Why is Consciousness a Hard Problem?
The problems of consciousness are difficult because of the
essential innerness, the privateness, of subjective experience.
This is a single difficulty that takes a variety of forms.
A single datapoint: Science relies on inference and
generalization, on comparison, on data-gathering, on the evidence
of the senses.
But I have exactly one data-point on some of the most
essential problems of consciousness: I experience my own consciousness, and
I perceive what it is like to be me; but I can have no direct experience
of anyone else's consciousness.
It is hard to generalize reliably from such a paucity of data.
Opacity to physical instruments: Not only do I have no direct
experience of anyone else's consciousness, but I know of no way
to gather convincing indirect evidence.
There is no physical observation or measurement that I know of
whose results would constitute evidence for or against the
hypothesis that anyone besides me has (or does not have)
(This is because, due to the fact that I have only a single datapoint
to infer from, I have no reliable knowledge about the correlations
between physical facts and subjective consciousness.)
Uniqueness: Consciousness is not like anything else.
Everything else that I experience, I experience through consciousness,
through subjective experience.
The processes by which I come to know about things in the external world
all operate through consciousness, through the having of certain
These processes do not seem suited for giving me knowledge about
These are, clearly, different but overlapping ways of thinking
about the same essential problem.
Some treatments of consciousness attempt to avoid this problem,
in ways that we do not find particularly satisfying:
see "Some unsatisfying answers"
for discussion of some of these.
We eagerly solicit help in this endeavor; suggestions,
corrections, ideas, and references may be sent via email to
David Chess accepts all the
blame, but Steve White gets some of the credit.
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This page last updated January 15th, 2000.