‘Mary’s Room’: A Thought Experiment

Posted by Keith Tidman

Can we fully understand the world through thought and language—or do we only really understand it through experience? And if only through experience, can we truly communicate with one another on every level? These were some of the questions which lay behind a famous thought experiment of 1982:

A brilliant neurophysiologist, Mary, knows all there is to know about her academic specialty, the science of vision: the physics, biology, chemistry, physiology, and neuroscience. Also how we see colour.

There’s a catch, however: Mary has lived her entire life in a totally black-and-white room, watching a black-and-white screen, and reading black-and-white books. An entirely monochromatic existence. Then, unexpectedly, her screen reveals a bright-red tomato.

What was it like for Mary to experience colour for the first time? Or as the Australian philosopher Frank Jackson asked, who originated this thought experiment, ‘Will [Mary] learn anything or not?’ *

Jackson’s original takeaway from his scenario was that Mary’s first-time experience of red amounted to new knowledge—despite her comprehensive scientific knowledge in the field of colour vision. Jackson believed at the time that colour perception cannot entirely be understood without a person visually experiencing colour.

However, not everyone agreed. Some proposed that Mary’s knowledge, in the absence of first-hand experience, was at best only ever going to be partial, never complete. Indeed, renowned philosopher Thomas Nagel, of ‘what is it like to be a bat’ fame, was in the camp of those who argue that some information can only be understood subjectively.

Yet, Mary's complete acquaintance with the science of vision might well be all there is to understanding the formation of knowledge about colour perception. Philosopher and neurobiologist Owen Flanagan was on-board, concluding that seeing red is a physical occurrence. As he put it, 'Mary knows everything about colour vision that can be expressed in the vocabularies of a complete physics, chemistry, and neuroscience.

Mary would not have learned anything new, then, when the bright-red tomato popped up on her screen. Through the completeness of her knowledge of the science of colour vision, she already fully knew what her exposure to the red tomato would entail by way of sensations. No qualities of the experience were unknowable. The key is in how the brain gives rise to subjective knowledge and experience.

The matter boils down to whether there are nonphysical, qualitative sensations—like colour, taste, smell, feeling, and emotion—that require experience in order for us to become fully familiar with them. Are there limits to our comprehension of something we don’t actually experience? If so, Mary did learn something new by seeing red for the first time.

A few years after Frank Jackson first presented the ‘Mary’s room’ thought experiment, he changed his mind. After considering opposing viewpoints, he came to believe that there was nothing apart from redness’s physical description, of which Mary was fully aware. This time, he concluded that first-hand experiences, too, are scientifically objective, fully measurable events in the brain and thus knowable by someone with Mary’s comprehension and expertise.

This switching of his original position was prompted, in part, by American philosopher and cognitive scientist Daniel Dennett. Dennett asserted that if Mary indeed knew ‘absolutely everything about colour’, as Jackson’s thought experiment presumes, by definition her all-encompassing knowledge would include the science behind people’s ability to comprehend the actual sensation of colour.

To these points, Mary’s factual expertise in the science of colour experience—and the experience’s equivalence and measurability in the brain—appears sufficient to conclude she already knew what red would look like. The experience of red was part of her comprehension of human cognitive functions. Not just with regard to colour, but also to the full array of human mental states: for instance, pain, sweetness, coldness, exhilaration, tedium—ad infinitum.

As Jackson ultimately concluded, the gist is that, given the special particulars of the thought experiment—Mary acquired ‘all the physical information there is to obtain about what goes on when we see ripe tomatoes, or the sky, and use terms like red and blue’—Mary did not acquire new information upon first seeing the red tomato. She didn’t learn anything. Her awareness of redness was already complete.

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* Frank Jackson, 'Epiphenomenal Qualia', Philosophical Quarterly, 32, April 1982.

Is Consciousness Bound Inextricably by the Brain?

From Qualia to Comprehension

Posted by Keith Tidman

According to the contemporary American philosopher, Daniel Dennett, consciousness is the ‘last surviving mystery’ humankind faces.

Well, that may be overstating human achievements, but at the very least, consciousness ranks among the most consequential mysteries. With its importance acknowledged, does the genesis of conscious experience rest solely in the brain? That is, should investigations of consciousness adhere to the simplest, most direct explanation, where neurophysiological activity accounts for this core feature of our being?

Consciousness is a fundamental property of life—an empirical connection to the phenomenal. Conscious states entail a wide range of (mechanistic) experiences, such as wakefulness, cognition, awareness of self and others, sentience, imagination, presence in time and space, perception, emotions, focused attention, information processing, vision of what can be, self-optimisation, memories, opinions—and much more. An element of consciousness is its ability to orchestrate how these intrinsic states of consciousness express themselves.

None of these states, however, requires the presence of a mysterious dynamic—a ‘mind’ operating dualistically separate from the neuronal, synaptic activity of the brain. In that vein, ‘Consciousness is real and irreducible’, as Dennett's contempoary, John Searle, observed in pointing out the seat of consciousness being the brain; ‘you can’t get rid of it’. Accordingly, Cartesian dualism—the mind-body distinction—has long since been displaced by today’s neuroscience, physics, mathematical descriptions, and philosophy.

Of significance, here, is that the list of conscious experiences in the neurophysiology of the brain includes colour awareness (‘blueness’ of eyes), pain from illness, happiness in children’s company, sight of northern lights, pleasure in another’s touch, hunger before a meal, smell of a petunia, sound of a violin concerto, taste of a macaroon, and myriad others. These sensations fall into a category dubbed qualia, their being the subjective, qualitative, ‘introspective’ properties of experience.

Qualia might well constitute, in the words of the Australian cognitive scientist, David Chalmers, the ‘hard problem’ in understanding consciousness; but, I would suggest, they’re not in any manner the ‘insoluble problem’. Qualia indeed pose an enigma for consciousness, but a tractable one. The reality of these experiences—what’s going on, where and how—has not yet yielded to research; however, it’s early. Qualia are likely—with time, new technologies, fresh methodologies, innovative paradigms—to also be traced back to brain activity.

In other words, these experiences are not just correlated to the neurophysiology of the brain serving as a substrate for conscious processes, they are inextricably linked to and caused by brain activity. Or, put another way, neurophysiological activity doesn’t merely represent consciousness, it is consciousness—both necessary and sufficient.

Consciousness is not unique to humans, of course. There’s a hierarchy to consciousness, tagged approximately to the biological sophistication of a species. How aware, sentient, deliberative, coherent, and complexly arranged that any one species might be, consciousness varies down to the simplest organisms. The cutoff point of consciousness, if any, is debatable. Also, if aliens of radically different intelligences and physiologies, including different brain substrates, are going about their lives in solar systems scattered throughout the universe, they likewise share properties of consciousness.

This universal presence of consciousness is different than the ‘strong’ version of panpsychism, which assigns consciousness (‘mind’) to everything—from stars to rocks to atoms. Although some philosophers through history have subscribed to this notion, there is nothing empirical (measurable) to support it—future investigation notwithstanding, of course. A takeaway from the broader discussion is that the distributed presence of conscious experience precludes any one species, human or alien, from staking its claim to ‘exceptionalism’.

Consciousness, while universal, isn’t unbounded. That said, consciousness might prove roughly analogous to physics’ dark matter, dark energy, force fields, and fundamental particles. It’s possible that the consciousness of intelligent species (with higher-order cognition) is ‘entangled’—that is, one person’s consciousness instantaneously influences that of others across space without regard to distance and time. In that sense, one person’s conscious state may not end where someone else’s begins; instead, consciousness is an integrated, universal grid.

All that said, the universe doesn’t seem to pulse as a single conscious entity or ‘living organism’. At least, it doesn't to modern physicists. On a fundamental and necessary level, however, the presence of consciousness gives the universe meaning—it provides reasons for an extraordinarily complex universe like ours to exist, allowing for what ‘awareness’ brings to the presence of intelligent, sentient, reflective species... like humans.

Yet might not hyper-capable machines too eventually attain consciousness? Powerful artificial intelligence might endow machines with the analog of ‘whole-brain’ capabilities, and thus consciousness. With time and breakthroughs, such machines might enter reality—though not posing the ‘existential threat’ some philosophers and scientists have publicly articulated. Such machines might well achieve supreme complexity—in awareness, cognition, ideation, sentience, imagination, critical thinking, volition, self-optimisation, for example—translatable to proximate ‘personhood’, exhibiting proximate consciousness.

Among what remains of the deep mysteries is this task of achiveing a better grasp of the relationship between brain properties and phenomenal properties. The promise is that in the process of developing a better understanding of consciousness, humanity will be provided with a vital key for unlocking what makes us us.