror neurons discharge when the subject observes goal-directed action in another individual and also when performing the action herself. Hence, they serve to internally "represent" an action, by self or another, within the pre-motor cortex of the observer in the form of an offline simulation. The neurons that fire to execute the action by the agent herself, in contrast, have been called canonical neurons, Fagg and Arbib (1998).6 The ‘meta’ or virtual status attributed to mirror neurons distinguishes them from the functioning of the canonical neurons. This has led to the mirror system hypothesis (Arbib and Rizzolatti,1997, Rizzolatti and Arbib,1998) and also to the simulation theory of mind reading (see, Gallesse and Goldman,1998)7. The hypothesis here is that an individual can recognize goal oriented actions of others because the neural pattern elicited in the observational meta system of the individual is similar to what is internally generated by the canonical neurons to physically produce a similar action by the individual. Initially, the proponents of the mirror system hypothesis were careful only to attribute syntactic machine learning qualities to the activation of mirror neurons per se in the case of biological motion rather than affective understanding in humans which requires a larger repertoire of interconnections that trigger internal states linked to memory and emotions emanating from the limbic system which are all further mediated by chemical/hormonal neurotransmitters (see, Cohen, 2005). Now there is evidence that the emotional centers of the brain also have mirror-like systems such that observation of emotions in others activates the same neuron systems as in the case when the person actually experiences the emotion (Singer et. al., 2004, and Wicker et. al., 2003).8 This paper aims to use the GTP framework to construct a Nash equilibrium of a two person game with an oppositional structure in which the only logically consistent and strategically rational thing to do is to innovate or surprise in a sequence evidence derived from EEG and fMRI exists to support the claim of the homologous brain region in humans serving similar functions (see,Fadiga et al., 1995, Rizzolatti and Craighero, Iacoboni et. al., 2005). 6 Grézes et. al (2004) have mapped the respective areas of activation for some canonical functionalities and their corresponding mirror neurons in the human brain. Mulamel et. al. (2010) have obtained direct evidence from individual neurons of mirror activity and they find that mirror neurons are widespread in the brain accompanying the myriad canonical activities of humans. 7 For the most recent set of reviews on where this field is at, see http://www.psychologicalscience.org/index.php/publications/observer/2011/july-august-11/reflecting-onbehavior-giacomo-rizzolatti-takes-us-on-a-tour-of-the-mirror-mechanism.html 8 Same regions of the insula and anterior cingulate cortex are activated both with the experience of disgust and when observing others 6 which also entails an arms race. Section 3 sets up the mathematical preliminaries for a recursive function approach to analyse decision problems within a 2-person finite game. Actions involve encodable procedures that can always be executed in finite time and these will be modelled as total computable functions. The productive function of Post (1944) will form the basis of novelty production and hence the surprise strategy will be defined in terms of this. In Section 3, it will be shown how meta-representation of the full gamut of procedures is done and how meta-analyses which involves offline simulations for the prediction of the outputs of the game uses a 2 place notation based representation of players’ actions. For this a framework well known as Gödel meta mathematics (see, Rogers,1967) is used which implements a 11 mapping between executable calculations made by players and their respective meta representations. The analogy with the canonical neurons and the mirror neurons can be made here. The diagonal alignment in the meta system is shown to correspond to potential Nash equilibria of a game. Section 4 proceeds with the specification of a two person game with the classic oppositional structure of the Moriarty-Holmes game which also characterize the parasite-host or regulator-regulatee games. As already noted, the second of these twosomes have to conduct ‘deceit’ to evade the first and will apply what will be called the Liar strategy. The first significant point is that the Liar can win only out of equilibrium when the identity of the Liar is not known or the formal structure of the game involving the Liar is not acknowledged by the other player. From the perspective of the Liar, the success of his strategy requires that the first player has a false belief about the Liar. This has the self-referential second order belief structure that underpins deceit, Bhatt and Carmerer (2005). The Second Recursion Theorem is used to determine the Nash equilibria of the game as fixed points of recursive functions. When there is mutual or common knowledge of the Liar, the point at which this occurs is the famous non-computable fixed point at which a hostile agent qua Liar “knows that the other knows that he is the Liar”. This also has the self-referential second order belief structure discussed in Bhatt and Carmerer (2005) except that it entails mutual beliefs on the need for deceit. This is a major point of departure from standard game theory. It will be shown that the only best response function, within the class of recursive functions, from the mutually deducible non-computable fixed point is the Emil Post productive function which implements novel objects. This also provides proof of a fully deducible fixed point at which agents mutually infer that 7 they must surprise the other. This is a result that cannot be obtained without the GTP framework. As recursive functions are used in recombining encoded information, novelty refers to new blueprints for technologies/actions not previously there. This results in the Type IV novelty based structure changing dynamics of complex adaptive systems which is distinct from chaotic dynamics. A brief concluding section will summarize the results and directions of future work. 2. Review of Meta-representation and Protean Strategic Behaviour in Cognitive and Social Neuro-Science and in Mathematical Logic 2.1 Meta-representation and the mirror neuron system Unlike, neural competences that enhance individual functionality regarding vision, memory and even reward systems to food - the mirror neuron system (MNS) is solely oriented to equip an individual for social interaction. It is the fact that the MNS system with encoded goal related action information which exists separately from the machinery for its physical execution has a two place structure involving self and others which warrants study by game theorists. Game theory and strategic behaviour whether cooperative or non-cooperative presuppose mutual mentalizing of others’ intentions, beliefs and ‘types’. On the MNS basis of mentalizing about others, many cognitive and social neuroscientists have subscribed to the simulation theory of understanding goal related actions of others. On the role of mirror neurons, Ramachandran (2006) reiterates the Gallesse and Goldman (1998) hypothesis on the simulation theory of the mind: “It's as if anytime you want to make a judgement about someone else's movements you have to run a VR (virtual reality) simulation of the corresponding movements in your own brain and without mirror neurons you cannot do this.” The narratives of those espousing the MNS hypothesis is that understanding others involve self-referential meta-calculations arising from encoded neural imprints emanating from agent’s own execution of procedures via the canonical neurons. Further, Ramachandran (2006) views Machiavellian behaviour, über intelligence, deceit and creativity as being part and parcel of this capacity for meta-representation. In addition to MNS associated with biological movement (especially of con-specifics), the question is whether the latter only informs judgements or mentalizing (see, Grézes et. al, 2004, Centelles et. al. 2011) about others beliefs or whether there is a separate MNS for drawing a congruence between own beliefs and 8 others beliefs of one’s beliefs. Oberman and Ramachandran (2004) suggest that a system of neurons in the medial prefrontal cortex9 may serve as the mirror-like shared representation for the experience and perception of mental states (Ochsner et. al. 2004). The neuroscience of how a mental simulation framework operates when two people directly interact10 is still in its infancy and possibly neuro-economic game theorists are leading the way here. 2.2 Protean strategic behaviour and the role of deceit in social neuro-science and neuro-economics There is a growing social neuroscience literature (see, Grammar et. al. 2002) which hypothesizes that MNS provide the neurophysiological basis of ‘the shared manifold’ for inferential communication in society. Many (see, Sperber, 2000) hold the capacity for meta-representations as the prime faculty in humans and adduce from this much credence for the hypothesis of an evolutionary arms race in higher order meta-representational abilities that has been called ‘Machiavellian intelligence’ by Bryne and Whiten (1988), Whiten and Bryne (1997). The evolution of deception in animals and primates in environments with conflicting goals and the detection of falsity have been identified as an important landmark of meta-representational competence in humans (see, Baron-Cohen 1995).11 Miller (1997) has catalogued deceitful behaviour to combat situations with the potential for conflict as follows: deceit takes the form of hiding intentions, the deliberate spreading of misinformation and finally the development of protean strategies based on unpredictable adaptive behaviour to escape from hostile agents or rivalrous conspecifics. Miller (1997) and Grammar et. al. (2002) cite a co-evolutionary arms race in foundational social interactions such as human courtship where deception and proteanism feature. The regions of the brain is associated with ‘mind reading’ or forming beliefs of the intentions of others are the following: the medial prefrontal cortex (MPFC), Dorsolateral Prefrontal Cortex (DLPC) or Paracingulate Frontal Cortex, Rostral Prefrontal Cortex or Brodman Area( BA10), the temporoparietal junction (TPJ), the anterior superior temporal sulci (aSTS) the posterior superior temporal sulcus pSTS and the amygdala. The latter three are meant to be involved in making judgements about trustworthiness. 10 In Tognoli et. al. (2007) the neuro-physiology of the simplest mutual two person direct interaction is studied. They confirm that there is suppression of so called mu rhythm which has been identified as a marker of the activation of the MNS. This is observed irrespective of whether or not coordinated behaviour is needed. In addition they also find a pair of oscillatory components, phi1 and phi2, with the first of these featuring with independent behaviour and the second with coordinated behaviour. 11 There is evidence that autistic individuals have difficulty in passing the so called Sally-Ann test on ascribing false beliefs to others. It has been found that this group has dysfunction in their MNS and ,irrespective of high IQ, they have trouble with mind reading or with making out intentions of others and hence social and strategic skills. 9 9 The field of empirical and experimentally based investigations for the neurophysiological correlates of strategic behaviour, though in its infancy, is burgeoning. Economists, within the subfield of neuroeconomics, are actively contributing to both in the context of individual decision making and in terms of strategic interaction (see, Smith,2002, Mc Cabe et. al. 2000, Rustichini, 2005, 2009, and Cameron et. al., 2005 and Caplin and Dean, 2008). Bhatt and Camerer (2005) give one of the most explicit discussions of how to figure out the other player which is a necessary condition of strategic behaviour : “One way agents might form 2nd-order beliefs is to use general circuitry for forming beliefs, but apply that circuitry as if they were the other player (put themselves in the “other player’s brain”). Another method is self-referential: Think about what they would like to choose, and ask themselves if the other player will guess their choice or not.” Bhatt and Camerer (2005) refer to the figuring out by player 1 of what another player 2 believes that player 1 will do him-self, as 2nd- order self-referential beliefs. They note that such 2nd-order selfreferential mappings feature when intentional deception is involved. Gréze et. al. (2004) conduct experiments aimed at identifying the neural mechanisms in humans that are involved in making judgements about mental states from non-verbal but visual interactions with own and others’ actions. They find that there is activation of the parietal and the pre-motor cortex associated with assessing action prediction role of MNS occurs along with areas that have been associated with so called ‘mind reading’ when judgements of others’ mental states are made. The interesting finding in Gréze et. al. (2004) that is common with the results in Bhatt and Carmerer (2005) is that when there was a mismatch between the player/observer’s prediction for the actions of the other and the actual actions, brain activity is far more widespread and enhanced.12 In contrast, in a ‘prediction equilibrium’, brain activation is much attenuated. Bhatt and Camerer (2005) make an important observation that in a Nash equilibrium when there is a consistent alignment of beliefs between a player’s belief of the other player’s action corresponds to the condition of the brain when prediction equilibrium is observed. Gréze et. al. (2004) conclude that in cases of prediction failure regarding others, individuals must update their own representation of the mental state of the target. In Bhatt et.al. (2010) the conditions of the game 12 Those brain areas that have been observed to be active and remain so when there are violations of ‘prediction error’ are the Temporal Parietal Junction (TPJ), Orbital Frontal Cortex and the neighbouring anterior insula. 10 require players to mutually maintain others in a state of false belief in order to maximize returns in the game. However, in that paper the neuro-physiological conditions for the mental identification of a mutual belief state by a player that the other player ‘knows’ that he intends to lie/mislead has not been investigated. Despite above developments, in contrast to the Baumol/Schumpeter legacy on the role of innovative behaviour in capitalist growth and the large literature in social neuroscience following the provenance of Byrne and Whiten (1988), where the ubiquity of strategic deception and arms race in protean strategies and novel products is well established, this phenomena is missing in the models of Nash equilibria of games studied to date by economists. Bhatt and Camerer (2005) succinctly state this as “in a Nash equilibrium nobody is surprised about what others actually do, or what others believe, because strategies and beliefs are synchronized, presumably due to introspection, communication or learning.” What is missing in this statement is the category of mutual belief and expectation of surprise and the characterization of a Nash equilibrium in which players mutually and logically expect that they will need to surprise and be surprised. Finally, though Arbib (2006) states : “mirror neurons are not restricted to recognition of an innate set of actions but can be recruited to recognize and encode an expanding repertoire of novel actions”, we do not yet have the neurophysiological correlates of novel actions arising in the context of interaction between the self and others. 2.3 Gödel-Turing-Post (GTP) theory of meta-representation, simulation and novelty production So what light can the Gödel-Turing-Post (GTP) theory of computation throw on the above conjectures and hypotheses on what amounts to the simulation theory of mind reading ? The GTP theory now also called recursive function theory, provides the only known axiomatic foundations for meta-representation of an underlying system in terms of encoding using integers (also known as Gödel numbers) to represent the instructions utilizing strings of symbols to achieve encoded outputs from inputs in a finite number of steps in terms of an algorithm or program. Both the encoding of information and the offline execution of the encoded instructions which one can regard as a simulation can be run on ‘mechanisms’ involving any substrata ranging from intra-cellular neuronal biology to silicon chips. This capacity for meta-representation yields the notion of a universal Turing machine 11 (UTM) which can take encoded information of other machines and replicate their behaviour. The combination of operations on encoded information and the finite mechanisms for execution will collectively be called the GTP meta-representational system (MRS). Remarkably, UTMs can run codes involving themselves, which is the basis of self-reference. Self-referential mappings of UTMs involve fixed points of recursive functions. As extensively discussed in Smullyan (1961), in formal systems, a large number of the self-referential computations that can be recursively enumerated relate to provable propositions. The remarkable point is that in a consistent MRS system where two naturally disjoint sets arise from provable and refutable propositions,13 the latter being negations of the former, Gödel (1931) provided the constructive proof that the self-referential computations that cannot be recursively listed, uniquely arise from the operation of negation.14 Hence, the centre piece of Gödel (1931, p.19) is a formal analogue of the Liar15 or hostile agent which led to the proof on the limits of deduction or calculation. The Liar, as the agent or function that falsifies or contravenes, can be formally seen to embody the logic of opposition. This is what gives the GTP framework a natural structure of a two person game with contrarian payoffs. The self-refuting fixed points of contrarian mappings of the Liar ‘produce’, in a manner that will be shown in detail, the famous non-computable fixed points which involve epistemic uncertainty referred to as undecidability. As noted above, while it is not yet clear what neuro-physiological mechanisms are in place for actor-actor interactions involving a mutual belief state on the necessity to propagate false beliefs, the Second Recursion Theorem sets out the conditions needed for fixed 13 If sentences in a formal system are provable and have the status of being theorems (proof being defined as the operation of a Turing machine that halts) then their negations are refutable. Refutable sentences are those that have no proof and hence Turing machines will not halt when attempting their proofs. If a formal system is complete then the set of all sentences denoted as FS satisfies the condition that FS = T U R, where Tand R , respectively, are the set of provable and refutable sentences. FS is said to be incomplete if T U R FS and consistent if T and R are disjoint. The Gödel (1931) incompleteness result and the set theoretic proof of this by Post (1944) provides a constructive proof of a sentence denoted as u such that u FS and u T U R. The sentence u is the ‘witness’ that FS is incomplete. To date, there is only one known way for the construction of such sentences. 14 See, Smullyan (1961) Chapter III , Section 3Theorem 2. 15 Since antiquity, it has been known that self-refuting statements generate paradoxes as in the Cretan Liar proposition : this is false. Gödel’s analogue of the Liar proposition is the undecidable proposition. The latter, denoted as A, has the following structure : A ~ |- (A). That is, A says of itself that it is not provable ( ~ |-). Here ‘~’ is the negation sign and ‘|-‘ signifies proof. However, unlike the Cretan Liar there is no paradox in Gödel’s undecidable proposition as it can be proved that this is so. Any attempt to prove the proposition A results in a contradiction with both A and ~A, its negation, being provable in the system. Simmons (1993, p.29) has noted how with the Cantor diagonal 12 points involving recursive functions. The significance of the MRS is that the agent within whom this is embedded will be able to deduce and encode this non-computable fixed point involving the Liar or the operation of negation. Thus, the first major breakthrough here is how non-computability of certain self-referential mappings instead of being a paradox are theorems in the formal system such that agents with MRS can identify such non-computable fixed points qua undecidable propositions by deduction. Now the question is why is the capacity to make inferences involving the Liar or contrarian is (logically) critical to creative behaviour (see, Markose 2004, 2005) ? Emil Post (1944) developed a set theoretic proof of the Gödel-Turing incompleteness result utilising the notions of creative and productive sets that represent the logic behind the so called productive function which by mapping outside of given disjoint enumerable/listable sets encodes the innovation. The productive set grows by incorporating the encoding for the innovation after it has occurred. Smullyan (1961, Chapter 5) and Cutland (1980) give diagrams that respectively show how Post’s creative and productive sets generate the ‘witness’ for such novel objects and the growth of the productive set manifests an arms race in such novel objects. Remarkably, these are generated from encounters with the Liar or hostile agent. Intuitively, this says expect surprises from the opposition and if innovation is not adopted then expect to be ‘negated’ by the hostile agent, viz. innovate or die. The significance of the mathematical logic of GTP can be summarized as follows: (i)Meta representational systems (MRS) and self referential or reflexive mappings involve computational intelligence of a Universal Turing machine (ii) Contrarian or selfnegating structures like the Liar (as in ‘this is false’) are given recursive analogues in terms of non-computability and these are fully deducible or provable in the MRS as a non-computable state, and (iii) The consequences of (i) and (ii) can be represented by so called creative and productive sets with the latter depicting an arms race in novelty production or 'surprises'. It is Binmore (1987) who first raised the “spectre of Gödel” (ibid) in the context of game theory which attempts to restrict best responses to what can be formally deduced, ie restrict the scope of strategic behaviour to a system that is logically closed and complete. The question that is pertinent here is what of the lemma (which was used to prove that the power set of a set has greater cardinality than a set) we begin 13 hostile agent who will falsify or negate one’s actions if he could deduce what they are? When faced by hostile agents, can one rationally play an action that is known or can be formally deduced, both of which will be called ‘transparent’, or does one innovate and ‘surprise’ the enemy? Following a provenance of complex adaptive systems (CAS) that defines the sine qua non of CAS as its capacity to produce novelty and surprises, Albin (1988) is perhaps the first economist16 to have discussed the necessity for agents to have powers of Turing machines to produce the WolframChomsky Type IV novelty producing structure changing dynamics. As noted by Markose (2005) and Durlauf (2005), almost all mainstream accounts of dynamics in economic interactions eschews this provenance of proteanism with complexity and mostly confines economic dynamics to Type I and Type II dynamical outcomes in the Wolfram-Chomsky schema, viz. limit points and limit cycles. A number of game theory papers such as Anderlini (1990), Anderlini and Sabourian (1995), Canning(1992), Nachbar and Zame (1996), which use recursion function theory confine their analysis to defining the problem of indeterminacy associated with self-refuting decision structures. Indeed, it is interesting to note that these game theory papers discuss neither the significance of nor the possibility for innovation and surprise strategies arranged in a structure of an arms race. The problems here arise for two main reasons. These papers appear not to utilize the major methodological triumph of Gödel (1931) which is the meta analysis that produces fully definable meta propositions, in an ever extendable sequence, in terms of what Post (1944) calls productive functions that map from self-refuting fixed points, that are both true, non-computable and avoids paradox by being verifiably so. Secondly, the characterization of Nash equilibria as fixed points of recursive functions seems not to be specified as such. It was in the seminal paper of Spear (1989) that the Second Recursion Theorem was introduced to formalize the problem of computing rational expectations equilibria as fixed points. Though Spear’s paper is not one that explicitly depicts a game, it will be shown that without the proper formalism of defining fixed points of to have so called “good” uses of self-refuting structures that result in theorems rather than paradoxes. 16 F.A Hayek is the first economist to have discussed the implications for economics that arise from the problems of non-computability that he called the limits of constructive reason and on the possibility that the brain manifests Gödel incompleteness (Hayek, 1952, 1967). Much as it was seminal in the way that Hayek redirected the discussion on the limits of deductive inference from Humean scepticism to the Gödelian logic of incompleteness (Markose, 2004, 2005), Hayeks’s own account of this did not go beyond the Cantor diagonal lemma (see, footnote 15). 14 recursive functions, the Nash equilibria of a game which requires the identification of the meta-representations of mutual best response functions in a two place diagonal alignment, one could be forced into different ‘resolutions’ of the classic problems such as the one between Holmes and Moriarty. Koppl and Rosser (2002) attempt to characterize the Nash equilibrium of the zero sum game that depicts the machinations of Holmes and Moriarty using recursive function theory. They conclude as follows: “We can see that there are best-reply functions, f(x), such that f(x)x for all x. That is, there are best-reply functions without a fixed point. (A fixed point is defined by the condition that f(x)=x.)” . It will be shown that Gödel meta-representational system has no problem ‘referring’ to the fixed point of the best response function that seeks to negate or deceive as in the Holmes-Moriarty game. The important point here, therefore, is not that one or the other player has to find a best response function that does not have a fixed point, but that the fixed point of an important class of best response functions is not computable and this is fully deducible from within the MRS of the players. Thereafter, any total computable function that is a mapping from the non-computable fixed point, which defines the Emil Post production function and which will be called the surprise strategy function can only map outside given recursively enumerable sets. 17 This is so, in order for the MRS to avoid inconsistency. Hence, the aphorism that sufficiently rich formal systems cannot be both consistent and complete. The Emil Post productive function which is a recursive function provides a ‘witness’ (epithet used in Post, 1944) for the incompleteness of the formal system in which such novel objects are produced by a fully mechanized exit route. Finally, in the Wolfram-Chomsky schema on Type IV novelty producing dynamics, the logical necessity to ‘step out’ can only arise in the context of agents with the full powers of Universal Turing Machines. Likewise, consider the Nachbar and Zame (1996) conclusion that “for a large class of discounted repeated games (including the repeated Prisoner's Dilemma) there exist strategies implementable by a Turing machine for which no best response is implementable by a Turing machine” . The implementation of the Gödel incompleteness result shows that that from fully deducible noncomputable fixed points of a game, the only (italics added) strategies that can be implemented by recursive functions, viz. Turing machines, are those that satisfy the property of productive functions producing surprises or innovations that lie outside given recursively enumerable sets. The point here is that Type IV dynamics arise from the logical necessity to ‘step out’ of recursively enumerable sets of the MRS and can be produced only by Universal Turing Machines though such activity cannot be enumerated by them in advance. 17 15 3. Gödel-Turing-Post (GTP) Meta-Mathematics and the Logic of Novelty Production The main purpose of the formal analysis is to show the relevance of the GTP mathematics of incompleteness for the characterization of systems capable of novelty based complex Type IV dynamics. Gödel (1931) pioneered the framework of analysis called meta mathematics pertinent to self-referential structures where he obtains epochal results on the sort of statements an internal observer can make as a meta-theorist if he is constrained to be very precise in what he can know and how he can make inferences. As highlighted by Binmore (1987), the theoretical significance of the analogue of the Gödel type incompleteness or indeterminacy result for formalized game theory stems precisely because this can be proven to arise not from incorrect or inconsistent reasoning or calculation but rather to avoid strategic irrationality and logical contradiction. To this end instrumentally rational players are accorded the full powers of an idealised computation machine in the calculation of Nash equilibrium strategies and all information has to be in a codifiable form. Following from the Church-Turing thesis, the computability constraint on the decision procedures implies that these are computable functions that can only entail finitely specified set of instructions in the computation. Again by a method introduced by Gödel (1931) called Gödel numbering, all objects of a formalisable system describable on the basis of a countable alphabet are put into 1-1 mapping with the set of natural numbers referred to as their Gödel numbers (g.ns, for short). Thus, computable functions can be indexed by the g.n of their finitely encoded program. Impossibility results on computation, therefore, become the only constraints on what rational/optimizing players cannot calculate given the same information on the encoded primitives on the game. 3.1 Some preliminaries on computable functions By the Church-Turing thesis computable functions are number theoretic functions, f : N N where N is the set of all integers.18 Each computable function is identified by the index or g.n of the program that computes it when operating on an input and 18 The first limitative result on functions computable by T.Ms is that at most there can only be a countable number of these with the cardinality of being denoted by 0, while from Cantor we know that the set of all number theoretic functions have cardinality of 2 0. Hence, not all number theoretic functions are computable (see,Cutland,1980 ). 16 producing an output if the function is defined or the calculation terminates at this point. Following a well known notational convention, we state this for a single valued computable function as follows f(x) a(x) =q . (1.a) That is, the value of a computable function f(x) when computed using the program/TM with index a is equal to an integer a(x) = q, if a(x) is defined or halts (denoted as a(x) ) or the function f(x) is undefined (~) when a(x) does not halt (denoted as a(x) ). The domain of the function f(x) denoted by Dom a or Wa is such that, Dom a = Wa ={ x | a(x) : TMa(x) halts}. (1.b) The range of a computable function is defined by the set Ea, Range a = Ea ={ q | a(x) : TMa(x) halts}. (1.b) Definition 1: Computable functions that are defined on the full domain of N are called total computable functions. Partial computable functions are those functions that are defined only on some subset of N. Related to (1.b) is the notion of sets whose members can be enumerated by an algorithm or a TM. Definition 2: A set which is the null set or the domain or the range of a recursive/computable function is a recursively enumerable (r.e) set. Sets that cannot be enumerated by T.Ms are not r.e . The one feature of computation theory that is crucial to game theory where players have to simulate the decision procedure of other players, is the notion of the Universal Turing Machine (UTM). Definition 3: The UTM is a partial computable function, defined as (a,x), which uses the index a of the TM whose behaviour it has to simulate. By what is called the Parameter or Iteration Theorem, there is a total computable function u(a) which determines the index of the UTM such that (a,x) = u(a)(x) a(x) . (2) 17 Equation (2) says that the UTM, on the left-hand side of (2) on input x will halt and output what the TMa on the right-hand side does when the latter halts and otherwise both are undefined. Of particular significance are Turing Machines that use their own code/g.n as inputs in their calculation. We will refer to these as self-referential or diagonal calculations. Definition 4: The set denoted by C is the set of g.ns of all TMs that halt when operating on their own g.ns or alternatively C contains the g.ns of those recursively enumerable sets that contain their own codes (see, Cutland , 1980, p.123, Rogers, 1967, p.62). C = { x | x(x) ) ; TMx(x) halts ; x Wx } (3.a) The complement of C C~ = { x | x(x) ; TMx (x) does not halt; x Wx} (3.b). Theorem 1: The set C~ is not recursively enumerable. In the proof that C~ is not recursively enumerable, viz there is no computable function that will enumerate it, Cantor’s diagonalization method is used. 19 3.2 Post (1944) set theoretic characterization of Gödel Incompleteness As indicated in Section 2, we will now state the formal character of systems capable of the endogenous production of novelty or surprises in terms of the notion of creative and productive sets first defined by Emil Post (1944). Definition 5: A creative set Q is a recursively enumerable set whose compliment, Q~, is a productive set. The set Q~ is productive if there exists a recursively enumerable set Wx disjoint from Q (viz. Wx Q~) and there is a total computable function f !(x) which belongs to Q~ - Wx. f !(x) Q~ – Wx is referred to as the productive function and is a ‘witness’ to the fact that Q~ is not recursively enumerable. Any effective enumeration of Q~ will fail to list f !(x), Cutland (1980, p. 134-136). Assume that there is a computable function f = y , whose domain Wy = C~ . Now, if y Wy , then y C~ as we have assumed C~ = Wy . But by the definition of C~ in (3.b) if y Wy , then y C and not to C~ . Alternatively, if yWy , y C~ , given the assumption that C~ = Wy . Then, again we have a contradiction, as since from (3.b) when yWy , yC~ . Thus, we have to reject the assumption that for some computable function f = y , its domain Wy= C~ . 19 18 Lemma 1: Set C in (3.a) is a simple example of a creative set. The productive function f(i)= 1 is the identity function for set C. By the definition of C if any number i C i Wi by the definition of C. Hence, for f(i)= 1 if f(i) C i Wi . If Wi is disjoint from C, then f(i) C Wi.. If i Wi , then i C and Wi will not be disjoint from C. For any generic r.e set Q and the productive function f(i) which is not an identity function that we have by Lemma 1 for set C in (3.a), we need some ‘reduction’ of set C to Q. Lemma 2 below is analogous to Proposition 2 in Smullyan (1961, p 96, Chapter IV). Lemma 2: Let the recursive function f(i) define the following reduction of set C to Q f: i C then f(i) Q. Hence, C =f -1 (Q). Let Wi¬ be disjoint to Q . Then there is a recursive function t(.) s.t it is the index of set, Wt(i`) = f -1(Wi¬ ) , viz Wt(i`) C~ . Hence, Wt(i`) C~ , t(i`) is the productive function of C with t(i¬) C Wt(i`) . Likewise, f (t(i¬)) is the productive function for Q~ and f (t(i¬)) Q Wi¬ . The notation f!(x) for the productive function given in Definition (5) will be justified as it will shown that f!(x) the productive function which implements the proof of the incompleteness of the formal system also corresponds to the best response surprise strategy function in the Nash equilibrium of a game that produces the innovation based structure changing Type IV undecidable dynamics. The set Q is reducible to the prototypical creative set C in equation (3.a) which contains self-referential calculations that converge. They will be shown to correspond to computable fixed points and equivalent to provable theorems in a formal system. The creative set on which Turing Machines halt is associated with Type 1 and Type II dynamics which can be called (computable) order associated with limit points and limit cycles. In a formal system all negations of theorems in the system can be listed as being refutable and hence we have a recursively enumerable subset Wx of C~ in the domain on which Turing machines do not halt. Such mappings represent Type III deterministic chaotic dynamics. In the context of a game, the noncomputable fixed involving the Liar strategy when there is 2nd order self-referential recognition that the other player has wised up to the deceit or negation qua Liar, should correspond to this chaotic mapping. 19 Figure 1 Post (1944) Set Theoretic Representation of Gödel Incompleteness in the Domain Outside Disjoint Recursively Enumerable Sets (See Definition 5) diuu Type I and Type II Dynamics (Limit Points Or Homogeneity and Limit Cycles) Type IV Novelty based structure changing undecidable dynamics Type III Chaotic Dynamics Recursive Enumerable subset Wx on which TMs which TMs can halt be deduced not to halt Remarkably, Korn and Faure (2003) who investigate the role of chaotic Creative Set C on Productive set C~ on which TMs do not halt dynamics in the neuro-physiology of the brain, review the work of Freeman and collaborators (Skarda and Freeman, 1987) and conclude that “chaos confers the (neural) system with a deterministic ‘I don’t know state’ from within which new activity patterns can emerge… chaotic states… are well designed for preventing convergence and for easy ‘destabilization’ of their activity by a novel input .. . they are ideally fit for accommodating the neural networks with a new and still unlearned stimulus”. Precisely on cue, it is indeed from this self-negating non-computable fixed point where calculations cannot converge that the recursive productive function f !(x) maps outside the equivalent reductions (using Lemma 2 above) of the r.e disjoint sets C and Wx. Hence, the domain for novelty producing Type IV dynamics in the proposed game lies outside such recursively enumerable disjoint sets. 20 3.3 Meta-representational System (MTS) and a simulation theory for a two person game This section sets out how a MTS organizes encoded information involving self and other. This interactive situation is best characterized by a two person game. The primitives of the game, best interpreted as one in which both cooperation and opposition arise such as in a regulatory/policy game or a parasite-host game, is codified as follows. G= {(p,g), (Ap, Ag), sS}. Here,(p,g) denote the respective g.ns of the objective functions, to be specified, of players, p, the private sector/regulatee and g, government/regulator. The action sets denoted by Ai are finite and countable with ail i , i (g, p) being the g.n of an action of player i and l=0,1,2,.....,L. An element sS denotes a finite vector of state variables and other archival information and S is a finite and countable set. The action set A = A1 U A1 represents the known technologies. In order to highlight the fundamental recursive nature of actions as technologies and the potential for new technologies, the class of best response strategy functions will be defined as a set of total computable functions. Definition 6: The best response strategy functions fi, i (p,g) that are total computable functions can belong to one of the following classes – f i1 1( Identity Function) fi = fi Rule Abiding Rule Breaking / Liar ! Surprise fi (4.a) such that the g.ns of fi are contained in set , = { m | fi = m ,m is total computable}. (4.b) The set which is the set of all total computable functions is not recursively enumerable. The proof of this is standard, see, Cutland (1980). The total computability of best response functions fi = m, m in (4.a,b) yields the notion of constructible/effective action rules such that a finitely codifiable description of some (institutional) procedure which is defined for all mutually exclusive states of the world is obtained. As will be clear, (4.b) draws attention to issues on how innovative actions/institutions can be constructed from existing action 21 sets. The remarkable nature of the set is that potentially there is an uncountable infinite number of ways in which ‘new’ institutions can be constructed from extant action set A. The task is to show the conditions under which it is mutually deducible that the best response function fi, i (p,g) satisfies Post’s productive function and is a surprise strategy, fi = fi!= m , such that m -A. Only such innovations will be accorded with the status of strategic innovations. A major implication of imposing computability constraints on all aspects of the game is that all meta-information with regard to the outcomes of the game for any given set of state variables, s S, can be effectively organized by the so called prediction function (x,y) (s) in an infinite matrix of the enumeration of all partial computable functions. This is given in Figure 2 (see, Cutland, 1980, p.208). The tuple (x,y ) identifies the row and column of this matrix whose rows are denoted as j, i= 0,1,2,...... . Figure 2 : Meta –Information on Outcomes of Decision Problem for a 2-person Games 0 (0,0) (0,y) 1 (1,0) (1,y) 2 (2,0) (2,y) . x (x,0) (x,1) (x,2) (x,3) (x,x) (5). . The function (x,y) (s) if defined at a given state s and (x,y) yields (x,y) (s) = q . Here, q in some code, determines the outcome of the decision problem of the game and q E x . Note, (x,y) is the index of the program for this function that produces the output of the strategic decision problem of the 2-person game. The tuple also identifies a point on the matrix in Figure 2. The conditions under which the output of the prediction function for each (x,y) point in the above matrix is defined is given in the following Theorem. 22 Theorem 2: The representational system is a 1-1 mapping between meta information in matrix in Figure 2 and executable calculations such that the conditions under which the prediction function which determines the output of the game for each (x,y) point is defined are as follows: ( x ,y ) ( s) x ( y) (s) q , iff x ( y) . (6) Here, the total computable function (x,y) modelled along the lines of Gödel’s substitution function20 (see, Rogers, 1967,p.202-204) has the feature that it names or ‘signifies’ in the meta system the points in the game that correspond to the different executed calculations on the right-hand-side of (6) as we substitute different values for (x,y) for a given state s. The g.ns representing (x,y) can always be obtained whether or not the partial recursive function x ( y ) on the right-hand side of (6) which executes internal programs halts or not. Proof : See Rogers (1967). By the necessary condition in (6) if the function x (y) on the right-hand side (RHS) executing the internal calculation is defined, we say the prediction function (x,y) in the meta system on the left-hand side producing the output of the game is computable and the outcome q of the game at that point is predictable. Likewise, the ‘only if ’ condition in (6) implies that meta statements that are valid on the predictability of the outcomes of the game at any (x,y) must give the correct inference on whether program executions on the right-hand side terminate. Definition 6: The two place notation of the meta-system (x,y) can be used to define two second-order self-referential encodings of the following kind: (a) When player i has to determine her own best response function, the first place entry x in (x,y) refers to what the player i does (viz the g.n of best response function fi) given that player j plays a strategy that is consistent with player i’s belief denoted by y of what player j believes player i has done.21 (b) When player j determines the best response of the other player i then the first place entry x in (x,y) refers to j’s simulation of what i does (viz the g.n of best 20 This approach economizes on formalism and enables us to high light and exploit the Fixed Point Theorems of recursive function theory to determine Nash equilibrium outcomes more readily than has been the case in for instance in Anderlini(1991),Canning(1992) and Albin(1982). 21 Note this is what has been referred to as self-referential 2nd order beliefs in Bhatt and Carmerer (2005). 23 response function fi ) and the second place y denotes j’s belief of what i’s believes regarding j’s simulation of i. (c) All Nash equilibria and other relevant fixed points of the game satisfying what has been referred to as consistent alignment of beliefs (CAB, for short, Osborne and Rubinstein,1994) have to be elements, (x,x), along the diagonal array of this matrix. Note, (x,y) which are off diagonal entries in matrix violate the CAB condition. The set up in (6) formalizes the relationship between a mirror/meta system on the LHS of (6) which records all ‘successful’ machine executions on the RHS of (6). The latter relates to the canonical system involving online activity. The case (b) in Definition (6) given in the form (x,x) can be seen as an example when a trigger such as direct observation of the action of another occurs and ‘fires’ up off line simulation in the meta system of j’s prediction of i’s action with the full prediction of the two person interaction following automatically with great economy from past recorded points such as (x,x). GTP meta-analyses are operations on Godel numbers and bypass the online calculations involved. In other words, all permissible inferences are obtained in short hand from encoded information. Likewise, on account of the ‘only if’ condition in Theorem 2, many interesting aspects of the Nash equilibria of computable games can be established only with reference to the meta analyses and information in the matrix with no explicit reference to physical executions of programs such as the optimization algorithm, to be discussed, being made by the players. Two out- of-equilibrium belief states will be defined. The case when player i simply attributes a different belief to player j of i’s own action x is denoted by (x,y). The case when player i deliberately acts in such a way he believes player j is in a state of false belief about i will be typically denoted as follows. Definition 7 Deliberate Deceit and False Belief: Denoting by x¬ the negation of x brought about by best response function fi¬ defined in (4.a), we have (x¬ ,x) in the two place meta representation of the game by i. This is the case when player i knows that he has negated action with g.n x and believes that player j believes that he, viz. player i, is playing x. Both logically and nuero-physiologically as noted in the introduction, this out-of-equilibrium situation involving false beliefs has great significance. 24 It will be shown how total computable functions for the best response function fi , i=p, g in a 2 person game when applied to the diagonal array of the matrix can dynamically move it to a specific row in matrix . The Fixed Point or Second Recursion Theorem states that there exists an index n of a program/set of instructions that computes f(n) and then applies f(n) so that both n and f(n) are instructions for the computation of the same recursive function and if the latter is computable at this point the same outcome q is predicted by the operation of the two programs. Theorem 3: Fixed Point or Second Recursion Theorem (Cutland, 1980 p. 200) Let f be a total unary computable function then there exists a number n such that such that f (n) = n. (7) Note, f(n) n being codes for different programs, but they identify the same function and both sides of equation will yield an identical output if f has a computable fixed point. The proof that any computable function f has a fixed point follows from the fact that a function representing an encoded set of instructions when applied to the diagonal array of matrix belongs to some row of the matrix say v, such that the v+1th element in the vth row ,f((v,v)) , and the v+1th element in the diagonal array of coincide, yielding f((v,v))= (v,v). (8) Thus, the vth row of matrix satisfies: vf((0,0)) f((1,1)) f((2,2)) f((3,3)).... f((v,v))= (v,v) …. f((x,x)).. . A major advantage of this framework is that the determination of Nash equilibrium strategies involves the use of total computable best response functions (fp , fg) which can be shown to operate directly on points such as (x,x) to effect computable transformations of the system from one row to another of matrix with special reference to its diagonal array, see, Figure 2. Theorem 3 is used in the determination of the fixed points for the total computable functions best response function fi , i=p,g. When one player applies his best response fi , the condition that 25 both players identify the same prediction function as producing the output of the game at that point is called a rational expectations. fi ( v , v ) (s) = ( v , v ) (s) , i (p,g). (9) How player j≠i, identifies v,v) as the fixed point of i’s best response function fi will be derived in the next section 4. Nash Equilibria : When Does One Surprise the Opposition ? 4.1 Total computable best response functions and optimal strategy functions The optimization algorithms entailed in achieving best responses in the game arise from the objective functions of players. Definition 8 : The objective functions of players are computable functions i , i (p,g) defined over the partial recursive payoff/outcome functions specified as in (4). Arg max i ( bi , bi / j ) (s) , bi Bi i (p,g) The choice set Bi contains the g.ns of strategy functions. The Nash equilibrium strategies (gE , pE ) with g.ns denoted by (bpE, bgE) entail up to two subroutines or iterations, to be specified below. In principle, the strategy functions (g , p ) are Universal Turing Machines that simulate optimal strategies of the players that satisfy (10) and involve the total computable best response functions (fp , fg) which incorporate elements from the respective action sets A= (Ap ,Ag) and given mutual 2nd order self-referential beliefs of one another’s optimal strategy. Note, ail , l= 1,2,… L, denote the elements of the sets Ai, i=p,g. In the two place notation given in (6), bi is the g.n of i’s optimal strategy given that i’s belief that j has optimally chosen its strategy on the basis of j’s belief, bi/j , of i’s strategy . Note that we will use g.ns zi, i (p,g) to represent encoding of the optimization calculus with respect to respective objective functions. In the Nash equilibrium best response calculus, the first subroutine denoted by g.n b1 simulates the other player’s optimization calculus to determine optimal action. The problem is that actions can in general be implemented by any total computable best response function, fi = m , m , i (p,g) in (4.b). In standard rational choice models of game theory, the optimization calculus in the choice of best response restricts choice to given actions sets. Hence, starting 26 from some point x,x), the strategy functions map from a relevant tuple that encodes meta information of the game into given action sets i ( fix,x), z, s, A) Ai and fi= m , mA, i (p,g) . (11.a) Unless this is the case, as the set is not recursively enumerable there is in general no computable decision procedure that enables a player to determine the other player’s best response functions. However, in principle, a strategic decision procedure (g , p ) for choice of best response, fi= m , m , i (p,g), can map into -A , implying that an innovative action not previously in given action sets is used. i (fi(x,x)), z, s, A) - A and fi = fi ! = m , m -A, i (p,g). (11.b) The question is which fixed point (x,x), fully deducible in the meta-mathematics, will trigger such Nash equilibrium surprise strategies, (gE! , pE! ), with g.ns denoted by (bpE!, bgE!) ? It has been noted in passing by Anderlini and Sabourian (1995, p.1351), based on the work of Holland (1975), that heterogeneity in forms does not arise primarily by random mutation but by algorithmic recombinations that operate on existing patterns. However, a number of preconceptions from traditional game theory such as the ‘givenness’ of actions sets prevent Anderlini and Sabourian(1995) from positing that players who as in (11.b), equipped with the wherewithal for algorithmic recombinations of existing actions, do indeed innovate from strategic necessity rather than by random mutation. Indeed, it is the very function of the Gödel meta framework to ensure that no move in the game made by rational and calculating players can entail an unpredictable/surprise response function from set - A unless players can mutually infer by strictly codifiable deductive means from (x,x) that (11.b) is a logical implication of the optimal strategy at the point in the game. In other words, the necessity of an innovative/surprise strategy as a best response and that an algorithmic decision procedure is impossible at this point are fully codifiable propositions in the meta analysis of the game. While it will be shown what specific structure of opposition logically and strategically necessitates surprise strategies in the Nash equilibrium of the game, in keeping with the set theoretic formulation of novelty 27 production in Figure 1, the corresponding creative and productive disjoint subsets of the strategy sets have also to be developed. 4.2 Fixed Point/Second Recursion Theorem: The base-point The meta analysis in the determination of Nash equilibrium strategies (pE , gE) with g.ns (bpE, bgE ) will be undertaken here. In the classic matching pennies game format, the optimal outcomes for the government/regulator arise when the regulatee/private sector is rule abiding or coordinating. Calculations start at this so called base-point which is the fixed point of fg which has to be arrived at by player p on the RHS on (12) : f g ( ba , ba ) (s) = ( b , b ) (s) q a a . (12) Here, ba is the g.n of the strategy fg that selects the optimal action a from set A in (11.a) when g is put in for the index i. In the two place notation in ( ba ba ) on the RHS of (12), the first ba is the code of the program from (11.a) as adopted by p to simulate the optimal policy rule a and the second place ba denotes that p believes that g believes and acts on the basis that the p is rule abiding and has left the policy rule a unchanged. The prediction functions in (12) ba ,ba ) s is computable and outcomes of the policy rule a is predictable and q is the desired outcome that g wants in state variables when applying this policy rule a . It is convenient to assume that policy rule a is optimal for g if the private sector is rule abiding. By rule abiding is meant that p will leave the system unchanged in terms of the row ba of matrix . 4.2 The Liar/Rule Breaker Strategy :The logic of opposition For player p, for the given (a,s) it may be optimal for p to apply the Liar strategy, fp¬ ( ba , ba ), with code ba¬ . Formally, the Liar strategy has the following generic structure. For any state s when the rule a applies, f p ( ba ,ba ) (s) q ~ q~ E b a ( ba ,ba ) (s) q q E b a .(13.a) For all s when policy rule a does not apply, fp¬ = 0 : Do Nothing . (13.b) 28 The Liar can successfully subvert with certainty in (13.a) if and only if () the policy rule a has predictable outcomes (LHS of (13.a)) and fp¬ itself is total computable. Thus, fp¬ = m , mp, must include a codified description of an action rule if undertaken by the Liar can subvert the predictable outcomes of the policy rule a. Formally, if q is predicted then the application of fp¬ to ( ba , ba ) is equivalent to the condition of deliberate deceit in Definition 7 and the g.n of this strategy is ( ba¬, ba ). That is, p has negated ba and he knows that g harbours a false belief about him, that p is rule abiding with ba. This out- of- equilibrium ( ba¬, ba ) point in the game is off diagonal in terms of the matrix andwill bring about an outcome q ~ E b which belongs to a set disjoint from the set that contains the desired output of a rule a for all s for which rule a applies, viz. E b E b E b he outcomes (q~ a ,q a a ) can be zero sum but in general we refer to property q~ E b in (13.a) as being a oppositional or subversive. Thus, we come to the point as to why agents who precipitate the WolframChomsky Type IV dynamics with innovation have to have powers of self-referential calculation. Firstly, g acknowledges the identity of the Liar in (13.a) and understands that transparent rule a cannot be implemented rationally as the outcome now defined by ( b , b ) (s) = q~ is the opposite of what is optimal for g. Player g has to identify a a the fixed point of fp which is formally given as (ba , ba ) on the RHS of (14) ¬ ¬ ¬ where ba¬ is the code for the Liar strategy in (13.a). Likewise, both g and p in their respective second place entry (ba¬ , ba¬ ) on te RHS and LHS of equation (14) remove any attribution of false belief to the other. Thus, the Liar, p, knows that g knows that p is the Liar on the LHS of (14) and likewise, g knows that p knows that g has identified him. Theorem 4: The prediction function indexed by the fixed point of the Liar/rule breaker best response function fp¬ in (14) is not computable and corresponds to the famous Gödel non-computable fixed point. f ( b ,b ) (s) ( b , b ) (s). p a a a a (14) 29 The proof is standard. Assume it is computable and the R.H.S of (14) produces the output q~ and the L.H.S by the definition of the Liar strategy produces output q. Hence, if (14) is computable then we have q=q~ which is a contradiction. Though the conditions of the out-of-equilibrium success of the Liar are spelt out in (13.a , 13.b), in many fast moving co-evolutionary systems, predictable strategies such as ba or ba¬ may not be observed, and instead only the arms race in novelty given in the next section is what persists such that both players survive. On the other hand, in environments suitable for neuro-physiological experiments of such a game, it is interesting to identify the juncture at which a player p knows his best payoffs come from the out-of- equilibrium configuration wherein the other player g has to kept in a state of false belief ( ba¬, ba ) given in Definition 7. 4.3 Surprise Nash Equilibria There is no paradox in stating that as both players can prove the noncomputability of (14) they will be able to mutually deduce that that the only Nash equilibrium strategies for both players that is consistent with meta information in the fixed point in (14), is one that involves strategies that elude prediction from within the system. On substituting the fixed point (ba¬ , ba¬ ) in (14) for (x,x) in (11.b), g’s Nash equilibrium strategy gE with g.n bgE implemented by an appropriate total computable function such as (12.a) must be such that gE (fg (ba¬ , ba¬ ), z, s, A) - A and fg = fgE! = m , m -A. (15.a) That is, fg! implements an innovation and bgE ! is the g.n of the surprise strategy function in (14.a) hence (bgE !, bgE !) is the fixed point of fg !. Likewise, for player p, fp! implements an innovation in (15.b) and bpE ! is the g.n of the surprise strategy function viz. (bpE !, bpE !) the fixed point of fpE!. Thus, pE (fp ( ba¬, ba¬ ), z, s, A) - A and fp = fp E! = m , m -A. (15.b) 30 The intuition here is that from the non-computable fixed point with the Liar, the total computable best response function implementing the Nash equilibrium strategies can only map as above into domains of the action and strategy sets of the players that cannot be algorithmically enumerated in advance. Using Theorem 4, Definition 5 and Lemma 2, we will now prove the incompleteness results for the strategy sets of the players from the Liar/rule breaking strategy. Analysis will be done for p’s strategy set Bp as the strategy functions fp and fg, respectively, can be shown to implement a reduction, as in Lemma 2, of the prototypical creative set C in ( 3.a). Corresponding to those (agl , s) tuples, agl Ag of g’s base point optimal strategy for which p’s best response fp is to be rule abiding viz. fp =1, the g.ns of these optimal strategies for p, bp 1 Bp result in computable fixed points . Here b1 indicates the subroutine 1 in the determination of the Nash equilibrium strategy. This set denoted by ßp+ can be generated by eductive/recursive methodology entailed in the proof of Theorem 3. Thus, ßp+ = { b p |b p 1 (b p ) for all (agl , s), agl Ag , fp =1 }. (16.a) 1 1 Using logic in (13.a,b), a set ßp¬ can be recursively be generated that contains the g.ns of p’s strategies for when it is optimal for p to use the Liar best response function fp¬ to those (agl , s) tuples, agl Ag of g’s action set. By Theorem 4, this is a set of p’s strategies that can be proven to result in non-computable fixed points. Hence, ßp¬ = { b p |b p 1 (b p ) for all (agl , s), agl Ag , fp = fp¬ }. 1 1 (16.b) For the same (agl , s) tuple, agl Ag constituting g’s base point optimal strategy, p’s optimal strategy bp* cannot belong to both ßp+ and ßp¬ . Thus, logical consistency of the meta analyis requires ßp+ ßp¬ = and these are disjoint sets. Now, define the compliment set of ßp+ denoted by ßp+c as ßp+c = { x | x (x) , x Bp }. (17) 31 As ßp+ ßp¬ = , the two sets are recursively enumerable disjoint sets with ßp¬ ßp+c by definition in (16.b). Hence, the incompleteness of p’s strategy set Bp that arises from the agency of the Liar strategy requires the proof that ßp+c is productive as in Definition 5 with the g.n of the surprise strategy bpE !=b2(fp , bpE ! ßp+c - ßp¬. FIGURE 3 The Incompleteness of p’s Strategy Set Bp bpE ! = b2 ( fp ( ba¬,ba¬ ) ) :SURPRISE STRATEGY bpE ! = b2 ( fp ( ba ,ba ) ) ¬ ßp+ ¬ W ! n ßp+c ßp+c is defined in (17) Theorem 5: The g.n of player p’s Nash equilibrium surprise strategy is defined as bpE ! = b2 ( fp ( ba¬,ba¬ ) ) from (12.b) having substituted in ( ba ¬ , ba ¬ ) from the non-computable fixed point in (16). Then, by construction bpE ! is a ‘witness’ for the productivity of the set ßp+c such that bpE ! ßp+c –b2( ßp¬ ) and p’s optimal strategy set Bp is incomplete . (i) As bpE ! is the g.n of the total computable best response function fp! implementing the surprise or the innovation in the system as defined in (15.b), fp! is the productive function for the set ßp+c. This is shown in Figure 3. (ii) Once the surprise Nash equilibrium strategy has been implemented by p which has g.n b2 (fp ( n¬)), the growth of the strategy set can be proven to take the following form: W ! n 1 = W 1 { b2 (fp ( n¬)) } n 32 This is shown in Figure 4. Proof: See Appendix. FIGURE 4 Arms Race in Surprises/Innovations: Growth of the Productive Strategy Set Bp+c bpbE0!! , b1! …. bn-1! g.n (fp(σn¬)= bn! W σn ! W σn+1! g.n: Godel Number The significance of Theorem 5 is that the surprise strategy is fully definable as a meta–proposition and is paradox free as the surprise strategy is indeed a pure innovation in the strategy set Bp and outside of sets ßp+ ßp¬ that can be enumerated by eductive calculation and information in G, see Figure 3. It is precisely the absence of logical inconsistency and strategic irrationality in the meta proposition on the surprise strategy that sustains the consistent alignment of beliefs condition of a Nash equilibrium with surprises. Thus, as already observed, for human players utilizing ideal reasoning provided by Gödel meta analysis, the set of best response functions in (6.b) should provide an inexhaustible source of surprise or innovative strategies. However, by the same token, by Theorem 5, there is no algorithmic way by which the prediction function with the index ( bpE!, bpE!) at the surprise equilibrium can produce an output q though both players can mutually identify that ( bpE!, bpE!) is the fixed point of the surprise Nash equilibrium best 33 response function fpE. Indeed, ( bpE!, bpE!) says that this is so self-referentially. In a nutshell ‘innovate or die’ describes this Nash equilibrium in which neither party can unilaterally deviate without drastically impairing their prospects. Theorem 5 and Figure 3 on the surprise strategy in a Nash equilibrium of a game formally corresponds to the set theoretic proof of Gödel’s undecidable proposition in miniature, Cutland (1980). We have succeeded in showing the formal equivalence between the Nash equilibrium with surprise or novelty in Figure 3 and the phase transition in dynamical systems theory that characterizes the endogenous production of novelty as in Figure 1. Following from part (ii) of Theorem 5 and as seen in Figure 4, once players are locked in an oppositional structure, the strategy set of each player will grow utilizing the formalism of an arms race in novelty. 5. Conclusion This paper has brought together the logical, neurophysiological and social neuroscience literature to throw light on strategic protean behaviour. Based on extensive studies, the picture that Baumol (2002) paints of technology races in capitalism is not of isolated individuals making random discoveries, but of a concerted and institutionalized strategy of innovation to stay ahead of the technology race. Following the legacy of Driver and Humpheries (1988) and Bryne and Whiten (1988), social proteanism is hypothesized to be the consequence of predictability which can be punished by agents capable of prediction. The cognitive basis of the recurring pursuit-evasion type contests that entail arms-races in new behaviours that are diverse as they are spectacular, is still not fully understood. It is only in the meta-mathematics of Gödel that negation of what is predictable by agents plays a central role in the production of novel objects in the system to bear ‘witness’ to the incompleteness of the system. The self-negating diagonal or self-referential Gödel sentences in their productive function variant, often regarded as dubious and artificial mathematical constructs, are shown to be Nash equilibrium fixed points of the best response functions of a ubiquitous game where players are locked in a hostile structure. Indeed, despite the invention of the epithets ‘creative’ and ‘productive’ sets by Emil Post(1944) to underscore these characteristics of the logical procedures involved in Gödel incomplete systems, almost no mention or use of such constructs have been made to date even by game theorists who have 34 used recursive function theory in the context of strategic behaviour. Albin (1998) and Markose ( 2004,2005) are the only exceptions here as they draw on a provenance of complexity adaptive systems Wolfram-Chomsky schema (see, Casti and Wolfram,1984) to highlight the role of agents with powers of universal Turing Machines to generate Type IV novelty producing structure changing dynamics. The ingredients of the Gödel meta-representational system (MRS) as set out in Theorem 2 and equation (6) capable of offline operations on encoded information which while related to the physical execution of same, has been shown to be the basis of powerful meta-analysis. The parallels between canonical and mirror neurons and the Gödel MRS have been noted. Just as undecidability and incompleteness are theorems rather than paradoxes in a rich enough meta-representational system (MRS), in this theory, players with the specified MRS will infer the logical necessity to mutually surprise. It still remains to be seen if the human mirror neuron system has the capacity for meta-analysis that extends to the 2nd order self-referential recursions that are needed for deceit. Tognoli et. al. (2007) have made some advances in the experimental procedure to detect the mirror neuron activity in a mutual two person direct interactive setting. The mutual recognition of hostility, negation or deceit - places the metarepresentational system of agents in a state of chaos corresponding to non-converging calculations neuronal mappings. Such implications for novelty recognition and production have been cited in Korn and Faure (2003). The GTP theory says that the only recursive mappings from such fixed points involving the logical persona of the Liar are those that map out side of recursively enumerable sets. This in layman’s terms corresponds to thinking ‘outside the box’. The deeply contextual points of exit and innovation which follow in lock step have to be noted. The exit routes are guided by the encoded information on specific hostile interactions. Thus spelling out of the logical foundations of novelty production in a strategic setting suggests many rich investigative lines for empirical neuro-physiological experiments. The urgency for these lines of investigation arises from the fact that extant mathematical models of strategic behaviour cannot account for protean behaviour which is ubiquitous in socio-economic systems. 35 APPENDIX PROOF OF THEOREM 5: The proof entails showing that the best response function fp in (17.b) is the productive function denoted as fp! with the ‘!’ intended to focus on the feature that an innovation outside given action sets is involved, viz. fp! = m , m -A. We will use the two following Lemmas in the proof as well as the property of the set ßp+c given in (17) and recall that b1 and b2 are the indexes of the first and second subroutines of the program for the determination of Nash equilibrium strategies.. Part (i): Consider fpE , the best response function for player p, at the second subroutine denoted by b2 of the Nash equilibrium strategy, to be the recursive reduction function in Lemma 2. Here with no loss of generality, let b1n¬ ( ba¬ , ba¬) (A.1) signify the non-computable fixed point from p’s Liar/rule breaking strategy in (14) and Theorem 4 and b1 indicates the index of the first subroutine of the Nash equilibrium. Consider W ! to be the recursively enumerable subset W ! n n ßp+c in Lemma 2. Then as fp E is the reduction of the prototypical creative set C such that there exists an index , here b1, which yields Wb1 n = fpE-1 ( W n! ). Note Wb1 = n ßp¬ and ßp¬ is defined in (16.a) . It then follows from Lemma 2 that fpE( b1n¬ ) is the productive function for the set W ! n implementing the surprise Nash equilibrium and b2 ( fp ( ba¬,ba¬ ) )= bpE ! is the Gödel number for it. Part (ii) : Generically, let any Wx ,Wx ßp+c of be constructed as W ! of Part (i) to n yield a non-repeating, recursive enumeration of surprise strategies thereof with !n(.) denoting this total computable enumerating function such that and, W In other words W ! n ! n 1 = W 1 { b2 (fp ( n¬)) } . 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