Originally posted by: CycloWizard
Originally posted by: totalcommand
It's simply logic. Something that has potential to be A cannot be actually A at the same time. For example, you right now you have the potential to be "the person you will be nine months from now" but, right now, you cannot actually be "the person you will be nine months from now". A simpler example is a piece of firewood. Right now it may have the potential to burn, but it cannot actually be burning at the same time. Actuality and Potentiality are mutually exclusive in other words.
I agree. However, the development of any human (or even any animal) is a continuum, not a discrete set of points. Such demarcations are set up (zygote, blastocyst, embryo, fetus, etc...) as a matter of convenience for reference, not because these are truly different organisms. At some point, every person you know was or will be a zygote, then a blastocyst, then an embryo, then a fetus, then an infant, toddler, child, teenager, adult, middle-aged, elderly, old, very old, and ancient (assuming they live that long

). Thus, I could argue (though I'll admit that I haven't thought this through very carefully) that a zygote is just as much a person as an infant, adult, or anyone else. The discretizations that are set up are fabrications based on stages of physical development, not any real change in the being itself. Think of it in these terms. Everything is comprised of two parts: accidentals (physical nature) and substance (whatever it really
is). The substance of a zygote is no different from an adult as far as we can discern (though one might argue that substance changes with time, again I'm not real sure since I'm winging it), though the accidentals are much different.