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Zombie Philosophy: Is It Coming For Your Brain?

When I told my friends I was helping to
put together a conference on zombie ethics with the Emory Center for Ethics, I invariably
received one of two responses:

1) That’s really cool! Where do I sign
2) Sorry, what?

If you’re in category (1) and didn’t
manage to make it to the conference, read on to find out what happened. If you’re
closer to category (2), keep
an open mind. There may be more going on with zombies than initially
meets the eye.

Anatomy of a

Dr. Steven Schlozman, an Assistant Professor of Psychiatry at Harvard Medical
School, delivered the first talk of the morning via Skype. Dr. Schlozman, a
zombie fanatic who grew up reading zombie stories and watching movies like Dawn of the Dead, has speculated extensively on what a zombie brain might look like
. First, Dr. Schlozman suggests, zombies likely suffer from an
underactive frontal lobe that leads to impaired impulse control. Frontal lobe
dysfunction might stem from an overactive amygdala, where high levels of
activity have been linked to strong feelings of anger and lust. The anterior
cingulate cortex, which mediates the signal between the amygdala and the
frontal lobe, could also be impaired in a way that eliminates moral restraint. Together,
brain dysfunction in these three critical areas could lead to the insatiable
bloodlust that characterizes most classical zombies.


Dr. Schlozman cited several other zombie
characteristics that may be explained via brain pathology. Impairment of the
ventromedial hypothalamus has been associated with extreme hunger
perhaps explaining zombies’ tireless pursuit of human flesh. Further, the slow,
lumbering gait often associated with zombies, (28 Days Later, Resident Evil, and the recent remake of Dawn of the Dead being prominent exceptions to this rule) may be associated with lesions to the basal ganglia and cerebellum, brain areas
that control balance and motor activity.

If Dr. Schlozman is correct, Dawn of the Dead-type zombies could
conceivably be produced by an appropriate set of neurological interventions.
Yet some philosophers have argued that there may already be zombies amongst us:
what have been called, fittingly, “philosophical zombies.”
 Philosophical zombies are posited as materially identical to normal human
beings, yet lacking in consciousness. We tend to believe that our friends,
family, and coworkers have the same sort of conscious minds that we do, but how
do we really know? Is it possible that a person could have the same brain and body
as me, but not the same mind?

One rendering of the philosophical zombie problem.

Dr. Robert McCauley, Director of Emory’s Center for Mind, Brain, and Culture,
reviewed some of the major arguments for and against the existence of
philosophical zombies. According to McCauley, there are two major strands of
thought in modern philosophy: monism and dualism. Monism posits that the
universe consists of only a single kind of substance. In physicalism, that
substance is material; in idealism, it’s mental or otherwise immaterial. Dualism,
on the other hand, posits that both mental and physical substances exist. Exactly
what it means for a substance to be “mental” or “physical” may be somewhat
unclear, but McCauley points out that despite this ambiguity, we intuitively
have a sense of what these ideas mean. Regardless of what the world actually consists
of, it certainly “seems” that there are physical things, and it “seems” that
there are mental things.

the past several decades, McCauley argues that a new philosophical notion called
psycho-social identity theory (PIT) has risen to prominence. The PIT stipulates
that mental causation and physical causation are one and the same. As a result,
says McCauley, “we know where and how mental causation occurs” – it occurs in
the mind, which is also the brain. PIT has proven to be a useful paradigm for
modern-day neuroscientists, who have used the assumption that “the mind is the
brain” to derive a vast set of empirical findings on how the brain operates.

to McCauley, philosophical zombies have been raised as one of the main
objections to PIT. Some philosophers, most notably David Chalmers, have argued
that the conceivability of philosophical zombies suggests that dualism must be
correct. If it’s possible to imagine an individual materially identical to
myself but with no conscious mind, the argument goes, there must be a kind of
substance that is not material. Other philosophers, including philosopher of mind Daniel Dennett, have argued that arguments premised upon
philosophical zombies are best understood as an “intuition pumps”: thought
experiments that are “wonderful imagination grabbers,” but that rely largely on intuition and often fall apart when exposed to
rational scrutiny. From this perspective, says McCauley, positing a
materially-identical but non-conscious human is like arguing that health can be
removed without damaging organs or materially altering the body.

that PIT’s assumptions are foundational to modern neuroscience, the
plausibility of philosophical zombies has significant implications for
scientific practice. If it’s possible to have a working brain without a working
mind, neuroscience may be missing important data by focusing only on material
brain structures.

Zombie Freedom
Following Dr. McCauley’s talk, Georgia
State associate professor of philosophy Dr. Eddy Nahmias 
considered a related issue: do zombies have free will?

Dr. Nahmias began by asking the audience
to raise their hands if they believed zombies had free will. Nobody, it seemed,
believed that this was the case. Dr. Nahmias then asked if humans possessed
free will, and most (though not all) of the audience agreed that we do. Finally,
Dr. Nahmias asked: why? What is it that grants humans, but not zombies, free
will? Answers to this question varied. Some suggested that human free will
exists due to our ability to suppress “animal impulses” and “instincts.” Others
argued that “working brains” or “personalities” are features that distinguish
humans as unique. Dr. Nahmias, however, suggested that a single principle
underlies all of these characteristics: consciousness. For Dr. Nahmias, zombies
lack free will simply because they lack consciousness.

This issue is important, Dr. Nahmias
argues, in light of controversies that have arisen largely in the last decade
regarding the existence of free will in humans. Daniel Wegner
, Sam Harris, and Jerry Coyne  have all argued that free will is an illusion. According to Dr. Nahmias, these
critiques rely on an implicit model that looks something like this:

My own visual sketch, inspired by a model Dr. Nahmias presented at the conference.

In this model, the brain communicates
with an immaterial thing called the “mind” or “soul,” in which free will takes
place. When the soul has done its work, it communicates a decision back down to
the brain, and the brain causes us to take action. Free will skeptics often
argue that science has demonstrated the soul not to exist, and this being the
case, free will must not exist either.

Dr. Nahmias, however, argues that free
will doesn’t necessarily require any notion of an ethereal soul. Rather, he
argues that we should proceed from the following premises: first, that we have
conscious experience; second, that consciousness is probably located, more or
less, in the cortex; and third, that “it would be shocking” if conscious reasoning
had no effect on action. Given these premises, we can imagine a free will based
simply on the fact that consciousness exists. In this sense, free will exists,
and it influences our behavior insofar as conscious states influence our

Zombies, says Dr. Nahmias, “are a
remarkably effective tool for thinking about free will” because they force us
to more fully examine our intuitions about what constitutes a free being. Clarity
on those intuitions, in turn, is vital to understanding what we mean when we
talk about “free will,” and without that clarity it’s difficult to engage on
questions of whether and to what extent free will exists.

The Case for
There’s at least one other reason why
zombies might be an ideal starting point for public philosophical and ethical
discussions: everyone knows about them, and almost everyone agrees that they’re
at least a little bit cool. Personally, I don’t tend to get all that excited
about zombies – the only zombie movie I’ve seen recently is Zombieland
, and my feelings were mixed – but I’m still a lot more likely
to get involved in a conversation that draws me in with this:

A bloodthirsty zombie.

than, say, this:

Rene Descartes.
It’s probably not a coincidence, then, that Dr.
Scholzman lectures at the Harvard Graduate School of Education in addition to
his work in psychiatry, or that Dr. Bradley Voytek and Dr. Timothy Verstynen  have converted their extended blogosphere discussion of zombie
neuroanatomy into a TedX talk on education
Zombies are the rare commodity that can legitimately compete for the highly
sought-after Educational Triple Crown of philosophical, scientific, and pop cultural
relevance. For that reason, I wouldn’t be surprised if academic discussion on zombies mirrored the modus operandi
of zombies themselves: understated, powerful, and ceaselessly searching for new
brains in which to propagate themselves.

Want to cite this post?

Gordon, R. (2012). Zombie Philosophy: Is It Coming For Your Brain? The Neuroethics Blog. Retrieved on
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