The theory of a natural eternal consciousness (NEC) states that human consciousness is not extinguished with death but merely paused. That is, the last conscious moment of one’s last experience becomes imperceptibly timeless and deceptively eternal from their perspective. Moreover, if that experience is a vision, dream, or near-death experience (NDE) and is perceived as an afterlife, then the NEC is a natural afterlife. An earlier article by this author explains the NEC theory and claims its validity. This addendum provides (...) a brief overview of that article but, more significantly, these enhancements: (1) an easier to grasp description of the notation used to formally define the NEC and natural afterlife; (2) an extension to this notation to formally define the eventually timeless natural afterlife (etna) — a time-perceiving, activity-filled afterlife that concludes with the timeless natural afterlife and can provide optimal eternal happiness; (3) more focus on the validity of the NEC theory: the role of self-awareness, the theory of Paused Consciousness in Timelessness (PCT) and its everyday verification, and the improbable falsification of the NEC theory as a hypothesis to the PCT theory; and (4) a new diagram that summarizes the meanings of NEC-related terms and the relationships among them. (shrink)