In article <2ud5e4$aiu at mserv1.dl.ac.uk>, TOMASI at MVCHSS.CINECA.IT wrote:
> In human physiology, pain is described as "an _unpleasant_ sensation that is
> elicited by strong tactile, thermal or other stimuli".
How do you test whether an invertebrate is feeling pleasant or unpleasant?
It isn't testable, therefore, no conclusions can be drawn either supporting
refuting the hypothesis that an invert feels unpleasant.
> Pain has two components:
> a neurogenic (thalamic) and a psychic (cortical) one. Only the cortical compo-
> nent is conscious, discriminant, and can be reasoned upon.
Yes, this is true in humans.
> Of course, inverte-
> brates lacking a cortex cannot have this second component,
Where is your evidence to draw this conclusion? What if inverts have a
center in their gagnlia that allow for consciously feeling unpleasant?
I can not claim that inverts have the capacity to feel unpleasant, you can
argue that they do not have the capacity to feel unpleasant. Evidence does
exist that supports or refutes either statement because it is not testable.
> Since the
> operation disconnects the cortex from the lower (thalamic) centers, we might
> finally assume that "pain" as we mean it (i.e. an unpleasant sensation) cannot
> exist without a fully functional cortex.
In humans that is a valid conclusion. However, this is not testable in
because you can't ask an invert if they are feeling unpleasant. Therefore,
your assumption lacks evidence.
> The fact that a withdraw reflex or
> even memory can be present without a cortex does not prove that the animal
> feels pain:
This is quite true, and I should never have tried to draw the conclusion
inverts feel pain.
> On the other hand, as someone has argued in a previous posting, we will never
> know what the lobster thinks of all this... :-)
This is very true, and the reason why no conclusion can be drawn either
supporting or refuting the hypothesis that a lobster feels pain.
jstream at girch1.med.uth.tmc.edu