Originally posted by lucifershammer
Even if you want to assume (from context) that the UDDA is talking exclusively of human beings, we have:
(1''😉 If (H and (A or B)) then D
It's a relatively simple matter to see that nothing can be inferred about the humanity of the zygote from the UDDA.
As an aside, if the UDDA did actually define what a "dead human being" was (as you fal ...[text shortened]... ficient[/i] condition for being a dead human being. So my dead-cows rebuttal would still stand.
Actually this is a bit of a logical sleight of hand.
If the UDDA is a definition about human beings at all, it is not a definition of
a dead human being but of death
for a human being. The two scenarios in the UDDA might not together provide a necessary and sufficient condition for something to be a dead human being (else we might indeed have to say a dead cow was a dead human being), but they might still provide a necessary and sufficient condition of death in a human being, i.e. define what it means for us to say of a human being that he/she is dead.
It works better if we use quantifiers:
(Ax) (Hx) then (Dx) iff (UDDA1x v UDDA2x).
Roughly: For any x, if x is a human being, then x is dead if and only if x has suffered irreversible cessation of circulatory and respiratory functions, or x has suffered irreversible cessation of the functions of the entire brain, including brain-stem death.
Then it seems you do have a problem classifying a zygote as a human being, and cow-related counter-examples are avoided.
Of course you are right that this assumes that by "individual" the UDDA means "individual human being". And the UDDA should really have an extra sentence saying: "Any individual that hasn't sustained (1) or (2) isn't dead." (Arguably that is implied. I doubt the UDDA was drafted by Frege...)