Yes, and as I've mentioned 6 or 23 times now, the real problem is
definitional - which makes all of these arguments somewhat pointless.
If you define consciousness such that only humans are conscious, then
your set of conscious beings contains only humans.
One of the more interesting aspects of this kind of problem is that
most seem to consider the drafting of definitions to be more or less
capricious and arbitrary such that a definition drawn one way or
another becomes a polemical tool. I don't look at it this way. What we
need to understand is what definitions are correct and why. And I'm
not inclined to draw any definition in public relating to mechanical
matters unless I can explain the justification for it in mechanical
terms.
You raise quite a legitimate concern and one that I have considered
and discussed in general terms in different newgroups. The discussion
here has been considerably more neurologically oriented than others
and this has made the topic somewhat inaccessible.
My own approach is not to presume that humans are conscious or not.
Rather it is to say that the differential mechanics underlying
cognition possesses certain mechanical properties that give rise to
various kinds of sentient behavior in categorical terms. That is there
are definite categorically distinct kinds of sentient behavior in
addition to various types or species within each category.
And at the top of the categories is one which is defined in terms of
differences between cognitive differences. Cognitive differences in
themselves define what I call animals capable of locomotion and
cognition or thought. But differences between cognitive differences
yield abstract characteristics of thought which define what I call
conscious organisms possessing voluntary processes of thought.
Now there is no way to determine absolutely which organisms are of
this last type. However the category itself is clear and exists solely
in consequence of the differential implications of cognition in
general and the mechanics associated with the taking of differences.
However in assessing the nature of the last nominally conscious
category of sentient being what we find is that organisms in it would
presumptively have the faculty of predicate language - of things
predicated in terms of one another - would be self conscious and would
presumptively (I know just how silly this sounds but please bear with
me on this one) dress themselves.
Now I certainly understand that this sounds like so much special
pleading on behalf of the human race. However it really is more on the
order of extrapolation of categorical characteristics of differential
cognition. I don't claim that humans are the only coscious beings. I
just claim the the properties of fourth order differences between
differences imply certain characteristics. And among the various kinds
of sentient beings recognizable as having such characteristics there
only seem to be homo sapiens.
One other consideration is relevant here. In an apparently remarkably
short period of time modern humans emerged to populate all reaches of
the earth. And I believe in doing so they would have eradicated any
other potentially similarly conscious organisms. (I'm thinking here of
Neandertals.) Humans certainly seem to have a penchant for killing
each other so I don't see any reason they wouldn't have exterminated
any other potentially proto conscious beings.
Regards - Lester