Challenges to Cartesian materialism: Understanding consciousness, naturalism and the mind-world relation

Transcription

1 1 Challenges to Cartesian materialism: Understanding consciousness, naturalism and the mind-world relation Jonathan Knowles standing_naturalism_and_the_mind-world_relation

2 2 Overview Descartes and the problem of mind in a physical world Overview of different contemporary responses to the hard problem of consciousness Cartesian materialism (CM) Why challenge CM? Enactivism Problems for enactivism A non-reductive approach to consciouness A neo-pragmatist metaphilosophy

3 3 Descartes on Mind and Matter

4 4 Central problem in the philosophy of mind since Descartes How does the mental fit into a physical world? Focus on consciousness. Core of problem here derives from two conflicting intuitions: A) Our concepts of consciousness and matter seem distinct: I can think away everything but conscious thought from the nature of myself, therefore mind and body are substantially distinct (Descartes). We can imagine creatures physically just like us and behaving just as we do, but with different conscious experience ( inverted spectra ) or with no conscious experience at all: Zombies (David Chalmers). Assuming these thought experiments are genuine guides to possibility, consciousness properties physical properties, seemingly.

5 5 David Chalmers, ANU, author of The Conscious Mind (OUP 1996)

6 6 On the other hand B) Everything in the world has a sufficient physical cause, including our actions ( the completeness of physics ). So either conscious events (having a pain, seeing red, hearing music) are identical with or somehow realised in physical causes (contra the Zombie Argument), or they are epiphenomenal. But the latter seems absurd, for surely it is my pain that makes me jump. So we have a paradox/puzzle, sometimes expressed as the hard problem of consciousness: why does anything physical feel a certain way. Elicits a range of different responses in contemporary philosophy of mind. A philosophical paradigm! Most retain the belief, in light of advances in the cognitive and neurosciences, that the conscious mind is somehow physical and realised in the brain.

7 7 Classical cognitive science (1950s-) Accepts that everything mental supervenes on the physical/neural as at least a working hypothesis. Focus originally on capacities involving inference/reasoning/thinking e.g. language production/understanding, early visual processing, solving mathematical problems etc. Now Descartes also thought reasoning was non-physical, since creative/non-mechanical. But modern computer science (cf. esp. Turing) has shown that we can reduce many kinds of intellectual problem to computational problems which can be realised in a physical device. Leads to central metaphor of CCS: brain = computer, where neurons etc. are hardware, and reasoning, planning, perceiving etc. are programmes run on this. Data structures = internal representations, with contents fixed by relations to ovjects/properties in the external world More integration with neuroscience in recent years, cf. e.g. Bechtel.

8 8 Some recent theories about consciousness within CCS Consciousness is a kind of higher-order representation (Rosenthal, Carruthers) Consciousness is a special kind of first order representation of the world/body (Tye, Dretske) Consciousness is a higher level (functional) neural property, e.g. informational integration (e.g. Baars, Tononi). Consciousness is a special first-order neural property ( biological theory, Block)

9 9 More radical gambits We can never understand how the brain gives rise to consciousness, though there is an answer ( Mysterianism, e.g. McGinn). Panpsychism/property dualism: mentality/consciousness is part of the very fabric of physical reality. Animal consciousness involves a special organisation of physical stuff already endowed with protopsychic properties, or is a special force in the brain needed to collapse the wave function (Chalmers). Consciousness is epiphenomenal (Jackson). There is no hard problem, the idea that there is arises from mixing up the third and first person perspective. Scepticism about a special what it s like category and an inner Cartesian theatre where this is all inspected by the mind, e.g. Dennett. All we have is what people tell us about what they perceive/experience, and our job as researchers is to find out what the real mechanisms are in a way that explains why people report what they do, but also how they behave in experimental settings.

10 10 Cartesian materialism (CM) What all these (more or less) accept is that conscious experience is a real phenomenon identical to, realised in or somehow produced by complex brain states/processes. Instead of a dualism of mind and matter we have a dualism of brain and body/environment: Cartesian materialism. As far as my consciousness is concerned, I could be a brain in a vat

11 11 Brain in a vat

12 12 Challenging CM Why do it? Isn t philosophy/science just hard? The very terms of the hard problem of consciousness seem set up to make it unsolvable (Evan Thompson, Mind in Life). At least there is absolutely no consensus on how to make progress on it. Why believe the brain is the seat of consciousness? Is this more than a dogma? If it isn t, there is arguably no clear demaraction in physical reality between the realms of the conscious and the non-conscious, in which case, why think that understanding physical reality will yield an understanding of consciousness? One can raise questions about the prevailing methodology/explanatory assumptions of classical cognitive science/philosophy of mind: notions of function/behaviour/reference/anything physicalistically respectable given, whilst phenomenology, what it is like, is to be explained. So good motivations exist for questioning CM exist. But how, concretely, should we provide a better understanding? Can we do so, and in a way that is recognizably naturalistic/scientific?

13 13 Enactivism about conscious experience Enactivism part of a complex and many-faceted movement or set of movements within recent cognitive science, often known as 4e, that opposes CCS: 4e: Cognition is embedded, embodied, enacted, and extended (cf. Andy Clark, Susan Hurley, Rodney Brooks, Evan Thompson, Mark Rowlands, Dan Hutto, Tony Chemero et al.). Meant to be anti-cartesian, though controversial as to how and to what extent. Common denominator is that intelligence/mentality needs to be explained much more contextually and that this will diminish (at least, alter) the role played by internal representations and the brain. Our focus: Enactivism as developed by Alva Noë and Kevin O Regan: Heavily influenced by the phenomenologists, esp. Husserl and Merleau-Ponty. Perceptual experience is an extended temporal process involving dynamic interaction with the environment, undergirded by implicit knowledge of sensorimotor contingencies ( laws ). We need to think of vision as more like touch and less like taking a snapshot of the world. This will help solve/dissolve the hard problem.

14 14 Noë and O Regan, Senorimotor account of visual consciousness

15 15 Experience is not like this

16 16 More like this?

17 17 What visual experience is like according to O Regan/Noë Dennett agrees with the negative point, but then argues that the richness of experience is an illusion. Others say that we/our brain builds up an internal picture from snapshots of it together with top-down inferences. O Regan/Noë: Visual experience of the world as evenly and richly detailed is not an illusion but is due to the fact that the world itself is rich and we are able to visually sample it through action (or know we can). Visual experience is not something that happens to us, a representation, in the brain. It is an enacted process, something we do, that involves body and world. Somehow this (helps) to solve the hard problem of consciousness.

18 18 Some more empirical evidence Change/inattention blindness: We are not good at noticing features of our visual scenes that are not relevant to our practical projects: Knowledge of sensorimotor contingencies: Tactile visual sensory substitution systems recreate phenomenology of vision.

19 19

20 20 Assessing enactivism: empirical problems

21 21 Assessing enactivism: principled problems Core ideas behind enactivism: Perceptual experience is determined by sensation, action, the external world and knowledge of sensorimotor contingencies. But even if this is right, why should any of this feel a particular way ( the hard problem )? Does it make sense to suppose the external world feels at all? And if all the feeling drains down to the sensations, which are assumed to be neural, where is the advance on CM? It seems it can t be true that I need to act to see, but only to know what would happen if I did. Does knowledge feel any particular way? Can t it in any case be realised in the brain? Enactivism per se doesn t seem to go far enough in regestalting our thinking about consciousness.

22 22 What we need to acknowledge Consciousness is essentially a person- or organism-level phenomenomenon. It makes no literal sense to say that my brain sees or feels this, that or the other. But nor is it any better to think of experience as being in objects in the external world. Thinking there is a good question of where experiences are to be found is simply a category mistake pace Noë: [W]e are looking for consciousness in the wrong place if we look for it in the brain. (Out of Our Heads, p. 65). Consciousness is as such fundamentally intentional: a matter of having the (or a) world presented/revealed to one. It is only to a subject of experience that attributions of consciousness make sense, and this involves attributing it an apprehension of a world.

23 23 What we need to acknowledge-2 Phenomenological analysis (Brentano, Husserl, Heidegger, Merleau-Ponty, Sartre) therefore can indeed must contribute directly to any science of consciousness. Phenomenology is a first-personal form of analysis but is not a matter of introspection, but rather of detailing the structure of lived, embodied experience involving inter alia our direct contact with wordly objects (though conceived of independently of theoreticall assumptions about their underlying physical nature). Phenomenology thereby aims to reveal the principles underlying conscious experience qua the lived, experienced world. In seeing consciousness as something neither in the head nor in the physical world, the assumptions driving the hard problem of consciousness are obviated and the usual debate not joined. A naturalist should however reject the traditional transcendental/aprioristic/idealistic conception of phenomenology. But this is compatible with the primacy of phenomenological analysis in the study of consciousness. Together with input from empirical studies and indeed an understanding of the brain, we can in this way make progress towards a scientific understanding of consciousness one that will be able to mesh with the insights and general approach of enactivism, freed of its reductive ambitions.

24 24 Does this really solve the problem? Does this really change anything with respect to the hard problem of consciousness? Don t we still have to face up to the fact that at some point in the history of living things consciousness sprang up out of purely physical processes? And isn t this still a huge mystery, and the central explanandum? Yes and no: our anti-reductive account provides a new way of thinking about consciousness science, one that may also mesh with fundamental thinking about the logic of life and the idea that life/consciousness is an emergent phenomenon (cf. Varela/Maturana/Thompson on autopoiesis). OTOH we are still left with a question about how life emerges from the primordial slime, what it is to be thus emergent etc.

25 25 Neo-pragmatism (Kuhn/Rorty/Price) needed too Think of our predicament in terms of our having on our hands two broad but incommensurable discourses: the discourse of fundamental physics/physical processes on the one hand, and the discourse of experience/the lived world/life on the other. There will of course be there are connections/overlaps between the discourses, and our knowledge as a whole must aim for a certain overall coherence. But we do need to see the discourses as ideally fitting in to one allinclusive story about reality? Cp. Nils Bohr: There is no quantum world. There is only an abstract quantum physical description. It is wrong to think that the task of physics is to find out how nature is. Physics concerns what we can say about nature. I agree, but do we even need the category of nature/reality? Being a neo-pragmatist is arguably good practice in science generally, as well as, arguably, being the only viable response to the age-old epistemological problems of philosophy.