It is interesting that this subject is being discussed at all.  This suggests
there is, perhaps a "consensus of conjecture."  People are thinking about
this.  I must say that "If right and wrong depends on the social context "
then we are speaking about Moral Relativism and this can be as problematical
as Absolute Morality because, in our history, some regimes have followed this
doctrine, politically shaping the "social Context" to suit there own
objectives thereby dispensing with morality to further their own insatiable
addiction for Power and Domination.
         It has always seemed to me that Moral Relativism is often used to
dispense with values one doesn't like.  Morality, or a standard of ethical
values seem to require more effort and requires more commitment than "to do
whatever is expedient under the circumstances."  That's why this question of
Mollusks having feeling is, in the absence of scientific documentation, a
philosophical question.  Perhaps that is the proper context, because then we
will simply put out this question into the Universal Marketplace of Values
and then, in the final analysis, as with other matters of belief, it becomes
a very personal matter of conscience.  One cannot rightly impose a Universal
Code of Conduct on everyone, but one can offer it as an alternative.
        One reason why this question is compelling is because, I would guess
that all of us are fascinated and "in Love" with Life and enthralled by the
complexity and beauty and wonder of it all.  We appreciate these living
things and already respect them.  They fascinate and delight us.  That is the
reason why we covet them.  We want to keep them nearby so we can admire them
often.  That is also the reason why some of us also feel, simultaneously, a
dislike and an aversion for ending the life of such a remarkable creature.
But we compromise and accept a certain amount of discomfort, in order to
assemble a collection which will add to scientific knowledge, aesthetic
appreciation and foster interest in Mollusks.  Dedicated shell collectors and
conchologists will make this compromise.  Others, who cannot, will turn to
collecting coins or art or to some other pursuit.  Thank You for reading this
far.