Posted by Tyler on December 27, 1996 at 08:22:58:
Here I shall set forth what I believe to be a sensible argument against the possibility of an afterlife; a tenet that is so central to most/all religions.
First we need to clarify the sense as to what constitutes a person. The historical view has been that there are two substances; the body and the soul. Each lasts from day-to- day. The difference between them is that though the body will cease to exist at some point, the soul transcends temporal limitations. The part of this thinking which concerns the present life is most certainly false. The body of now is not the same body of an hour ago, primarily due to the constant cycle of nutriment and wastage. Also we now understand that matter and energy interchange, thus it is no longer sensible to say that the SAME atoms that constitute a person will always be so. Thus, I'll assert that the body has continuity only through the rough approximation of appearance and behaviour.
Similarly with the mind. Although we think, feel and act there is no evidence of a bare entity which experiences those things. By entity, I mean that which may be localized. Ever try to locate, in space, thoughts? Temporal considerations seem to be a problem as well due to memory, shared experience, etc. I'd say that a person's mental continuity is a collection of habit and memory. If you think about yourself yesterday, what you are really doing is recalling certain mental occurrences, which are now remembered as part of the person who now exists. All that constitutes a person are experiences connected by memory, and by those experiences which are similar enough to one another that we call them habit.
If we are to believe that one survives their own death, we are forced to conclude that the memories and habits follow the person into the new set of occurrences after death. (in religions that do not teach rebirth or reincarnation). Since the brain, presumably the source of what we call thought, disintegrates at death, the electrochemical processes also must cease and therefore the thought and memory too. All memory and thought is easily recognized in certain cerebral structures, yet not in others. Our mental personality is thus tied to the health of the physical structures of the brain.
Now we all can pretty much agree that a person's state may be altered through electrical, chemical, or physical intervention. Memory can be obliterated by an injury to the brain, a saintly person can be made mad by encephalitis, and an astute child turned into an idiot from iodine deficiency. It therefore seems very improbable that the person/mind can survive the total destruction of the brain and its structures.
This is a VERY short summation of several arguments but, as always, I am interested in hearing other opinions!