Aristotle's concept about the soul, being the cause and the first principle of the living body, is also common to all monotheistic religions with little divergence. Despite significant differences on other points, these religions share common views about the moral importance of soul and ensoulment. Aristotle's argument of 'the soul is the cause and the first principle of the living body' should not be dismissed as a religious myth. Something is lacking in all our reflections on the subject if we take into account only the material existence of living beings. Although life is a continuous process, the physical existence of living beings is finite.
Some cells live a couple of hours, others live a couple of days, weeks or months.
After that they die and are shed. It is now known as an incontrovertible fact that, with the exception of some brain cells, almost all the cells in a human body are replaced with new cells every two years. Thus, in two years time, as regards my physical and material existence, I will be a completely different being from one I am today. This defense is logical and acceptable if I am only a material being. It is possible to consider this analogy comparing with wooden ship example, that is cited in Parfit's book, in which the wooden ship is repaired from time to time while it is floating in harbour, and that after 50 years it contains none of the bits of wood out of which it was first built.