Post by Ben NewsamOn 15 Oct 2006 22:12:13 -0700, "tension_on_the_wire"
Post by tension_on_the_wireFor us to have the pain system we have now, it
had to have started long before mammals were
even mammals as we know them. It is not
possible for us to feel pain, and cats not. It
would imply that our entire human nervous system
evolved over the last 2 million years and anyone
who thinks that has not a single clue about the
evolution of species on earth.
I'm not sure that's entirely true. The nervous system certainly
carries the signals that produce both pain and pleasure, but the
interpretation of sensation is done in the brain, which presumably has
to decide a spectrum of acceptability of all sorts of sensations of
different sorts. That is, assuming that you do not categorise the
brain as part of the nervous system, which, although it undoubtedly
is, I treat as separate for the purposes of this discussion. For
instance, if I stand in front of a radiator, I experience a very
pleasant warming sensation in my backside. If I continue the
experience a bit too long, it becomes uncomfortably warm. At higher
temperatures, the heat becomes unbearable, and sooner or later it
produces what I call pain. Similarly, the point of a knife on the skin
will produce a slight, possibly even pleasant tickling sensation,
followed by a sharp pricking, followed later by intense pain. It's
merely a matter of degree and interpretation. That being said, I have
no reason to suppose that a cat has any less need for signals to be
interpreted as pain than we do.
Well, I'm trying to see why that disproves anything I said about
the length of time evolution takes to produce the complex
mammalian nervous system. If anything, it bears me out.
The nervous system, including the brain, is extremely
sophisticated in the handling of sensory signals. There are
completely different sets of nerves and spinal tracts that go to
different parts of the brain for processing heat/cold vs.
pinprick/pain vs. light touch vs. proprioception (the knowing of
where exactly your hand or foot is in space).
And for what it's worth, it isn't just the brain arbitrarily deciding
what constitutes a comfortable versus uncomfortable sensation.
That is also partly indicated by the intensity or amplitude of the
signal coming from the peripheral nerves, as well as the
frequency of firing of those nerves. The pleasant warming
sensation in your backside will be perceived as such by the
brain partly because the brain has "learned" that when the
nerve fires with less intensity or frequency it represents
less heat...but when the nerve fires with higher intensity
or very high frequency it is a danger signal which is then
perceived as pain. It takes certain intensities and frequencies
to trigger the endorphin response which takes place strictly
in the brain. So it is all interconnected as one smoothly
functioning system and you cannot really separate the
brain from the peripheral nerves as if they function
separately because they don't. At least not well, as
is seen in cases where one or other part of the system
is disrupted.
In quadreplegics, the peripheral system has been
alienated from the brain....neither pain nor any other
sensation is discernible. In amputation patients,
the phenomenon of "ghost pain" can continue for
years even though there are no signals triggering
the peripheral nerves. In organic brain damage,
such as stroke, there can be either inability to
perceive pain or to make a motor response to
move away from pain. In diabetes, the longterm
damage to peripheral nerves makes the feet in
extreme danger because of the person's lack
of ability to feel small damage and attend to
small wounds heightening the risk of infection
and gangrene. The nervous system is highly
integrated throughout the functioning of the
body at all levels, which indicates even more
the millenia it must have taken to evolve such
a highly sophisticated system. Once one admits
that it must have taken many millions of years to
evolve, it becomes impossible to deny that it
must have happened long before mammals
had even properly separated out into the
species that they are today.
The only difference between a human and a
cat in the matter of pain perception, as I mentioned
in a previous post, is the "rationalization" of it,
or the thoughts that we superimpose upon the
experience that can then heighten or suppress
the fear or discomfort that goes along with it.
We can make pain much more fearful for
ourselves if we are psychologically conditioned
to do so, and we can equally make pain much
more manageable for ourselves if we have
the strength and presence of mind for that.
Cats cannot manipulate the experience in
that way, neither for the better nor for the
worse, and furthermore, they cannot have
the understanding that time limits most
pain in the end and so can have no way
to mitigate the terror that comes with
not knowing if the pain will ever stop.
--tension