Brains: Philosophical Zombies, Thought Experiments and Consciousness

Brains: Philosophical Zombies, Thought Experiments and Consciousness

The thought experiment of the philosophical zombie has found itself an audience of supporters and detractors.  Modern adaptations of this concept have extended further to include entire worlds populated by the philosophically undead.  This philosophical zombie asks us to thing about the nature of consciousness, all the while pondering whether zombies can exist.  Additionally, this experiment demonstrates the limitations of thought experiments and the limitations of our own consciousness.  In this essay, the most common explanation of the philosophical zombie will be expressed.  The various sides of the thought experiment will be explained as well.  The conclusion will demonstrate how this particular experiment fails. 

The thought experiment of the philosophical zombie was written about extensively by David Chalmers in his 1996 book The Conscious Mind.  This work built on the prior ideas of philosophers like Saul Kripke.  The philosophical zombie is a creature, not a person, who is, molecule for molecule identical to an ordinary living, breathing human being, except for one important difference; the zombie has no consciousness.  It looks and feels just like any sentient being on the planet but does not feel or think.  This zombie twin has physical function and physiological organization the same as people.  Additionally, behavior is replicated by neurologic function.  For example, should the zombie be prodded with a red hot fireplace stoker then the zombie would react in the same painful manner as any ‘normal’ human.  Since we can conceive of such a creature, as the argument goes, they are possible, at least metaphysically.  Had the circumstances of the natural world been different, zombies could have very well existed or exist (Kobes, 2007).  Ultimately, the experiment is an argument against the idea that everything in our world has a physical basis, including consciousness. 

The debate today is rather vigorous.  Some argue that any zombie like that in this thought experiment could not be exactly like us.  Aspects of our perception, a part of our consciousness, would not be available to the zombie.  And, if our consciousness is a causal relationship between sensory inputs and behavioral outputs, there is no way for the zombie to be, molecule for molecule, like a person (Pratt, 2013).  Essentially, if it walks like a human and it quacks like a human then it must be a human.  Others argue that a zombie could evaluate their visual perceptions in terms of environmental contrast and behaving in that environment.  The counter argument is that since the zombie lacks a ‘normal’ consciousness, experiences and perceptions are not a factor.   Another group of philosophers state that, once a zombie comes into being and begins interacting with its environment that those experiences start to form a type of consciousness (Pratt, 2013).    A fourth group argues that any being, or creature, with analytical mechanisms, would experience consciousness.  If this philosophical zombie is biologically identical to sentient humans, then they would experience some sort of consciousness (Loosemore, 2009).  As zombies search for brains, they must interact with their environment and analyze and experience their surroundings.  Some do not argue about the veracity of the philosophical zombie, rather they state that the argument itself is circular and, therefore, not valid.  The idea that something physically identical to a human being but lacking subjective experience would assume that subjective experiences do not produce consciousness, which is what the experiment is trying to prove (Brown). 

All of these stances, arguments and counter arguments suppose that we know something about consciousness.  However, this supposition leads to a very difficult problem, what Chalmers calls the ‘hard problem.’  To date, no scholar, philosopher or academic has proved, convincingly, a casual explanation of how and why we are conscious.  There has been no conclusive evidence showing that we are not, in fact, zombies (Harnad).  To many, consciousness has multiple meanings.  Consciousness can mean that a being is ‘awake,’ alert and aware of one’s surroundings.  Taken a step further, it can also mean that the ability to have intentions, purposeful thoughts and behaviors.  To conceive of a thing is also to conceive of what that thing lacks.  Therein lies the problem.  How can we conceive of a thing that cannot, itself conceive of that thing that we cannot even define (Loosemore, 2009)?

It is very easy for any individual to conceive of zombies.  The Walking Dead, Sean of the Dead, Night of the Living Dead and Zombieland are but a few examples of zombies in popular media.  As such, zombies are definitely possible in one’s imagination.  This thought experiment is based on the assumption that what we can conceive must be possible.  This shows a limitation of thought experiments themselves.  All thought experiments, from the Chinese Room to a tree falling in the forest, rely on conceiving a certain set of properties.  And, while truth might be stranger than fiction, the fictions that can be conceived by humans can be complex and varied.  Ultimately, any conceived parameters and properties are just that: fictions created in one’s imagination. 

A better thought experiment could easily be found.  One would be to simply imagine two identical human beings living on two different planets.  One could be called Bob(Earth) and Bob(Mars) and their consciousness could be debated.  However, there already exist two identical individuals on this planet: identical twins.  We can call this the Twins Experiment.  Their experiences can be created and conceived.  Then, their consciousness can be debated and examined.  Various philosophers and scholars can publish volumes on the subject.  Perhaps, this experiment may yield some answers; perhaps, it may arrive at a definition of what constitutes consciousness.

However, for the sake of the thought experiment, this author will ponder whether such a creature could exist and what it might mean for our consciousness.  Zombies lack agency, the ability to perform actions in the world.  Performing behaviors requires some thought, some ability to have a meaningful actions, even if it is only for brains.  Therefore, any actions made by such a zombie must be governed by extraneous electrical impulses that can contract muscles or by our autonomous and parasympathetic nervous systems.  However, it seems implausible that, without a consciousness, we would only want to consume human flesh.  If that were the case, that zombies function on mere impulse, but can we call the unfortunate soul on hospital life support a zombie?  After all, they could react to certain stimuli.  It would hardly seem appropriate to call them zombies.  Perhaps this is because we conceive of zombies like those in 28 Days Later.  Supposing that zombies are logically possible requires at least two beliefs.  First, that something can be true if it can be conceived.  Simply put, zombies are not possible with the current natural order of things.  Put another way, the existence of zombies have not empirical truth.  The reality of a philosophical zombie requires belief in conceptual truth, that what can be imagined has the ability to be real.  Second, that consciousness must be something that transcends words which would draw into question the appropriateness and veracity of any thought experiment dealing with consciousness.  After all, a thought experiment ceases to be a thought experiment if they are so implausible as to elicit more discussion about the validity of the experiment than engagement with the experiment itself.

References

Brown, R. (2010). Deprioritizing the a priori arguments against physicalism. Journal of Consciousness Studies, 17(3-4), 47-69.

Harnad, S. (1995). Why and how we are not zombies. Journal of Consciousness Studies, 1(2), 164-167. 

Kobes, B.W. (2007). Functionalist Theories of Consciousness.  In T. Bayne, A. Cleeremans & P. Wilken (Eds.), Oxford Companion to Consciousness. Oxford: Oxford University Press.

Loosemore, R.P.W. (2009). Consciousness in human and machine: A theory and some falsifable predictions. In B. Goertzel, P. Hitzler & M. Hutter (Eds.), Proceedings of the Second Conference on Artificial General Intelligence (Arlington, March 2009). Paris: Atlantis Press.

Pratt, M. (2013). Redefining the class of qualitative states – A reply to Shoemaker. Res Cogitans, 4(1), 52-62.