Abdu’l Baha contrasted the material body which is composed of atoms and subject to decomposition with the soul which being a simplex is eternal.
“The whole physical creation is perishable. These material bodies are composed of atoms; when these atoms begin to separate decomposition sets in, then comes what we call death. This composition of atoms, which constitutes the body or mortal element of any created being, is temporary. When the power of attraction, which holds these atoms together, is withdrawn, the body, as such, ceases to exist. With the soul it is different. The soul is not a combination of elements, it is not composed of many atoms, it is of one indivisible substance and therefore eternal. It is entirely out of the order of the physical creation; it is immortal! Scientific philosophy has demonstrated that a simple element (‘simple’ meaning ‘not composed’) is indestructible, eternal. The soul, not being a composition of elements, is, in character, as a simple element, and therefore cannot cease to exist. The soul, being of that one indivisible substance, can suffer neither disintegration nor destruction, therefore there is no reason for its coming to an end”.