Look at your hand. How do you know it's really yours? It seems obvious, unless you've
experienced the rubber hand illusion. In this experiment, a dummy hand is placed
in front of you and your real hand is hidden
behind a screen. Both are simultaneously stroked
with a paint brush. No matter how much you remind yourself
the dummy hand isn't yours, you eventually start to feel like it is, and inevitably flinch
when it's threatened with a knife. That may just be a temporary trick,
but it speaks to a larger truth: our bodies, the physical,
biological parts of us, and our minds, the thinking,
conscious aspects, have a complicated, tangled relationship. Which one primarily defines you
or your self? Are you a physical body that only
experiences thoughts and emotions as a result of biochemical interactions
in the brain? That would be a body with a mind. Or is there some non-physical part of you
that's pulling the strings but could live outside
of your biological body? That would be a mind with a body. That takes us to an old question of whether the body
and mind are two separate things. In a famous thought experiment, 16th-century philosopher
René Descartes pointed out that even if all our physical sensations
were just a hallucinatory dream, our mind and thoughts
would still be there. That, for him, was the ultimate proof
of our existence. And it led him to conclude that the conscious mind is something separate
from the material body that forms the core of our identity. The notion of a non-physical consciousness echoes the belief of many religions
in an immaterial soul for which the body is only
a temporary shell. If we accept this,
another problem emerges. How can a non-physical mind have
any interaction with the physical body? If the mind has no shape,
weight, or motion, how can it move your muscles? Or if we assume it can, why can your mind
only move your body and not others? Some thinkers have found creative ways
to get around this dilemma. For example, the French priest
and philosopher Nicolas Malebranche claimed that when we think about
reaching for a fork, it's actually god who moves our hand. Another priest philosopher
named George Berkeley concluded that the material world
is an illusion, existing only as mental perceptions. This question of mind versus body
isn't just the domain of philosophers. With the development of psychology
and neuroscience, scientists have weighed in, as well. Many modern scientists reject the idea that there's any distinction
between the mind and body. Neuroscience suggests that our bodies,
along with their physical senses, are deeply integrated
with the activity in our brains to form what we call consciousness. From the day we're born, our mental development is formed
through our body's interaction with the external world. Every sight, sound, and touch create
new maps and representations in the brain that eventually become responsible
for regulating our experience of self. And we have other senses,
besides the typical five, such as the sense of balance and a sense of the relative location
of our body parts. The rubber hand illusion,
and similar virtual reality experiments, show that our senses can easily
mislead us in our judgment of self. They also suggest that our bodies
and external sensations are inseparable from
our subjective consciousness. If this is true, then perhaps Descartes'
experiment was mistaken from the start. After all, if we close our eyes
in a silent room, the feeling of having a body
isn't something we can just imagine away. This question of mind and body
becomes particularly interesting at a time when we're considering
future technologies, such as neural prosthetics
and wearable robots that could become extended parts
of our bodies. Or the slightly more radical idea
of mind uploading, which dangles the possibility
of immortal life without a body by transferring a human consciousness
into a computer. If the body is deeply mapped
in the brain, then by extending our sense of self
to new wearable devices, our brains may eventually adapt
to a restructured version with new sensory representations. Or perhaps uploading our consciousness
into a computer might not even be possible unless we can also simulate a body
capable of delivering physical sensations. The idea that our bodies are part
of our consciousness and vice versa also isn't new. It's found extensively
in Buddhist thought, as well as the writings of philosophers
from Heidegger to Aristotle. But for now, we're still left
with the open question of what exactly our self is. Are we a mind equipped with
a physical body as Descartes suggested? Or a complex organism
that's gained consciousness over millions of years of evolution thanks to a bigger brain and
more neurons than our distant ancestors? Or something else entirely that
no one's yet dreamt up?
