JMagasin Bioethics Discussion Section 8
Happy Thanksgiving!
Deductive arguments review
See Weston (ch. VI) for more info and for some extended arguments
broken down into the basic forms below.
modus ponens
If 'p' then 'q.' If something is made of gold, then it's a time machine.
'p.' The ring is gold.
Therefore, 'q.' Therefore the ring is a time machine.
Is the example valid (structurally correct)? Sound (true in this world)?
modus tollens
If 'p' then 'q.' If it rained, then the grass is wet.
Not 'q.' The grass is not wet.
Therefore, not 'p.' Therefore, it did not rain.
Note that 'not p' does not imply 'not q.' I.e. the "converse"
need not hold since other things may cause 'q.'
hypothetical syllogism
If 'p' then 'q.' If it rained, then the grass is wet.
If 'q' then 'r.' If the grass is wet, then we should not
turn on the sprinklers.
Therefore, if 'p' then 'r.' If it rained, then we should not turn
on the sprinklers.
disjunctive syllogism
Either 'p' or 'q.' Either we'll have chicken or turkey.
Not 'p.' We can't have chicken on Thanksgiving.
Therefore, 'q.' Therefore, we'll have turkey.
Does it matter if or means 'p or q but not both?' (No.)
dilemma
Either 'p' or 'q.' Either the iocaine powder is in my goblet or yours.
If 'p' then 'r.' If mine, then I cannot drink the wine in front of me.
If 'q' then 's.' If yours, then I cannot drink the wine in front of you.
Therefore, either 'r' or 's.' Therefore, either I cannot drink the wine in front of
me or I cannot drink the wine in front of you.
Is this argument valid? Is this argument sound? :)
Practice
The following statements sound somewhat reasonable. However, to
really understand them and to check for assumptions (unstated
premises), it is insightful to give them a more formal structure using
the deductive forms above.
Your task: For the statements below, flesh out the argument to make
it valid. Figure out what premises are missing, and turn the
statement into a formal argument using the deductive forms above.
Sub-arguments are fine, and you may want to use several of the above forms.
- Golden Rice has elevated vitamin A levels. Since vitamin A
deficiency leads to terrible health issues such as blindness, we
ought to help developing countries combat vitamin A deficiency
with Golden Rice.
- Proper informed consent for advanced cancer patients considering
participation in a clinical trial should require guidance from an
attorney not related to the patient-subject.
- Animal caretakers should be integrated into research labs because
they are obligated to protect animals because of their expertise.
- Forced inoculations of military personnel against biological agents
(e.g., anthrax) is ethical because, unlike civilians, they don't
have a choice.
More practice, and for discussion
The following excerpts are from from the Lawrence J. Nelson
required reading. Try to lay out the formal structure as above.
- Embryos are morally considerable in part "because they are valued
... by sincere moral agents whose attributions of moral status
must be given serious consideration as well as some deference and
weight."
Nelson's "principle of evaluative respect and
accomodation."
- "Embryos are in a morally unique relationship with the persons
who deliberately used their gametes to bring them into
existence. For those persons and only those persons,
embryos are genetically a literal part of them and have the
potential to become their children. Consequently, these embryos
have some moral status due to their unique relationship with
the gamete sources."
- "But this potential has moral significance only if the woman
who provided the egg, or some other woman, voluntarily chooses
to gestate the embryo with the consent of both gamete
sources. Embryos do not have moral status simply because they
have theoretical potential to develop into born
persons. Embryos have true potential only if they are in the
process of being gestated by some particular woman."
- "...there are sufficient scientific reasons to believe that
research with stem cells could someday result in significant
benefits for suffering and injured persons. This is a great
moral good; it is not mere caprice or frivolity that underlies
the promise of stem cell research. Therefore, it is ethically
permissible for embryos, which have a modest moral status but not
the status of persons, to be destroyed in the course of
responsible stem cell research -- provided they are
destroyed with a sincere attitude of respect, for there is a
moral loss here -- something morally valuable is being destroyed,
and provided they are used only with the voluntary,
informed consent of both gamete sources."