Mina and Jetavan, I think you guys are extrapolating way too much from St. Athanaisus's words. The point he is making is that only God is infinite, i.e. having no beginning or end. All creatures are thus contingent upon their Creator, meaning they have at least a beginning. Adam and Eve were created with free will, which made them susceptible to death- not because of their inherent nature but because they possessed the potential to choose sin and thus suffer the consequence of death. I do not see St. Athanasius in any way saying that Adam and Eve were created inherently corruptible, but only that their free will made it possible for corrupution to come to them via their own choice, not by their inherent nature.
St. Athanasius says "they were by nature subject to corruption," not that they were by nature corruptible. This an important distinction. Free will was part of their inherent nature, which made them subject to corruption via the misuse of their volitional will. But St. Athanasius is not saying that they were created corruptible, subject to death apart from sin.
He also makes it clear that the "natural law of death" is the consequential law of the effects of sin. St. Athanasius is not saying that there existed a natural law of death prior to the Fall.
St. Athanasius says that before God bestowed the grace of His own image upon man, man like all animals was "essentially impermanent." Now what does this mean, exactly? Well, we know that only human beings possess the potential for theosis, not animals. So, apart from the grace of having the divine image bestowed upon him - which Scripture indicates happened at the very time of his creation - man would have merely been an animal possessing no potential to attain the deification of which St. Athanasius speaks when he declares, "God became a man in order that man may become God." Thus, this phrase "essentially impermanent" does not automatically imply natural death. For God can create life out of nothing, and thus He can withdraw life without death being involved. Humanity is unique because we have the ability through grace to evolve spiritually and grow into oneness with God while always remaining distinct from God. Animals do not have this privilege, and thus are "essentially impermanent."
I think it is a gross stretch to use the words of St. Athanasius to support the idea of theistic evolution. Do any of us really think that blessed St. Athanasius did not believe in the literal creation of Adam and Eve? Do any of us really think that he believed disease, violence, and death naturally existed prior to the Fall? St. Athanasius would surely tell us that these things were the result of sin, not the natural state of creation prior to sin.