Individual:
Biology .a.a single organism capable of independent existence.
Viability:
b.(of a fetus) having reached such a stage of development as to be capable of living, under normal conditions, outside the uterus.
Just to pre-empt the standard responses:
1. Note that my first definition is in the 'biology' section. As such, it's talking about biological independence, not social/emotional/financial etc. To suggest otherwise would be the case is to suggest that there are very few 'individuals' in this world; clearly this is not the case.
2. Also given the biological nature of the definition, it
doesn't make sense to read 'exist' as simply 'all the atoms would still be present' - for one thing, this could apply to anything, so the phrase would be grammatically redundant and pointless to include in a definition (like defining a wall as 'a structure that is red if it's covered in red paint'). As we are discussing biology, to biologically
exist is
to have life or animation; live..
Again, you are not capable of independent existence either if you want to play semantics...neither is one of the individuals of many pairs of conjoined twins....viability is not a requirement to be either an individual or a human being...it is a pointless point to try to make...anyone on life support is not viable and yet, they are human beings.
A ZEF is not an individual until viability.
Sorry guy, every dependent twin in a pair of conjoined twins proves you wrong...Neither independence nor viability are requirement for being an individual human being.
How long before you trot out all the rest of your failed arguments again? You don't think I remember the answers I gave you before?