100 Days Blog

Day 029 - Who senses the sensors?

Submitted by Sam on 19 June, 2011 - 01:57

The brain's inability to accurately report on its own hardware is a further reason why intuitions about the non-physicality of phenomenological experience should not be considered authoritative. This inability arises because the structure of the brain has evolved to avoid the costly regress of sensors sensing sensors (or neurons reporting on neurons ad infinitum) in order to be biologically efficient. By avoiding biologically irrelevant complexity to maximize the efficiency of the cognitive system, the machinery of the brain is transparent to the 'self' it generates, thereby preventing clear introspective perception and analysis of its inner workings. From a first-person perspective therefore, accurate analysis (or indeed, awareness) of the physical mechanisms which generate one's own consciousness is ultimately impossible without some form of third-person aid.

As the first-person perspective cannot perceive the physicality of the brain which produces the mind, there is a common propensity towards anti-physicalist intuitions, an illusion which José Musacchio has described as “a serious philosophical handicap1.

In order to understand qualia, therefore, it is necessary to recognize that the nature of mind cannot be accurately explored through introspection alone, as the system which enables this introspection is critically limited in its ability to analyze its own relation to reality. This is not only because of the lack of 'hardware' monitors, but because objective reality is never actually directly available to a consciousness, as all senses which feed it are filtered, trimmed and processed, so that nothing can be perceived directly in some kind of 'raw' state. As we have seen, this filtering is a result of “cognitive shortcuts” which funnel all perceptual information into easily understandable packets, evolutionarily optimized to deal with predators and prey very rapidly, but as a side-effect falsifying reality. Proof of both the success and the fallibility of this system can be found in our ability to accurately perceive physical shapes in the space around us, but yet fall victim to optical illusions which 'trick' the brain into visualizing something which does not exist in objective reality.

  • 1. Musacchio, José M. "Why Do Qualia and the Mind Seem Nonphysical?" Synthese 147.3 (2005): 425-60. Print.

Day 028 - The language of qualia

Submitted by Sam on 18 June, 2011 - 00:52

The physicalists' deconstruction of Jackson's 'knowledge argument', of which Dennett's argument 1 is perhaps the most powerful, has proven so convincing that in 1998 Jackson himself publicly reversed his position in regards to the non-physicality of qualia, rejecting his original knowledge argument as false and accepting that the sensory side of psychology is, in principle, deducible from the physical world 2. In the same article, Jackson re-aligns the question of Mary's room to ask why our intuition that she learns something when she leaves the room is so strong, proposing one possible explanation.

Part of the reason our (or more accusingly, Jackson's) intuition about Mary was wrong can be identified in Dennett's thirteenth 'intuition pump' in Quining Qualia, where the ineffable properties of qualia are challenged based on the practicality of expressing their defining characteristics. Dennett argues that qualia are not substantively ineffable, but are instead only impossible to accurately describe in a practical sense, as language (or indeed any other form of extant communication) can only ever convey an incomplete likeness of the experience in question. The example Dennett uses is the experience of hearing the sound of an osprey cry for real contrasted with reading a description of what to listen for in a bird book, which falls far short of capturing and conveying the experience's 'qualia-complex'.

The intuition that Mary would learn something new seems to arise from an inability to comprehend the true scope of what a complete understanding of 'all the physical facts' about the perception of colour would entail. This misunderstanding is predicated on by the perhaps subconscious recognition that, as a mere human, Mary could never hope to actually possess and understand this level of detail, no matter how brilliant a scientist she happened to be. Subsequently the working definition of 'all of the physical facts' might mistakenly be scaled down into 'all those physical facts which could practically be held in Mary's mind', which would consist of facts that are essentially compact enough to be expressed by a manageable number of words. The sheer number of words necessary to completely specify 'all of the physical facts', to precisely delineate the exact states of every relevant sub-atomic particle and all of their near-infinite interactions, would clearly be too great for any human Mary to ever hold in her mind.

The problem with qualia and the knowledge argument seems to be bound to a problem with language. It may seem intuitive that Mary would learn something new when she sees colour for the first time, but only because we make a tacit assumption that her knowledge is fundamentally human, that is, built on language, resulting in a misleading recalibration of the meaning of her physically complete understanding of the perception colour. In fact, the hypothetical Mary is closer to being a mini Laplace's demon than a 'brilliant scientist', as she would have to possess a practically incomprehensible level of understanding of the physical universe, which would take a correspondingly staggering number of words to specify.

Qualia can't be shared because human language is unable to accurately compress the richness of experience into manageable chunks. Through projects like The Blue Brain Project, however, it seems plausible that qualia could be shared by removing the middle-man, by circumnavigating human language entirely and dealing directly with the fundamental electro-chemical 'language' of the brain itself.

  • 1. Dennett, Daniel C. "Quining Qualia." Consciousness in Modern Science (1988). Print.
  • 2. Jackson, Frank C. "Postscript on Qualia." Mind, Method and Conditionals (1998). Print.

Day 027 - A physicalist response to Mary the super-scientist

Submitted by Sam on 17 June, 2011 - 00:09

Japanese scientist Ken Mogi disagrees with the philosophers who identify an explanatory gap arising from the implications of the Mary's Room thought experiment, insisting that percepts can be fully represented by the interconnected firings of spatially disperse neurons, and therefore that all perception has a foundation in physical phenomenon. He keeps company with the philosopher and cognitive scientist Daniel Dennett when he claims that “the time has come, when qualia is to be liberated from the studies of philosophers, and to become a subject of an empirical science” 1.

Dennett made the argument that if Mary truly knew everything there is to know about colour, she would necessarily have to have an unimaginably precise atomic-level understanding of the neurology of the human brain, and would therefore be able to interpret the minute changes in the brain's electro-chemistry that each stimulus would produce, and thus would have a complete understanding of the stimulus' corresponding quale. Dennett asserts that the thought-experiment is misleading because whilst it requires 'all physical knowledge', such an omniscient state is unimaginable for a human to possess, and so twists our intuitions. If she really did possess all physical knowledge, she would be able to pre-determine the electro-chemical morphology of her brain when it is presented with a colour stimulus, and would therefore be able to accurately model her 'experience' of seeing colour for the first time.

In order to further elucidate this claim, Dennett uses the hypothetical example of 'RoboMary', an exceptionally intelligent robot who perceives the world through a monochromatic software filter. Other robots exist like RoboMary, but who are able to perceive the world with colour vision. RoboMary is able to create a simulation of the colour-vision of these robots (which is ultimately entirely determined by their software and circuitry), and is able to see exactly how their internal states are configured when they are presented with a coloured impulse. With reference to the internal states of the other robots, she is able to project exactly how she would react without a monochromatic filter when presented with colour. In doing so, she is able to know exactly what it is like to see the colour red, without actually ever having seen it in reality.

Day 026 - Mary's room

Submitted by Sam on 15 June, 2011 - 22:54

One of the most widely discussed philosophical thought-experiments about qualia was proposed by Frank Jackson in his 1982 article “Epiphenomenal Qualia”, and is known variously as 'Mary's room' and 'Mary the super-scientist'.

In this thought-experiment, Mary is a scientist who is confined to a monochromatic room, and has never been exposed to colour. She is a brilliant scientist, specializing in the neurophysiology of vision, and we are to suppose that she obtains all of the “physical information” that exists on what happens when colour is perceived; in short, she knows everything there is to know about colour, but she has never experienced it. Jackson asks what will happen to Mary if she is released from her black and white room and sees colour for the first time – will she learn anything or not?

If she does obtain new knowledge when she leaves the room, then the implications are that qualia exist, and that perfect physical knowledge is inadequate to describe all experience. This is what Jackson concluded in 1982:

“It seems just obvious that she will learn something about the world and our visual experience of it. But then it is inescapable that her previous knowledge was incomplete. But she had all the physical information. Ergo there is more to have than that, and Physicalism is false” 1.

Others have taken a similar view, concluding with Jackson that Mary would learn something new when she sees colour for the first time, and thus there must be an unbridgeable gap between the physical and the mental worlds, and that experiences and feelings must have subjective, non-physical qualities. This is known as the explanatory gap, and its strongest proponents (antimaterialists) argue that it can never be closed, and that the mind is substantially and qualitatively more than the sum of the brain's physical parts.

  • 1. Jackson, Frank (1982). "Epiphenomenal Qualia". Philosophical Quarterly (32): 127–136.

Day 025 - The trouble with qualia

Submitted by Sam on 15 June, 2011 - 01:25

Our brains have evolved to consciously parse only the most relevant and important information from our senses, making them more like filters than windows to the world, as Robert Ornstein observed in his 1986 book, Multimind. Through this filtering process comes subjectivity, and its attendant philosophical problems, notably qualia, or the ineffably subjective quality of conscious sensation; the perception of the sensation of the colour red, 'the redness of red'. An example of one of my own most distinctly identifiable qualia is my sensation of gut-wrenching dread whenever I hear a specific alarm-clock tone. Other people will have their own widely different feelings and experiences associated with this particular tone, and hence their own quale associated with it.

Qualia are deceptively complex because they inhabit the liminal space between the physical and the mental worlds, and are thus a central component to the mind-body problem. A great deal of philosophical debate has arisen from qualia, broadly centred around whether these subjective experiences can be described by purely physical information or not – i.e. whether they can ever exist without being experienced. Can I ever know what it is like to experience your sensation of the colour red? Whilst we have already heard a neuroscientist's answer to this question from Henry Markram at The Blue Brain Project, it is interesting to contrast his physicalist perspective with the numerous philosophical thought experiments which have been devised to answer this question, which I shall be looking at over the next few days.

In the meantime, here is a quick overview of qualia from Dr Ramachandran.

Like all components of living organisms, the evolution of conscious systems has been shaped by selection pressures which favour energy-efficient and resource-saving architectures. Conscious systems have been optimized by many generations of natural selection to process and store only the most relevant and essential information.

The human mind is an extremely compact conscious system, saving both space and time by perceiving and remembering a simplified but very organized version of the environment rather than a resource-hungry one-to-one objective replica. To defer to Stan Franklin once more, a useful analogy for visualizing this optimization is to compare a stored table of the first x prime numbers with a formula which calculates them on demand. The formula is much more compact, potentially requiring much less memory (as in bits) than a large look-up table, and so is preferable in systems where memory is at a premium. This compression results in a species-wide subjective experience of the real world, and one manifestation of it can be tested through psychophysical experiments.

Psychophysics is a branch of science concerned with the quantitative relationships between mental states and physical events and processes, exploring the intersection of the subjective with the objective in order to make subjective internal transformations measurable.

The Weber-Fechner law is an historically important psychophysical attempt to describe the relationship between the magnitudes of stimuli and their perceived intensity. By recording when a person was able to distinguish between two nearly identical stimuli, such as two similar weights, it was found that the smallest noticeable difference between them was approximately proportional to the intensity of the stimulus, so that the threshold for distinction varies according to the intensity. This means that a weight increase of a few grams on a 1kg weight is undetected, and is only perceived when a critically increased threshold mass is reached; and if the mass is doubled then the threshold is also doubled. This describes a logarithmic relationship between stimulus and perception, illustrating how the world our energy-efficient brains create is affected by internal transformations.

The Stevens' power law offers several refinements to the logarithmic relationship described by the Weber-Fechner law, showing that whilst our visual perception of length may be linear, our perception of brightness is logarithmic and our perception of pain is exponential, further revealing that what we perceive does not infallibly correlate with the physical world, but is instead mediated by the wiring of our brains.

Day 023 - Degrees of mind

Submitted by Sam on 13 June, 2011 - 00:27

By exhibiting over the course of its life a descending order of 'mind', moving from a small but adequate nervous system – a very low degree of mind – to almost no nervous system at all – a negligible degree of mind, the sea squirt's extraordinary metamorphosis draws attention to the possible existence of degrees of mind, a spectrum of complexity which would place bacteria at one extreme and humans at another. The following syllogism from Stan Franklin helps to clarify this particular definition of mind, which has a much wider reach than the dictionary definition provided by the OED, where the mind is described as a phenomenon peculiar only to human beings 1. Franklin sees mind as that which controls behaviour, noting that bacteria behave, and so must therefore possess some degree of mind in order to control their behaviour.

The sea squirt suggests that even very basic minds are expensive to maintain, requiring valuable energy and resources that are conserved at the earliest opportunity. Possessing a mind must therefore outweigh the costs of fuelling it, and so selective evolution must ensure that a balance is maintained between the degree of mind and the resources required to run it. As the complexity of mind increases, any energy-saving optimizations are preserved. The consequences of this architectural trait are important for an understanding of the human mind, and I'll look at some of them in tomorrow's blog.

  • 1. The OED definition of mind as a mental or physical faculty is: 'The seat of awareness, thought, volition, feeling, and memory; cognitive and emotional phenomena and powers considered as constituting a presiding influence; the mental faculty of a human being (esp. as regarded as being separate from the physical); (occas.) this whole system as constituting a person's character or individuality'. "mind, n.1". OED Online. March 2011. Oxford University Press. 12 June 2011 http://oed.com/view/Entry/118732?rskey=s5NKU5&result=1&isAdvanced=false

Day 022 - Sea squirts – no more deciding

Submitted by Sam on 11 June, 2011 - 21:47

The life cycle of the sea squirt features a remarkable metamorphic transition where the animal absorbs its own rudimentary brain. This extreme change is brought about by the sea squirt achieving the uniquely rare state of having no more decisions left to make.

Sea squirts are living representations of some of our most primitive ancestors, belonging to the same phylum that we do (Chordata) because of the basic vertebrate features which characterize them during their early life as larvae. In their larval form, sea squirts resemble small tadpoles, and are able to swim around freely. In this form, these small marine animals possess a notochord (a flexible rod-shaped “backbone”), a tail, a primitive eye, and a balance organ, making them an effective dispersal mechanism for finding a suitable habitat for their adult life. They swim around in this form until they find a suitably hard surface, perhaps a rock, a ship's hull or the back of a large crab, to which they will attach themselves by standing on their head and using specialized organs of attachment, papillae, to permanently adhere themselves.

Once attached to the solid substrate where they will spend the rest of their lives, the metamorphoses begins. Within a single day, the sea squirt absorbs most of its tail, its nerve cord and its notochord – all of the features that classify them as chordates. As their larval features quickly degenerate, the larval organs are reabsorbed and replaced with an adult set more suited to a sedentary life, and the sea squirt becomes “an entirely new animal” 1.

Firmly fixed in place, filter-feeding food particles from the water, the complex machinery of a brain is simply superfluous to the sea squirt's now sessile life. Having achieved its ultimate purpose of deciding once and for all what to do next, the brain is no longer needed, and so is absorbed. The sea squirt's metamorphosis can be seen as a stark validation of Stan Franklin's interpretation of the single purpose of mind being to choose what to do next.

  • 1. Dethier, Vincent G. "The Magic of Metamorphosis: Nature's Own Sleight of Hand." Smithsonian 17.2 (1986): 122

Day 021 - The what-to-do-next machine

Submitted by Sam on 10 June, 2011 - 23:47

So what is the purpose of all of this emergent behaviour? Is there any point to the intelligence that all of these independently limited components join together to achieve? For Stan Franklin, Interdisciplinary Research Fellow at The University of Memphis and co-director of the Institute for Intelligent Systems, all of the richness of mind is directed towards one easily expressible goal; to decide what to do next 1 .

On the most basic level, every flash of electro-chemical activity in a neural network is in essence a calculation, moving the system from one state to another, processing inputs into outputs. Because of this basic architecture, brains are constantly performing operations, locked into a cycle of deciding what to do next, as the neural network processes calculations over time to produce the conscious sensation of weighing-up facts to make a high-level decision. From a behavioural perspective, all of these operations are performed in order to effect the optimal next move for the organism's well-being, processing all available variables to produce a consensus of action which will, ideally, benefit the organism in some way.

To make informed decisions, thinking organisms must be hard-wired with some fundamental inherited values against which to measure all other decisions; without such a benchmark, one action is as good as another. At some basic level, all decision-making organisms must have some invariant autonomous goals, preferences and standards, against which all other decisions can be compared. Some identifiable goals might include: eat, drink, mate, avoid pain. Again, in order to satisfy these basic drives, the organism needs to be constructed either with some minimal knowledge necessary to achieve these goals, or with the means to learn how to do so.

  • 1. Franklin, Stan. Artificial Minds. Cambridge, MA: MIT, 1997

Day 020 - Superorganisms

Submitted by Sam on 9 June, 2011 - 21:44

An interesting analogue can be drawn between the emergent complexity of the local interaction of neurons and the collaborative behaviour of superorganisms such as ants. Collectively, both ants and neurons exhibit emergent group intelligence in a strikingly similar manner. Colonies of ants and neural networks achieve things that no individual component can achieve on its own, as neurons link together to produce circuits of logic gates with universal computational capabilities, and as ants collaborate to build and maintain highly structured societies and intricate nests of excavated tunnels and chambers.

Ants are well-known examples of eusocial animals, each performing highly-specialized tasks. Harvester ants, for example, can be categorized into four distinct categories, based on the tasks that they elect to perform: patrolling, foraging, waste management and nest maintenance. Based on local information, ants decide to switch between tasks, producing coordinated emergent behaviour and patterns of global work which create a very stable colony.

With this specialization and exceptionally well-organized division of labour, each ant in a colony can be seen as an individual component of a much larger system in much the same way that, for instance, a neocortical column can be seen as a discrete functional unit of the brain. In this way, ants and neural networks exhibit a strikingly similar form of distributed intelligence, whereby cooperative agents of minimal individual intelligence achieve system-level goals far beyond their individual capabilities. Through such compartmentalization and modularity, both brains and ant colonies have evolved into systems which are self-evidently highly robust, reliable and scalable.

The similarities between the two systems are extensive. Like neurons (and Reynolds' boids), ants act in accordance with simple rules and local information – they are not controlled by a centralized body which oversees the colony 1, but are instead reactive only to a small set of simple chemical signals released by other ants. At this level of abstraction, the ants communicate just as neurons communicate at synapses, where chemical neurotransmitter is released in a highly localized environment.

Neuro-structural reassembly, the brain's process of reducing the overall number of connections to leave only the most efficient, shares many common features with the emergent optimization of ant food-gathering. An ant collecting food leaves behind it a particular pattern of pheromones which other drones will smell and follow towards the food source, and over time the most direct path to the food will become the most successful as more and more ants follow it and reinforce it, forming their distinctive trail. This self-organizing, short-cut-taking behaviour bears a strong resemblance to how the brain wires itself during development.

Similarly, if an ant colony becomes overcrowded or damaged, scouts will leave the nest to search for a new site. Once more using pheromone trails, the ants 'decide' on a new site when a critical threshold of scouts 'agree' on a particular location for a new nest. Research 2 has shown a very similar process occurring in a monkey's visual cortex when it performed a visual discrimination task. Neuron activity gradually increases until a threshold is reached, and the monkey makes a decision.

Ant colonies provide a high-level metaphor for the organization and logic of the brain, usefully illustrating how comparatively simple individual elements can join together in a distributed, decentralized fashion to produce complex, intelligent behaviour.

  • 1. The queen ant is a deceptive term – she has no overall control over her children in the colony, and serves only to continually reproduce.
  • 2. Valeo, Tom. "Researchers Begin to Decode Decision-making Processes - Dana Foundation." Brain and Brain Research Information - Dana Foundation. Web. 09 June 2011. http://www.dana.org/news/brainwork/detail.aspx?id=14382.
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