Once biological immortality, as in eternal youth, as in endless cellular renewal is developed, because it is a biological process that is developed by the body itself, one realises that the crystalline structure of the human body is subjected to adaptation in every aspect of life. That which usually hinders such development in humans is age old inherited crystalline structures. Such as intellectual structures dictating beliefs and formulating thoughts.
The human body is far more liquid than it is solid, and therefore malleable through directed will. That which is solid of the human body constitutes far less than the malleable structures – yet these minor structures asserts far more control in most humans than their own directed will. It has grown into a crystalline cage of intellect. Yet the very principle of neuroplasticity proves this intellectual cage to be null and completely subject to adaptation and change if proper will is asserted. Few people are masters over their own brains, so much so that they can control its very processes of thought. They are enslaved by their instincts and their beliefs and by so cannot even control their own bodies to a hundred percent capacity.
Endless cellular renewal is not granted through an external medium, it is developed by means of growth. Meaning, immortality in terms of rendering ageing obsolete is grown from within. It cannot be granted through an external medium. Although external mediums can be used in the transmutation and growth of cells. But if the genetic code dictates the life cycle of the cell and cellular structure, no external medium will keep the entity alive.
When biological immortality is developed, which is a tremendously challenging task in and of itself, the next task is even harder. And that is to accept that all those who fail to accomplish it will perish. And that you will be forced to accept a life of loneliness.
Maybe that is why most people fail to accomplish it. Because it is a very hard choice to make.