Paavo Pylkkänen Dept Philosophy & The Academy of Finland CoE in the Philosophy of the Social Sciences (TINT), Univ Helsinki, Finland Dept Cognitive Neuroscience & Philosophy, Univ Skövde, Sweden paavo.pylkkanen@helsinki.fi ¡ Consciousness has during recent decades become the target of interdisciplinary empirical research -> birth of a new subject / field of research, consciousness studies ¡ It seems obvious that conscious experience is a property of the brain ¡ But: we seem to have no conception about how objective and mechanically functioning neural process could produce our subjective and qualitative experiences (Nagel, Chalmers). § Note though that there is no agreement about whether the hard problem is genuinely hard or whether it is a pseudo-problem! § The phenomenon / problem does not exist (eliminativism, ”dissolution strategy”) § Reducible to neural processes § Non-reducible, non-physical entity (substance dualism) § Irreducible aspect of reality ([double]-aspect monism) § Non-reducible, non-physical property (non-reductive materialism) § Non-reducible, physical property (emergent materialism) § Strongly linked to fundamental theories in physics (e.g. quantum theory) § We will never be able to understand it (New Mysterianism) ¡ Multiple drafts theory (Dennett) ¡ Sensorimotor theory (O’Regan and Noë) ¡ Biological naturalism (Searle, Revonsuo) ¡ Naturalistic dualism (Chalmers) ¡ Higher order theories (HOTs) of consciousness ¡ Externalist representationalism (Tye, Dretske) ¡ Neurophenomenology (Varela, Lutz, Thompson, Noë) ¡ Reflexive monism (Velmans) ¡ Virtual reality / world simulation theory (Metzinger, Lehar, Revonsuo) ¡ Global workspace theory (Baars) ¡ Neurobiological theory (Crick and Koch) ¡ The dynamic core (Tononi and Edelman) and the information integration theory (Tononi) ¡ Thalamocortical binding theory (Llinas) ¡ Recurrent processing theory (Lamme) ¡ Microconsciousness theory (Zeki) ¡ Consciousness as the feeling of what happens (Damasio) ¡ Consciousness as orchestrated quantum collapse in neural microtubules (Hameroff and Penrose) ¡ Can the concept of information help us to develop a satisfactory theory of consciousness? § Chalmers’ double-aspect theory of consciousness § Tononi’s integrated information theory of c ¡ Dretske’s [1981] and Barwise and Seligman’s [1997] attempts to ground information, understood as factual semantic contents, on environmental information [“naturalization of information”] ¡ Also: Bohm’s mind-matter scheme, based on quantum theoretical active information (“the pilot wave”) Floridi, Luciano, "Semantic Conceptions of Information”, The Stanford Encyclopedia of Philosophy ¡ promises to offer a principled account of § what experience is and § what type of physical systems can have it ¡ Starts by identifying the essential properties of consciousness ¡ Then asks what kinds of physical mechanisms could possibly account for them. -> a mathematical theory of consciousness Not restricted to neural explanations! ¡ phenomenological axioms ¡ ontological postulates ¡ identities ¡ EXISTENCE: consciousness is an undeniable aspect of reality ¡ COMPOSITION: each experience consists of multiple aspects ¡ INFORMATION: each experience differs in its particular way from others ¡ INTEGRATION: each experience is (strongly) irreducible to non-interdependent components ¡ EXCLUSION: each experience excludes all others ¡ To parallel the phenomenological axioms, IIT posits a set of postulates. ¡ These list the properties physical systems must satisfy in order to generate experience. ¡ We need to account for the existence of consciousness (from its own intrinsic perspective) ¡ Postulate: there has to be a system of mechanisms with a cause-effect power upon itself § i.e. intrinsically, independent of extrinsic causes and effects. (e.g. dreams) ¡ We need to account for the compositional structure of consciousness § i.e. that each experience is composed of many phenomenological distinctions. ¡ Postulate: it must be possible to compose elementary mechanisms into higher-order mechanisms which have irreducible causes and effects. ¡ We need account for the fact that consciousness is differentiated § i.e. that each experience has a specific set of phenomenological distinctions ¡ Postulate: a system of mechanisms must specify a differentiated conceptual structure via a process of in-forming ¡ A concept is how each mechanism within the system specifies the probability of past- future states of the system (cause-effect repertoire). § A conceptual structure then is the set of concepts specified by the mechanisms of the system in various combinations. ¡ We need to account for the irreducible unity of consciousness § i.e. that each experience is irreducible to non- interdependent components ¡ Postulate: there has to be integrated information § in the sense that the conceptual structure specified by the system is irreducible to that specified by non-interdependent sub-systems. ¡ The presence of integration (characterized by big phi or Φ) means that a partitioning of a system of mechanisms would destroy several cause-effect repertoires and change others. ¡ We need to account for the singularity of consciousness in content and spatio- temporal grain § i.e. that there is no superposition of multiple experiences ¡ Postulate: the system of mechanisms must be such that there is no superposition of conceptual structures over elements and spatio-temporal grain. ¡ Tononi and Koch define a complex as the system of mechanisms that generates a maximally irreducible conceptual structure or a quale. ¡ A quale exists in a space called qualia space § the axes of the space are given by all possible past and future states of the complex ¡ Every concept is a point in the space, which specifies the probability of past and future states of the system, given the state of a particular mechanism within it. ¡ The constellation of all concepts together constitutes the “shape” of the quale. ¡ A conscious experience is identical to a maximally irreducible conceptual structure. ¡ The quale completely specifies its § quality (the set of concepts in the quale is the content of consciousness) § quantity (the value of irreducibility Φmax of the quale is the level of consciousness. ¡ IIT is impressive in its scope and detailed and imaginative development of concepts ¡ However: it seems to be embedded in the mechanistic framework of classical physics § Thus: it is likely to inherit the problems that mechanistic approaches to consciousness typically face (the hard problem…) ¡ Can a better account of consciousness be developed if IIT is compared and contrasted with a quantum theoretically inspired approach? § in particular, with David Bohm’s (1990) mind- matter scheme which makes use of a new kind of holistic and dynamic quantum theoretical active information (QTAI). ¡ Bohm himself did not present a specific theory of consciousness § My suggestion: when combined with a higher- order (HO) theory of consciousness, the active information approach can provide a coherent hypothesis about how non-conscious information becomes conscious. ¡ Can IIT help to develop the QTAI approach? ¡ Can insights from the QTAI approach help to develop IIT into a more genuinely holistic theory, and thus more suitable for the task of explaining conscious experience? ¡ Assumption: every particle has a well-defined position and momentum and is accompanied by a field ψ which satisfies the Schrödinger equation 30 How to calculate quantum ‘trajectories’. iS(x,t) Insert the wave function ψ ( x, t)=R(x, t)e− into the Schrödinger equation. Real part gives: ∂S ( S)2 + r + Q + V =0 Quantum Hamilton-Jacobi. ∂t 2m ∂S ~2 2R ¡ EB = PB = S Quantum Potential = Q = r The usual interpretation of QT: the wave − ∂t r −2m R function Ψ does NOT describe an individual [Bohm & Hiley, The Undivided Universe, 1993] quantum system directly § rather: Ψ describes our knowledge of the quantum system to be observed (typically in terms of probabilities) ¡ BH: Ψ describes an objectively real field, guiding a particle such as an electron Schrödinger trajectories Quantum Potential [Philippidis, Dewdney and Hiley, Nuovo Cimento 52B, 15-28 (1979)] Tuesday, 12 June 2012 ¡ Note: R appears both in denominator and numerator ¡ it can thus be multiplied by an arbitrary constant without changing Q § size doesn’t matter here, as a small wave can have exactly the same effect as a large one! § this means that Q (and thus the effect on the particle) can be strong even if the amplitude of the quantum field is very weak. ¡ What matters then? ¡ Note that Q depends on the second spatial derivative of R ¡ This reflects the way in which R changes, or the form or shape of the wave. § note that Q depends only upon the form of the quantum wave! § the quantum wave is NOT pushing and pulling the particle mechanically ¡ Bohm & Hiley: the quantum field encodes information about the whole environment of the particle (e.g. slits) – the field literally IN-FORMS or puts form into the motion of the particle. • The proposal is radical • For BH are in effect suggesting that this type of information ought to be acknowledged as a fundamental – perhaps THE fundamental – category of physics. ▪ “The notion of a particle responding actively to information in the [quantum] field is … far more subtle and dynamic than any others that have hitherto been supposed to be fundamental in physics” (BH 1983). Bohm, D. & Hiley, B.J. (1983), Measurement understood through the quantum potential approach. Foundations of Physics, 14, 3, 255-274. ¡ A form having very little energy enters into a directs