Vern5 said:
I want someone to prove to me that life has a purpose, a higher meaning, using only logical reasoning. You are not allowed to use any emotional or moral appeals or evidence. Use only logical reasons to prove that there is a point to living.
One assumption that I'm throwing out the window, there is not ONE meaning to life much as there is not a ONE need for a lifeform (Maslow and all that).
Emotional and moral satisfaction (knowing you are doing the right thing and feeling that things are right in the world) necessitates any decent QUALITY of life which must be associated with its meaning. To consider that we can fulfill our meaning without quality would mean refusing to separate "subjects" (conscious beings) and "objects" (non-conscious beings) which is a grave mistake. The meaning of life for a human must be different qualitatively than the meaning of life for a spork.
So taking these three basic premises goes like this (egotism): Humans are conscious beings. As conscious beings we have various needs that require fulfillment biologically and existentially. That means that the fulfillment of our needs IS our meaning, which includes the Prime Directive of reproduction but also includes self-actualization (which includes the emotional and moral aspects of a subject's reality). To use backwards logic, why would we have needs that do not require fulfillment (consider that this only works when not talking about self-destructive needs, which necessarily require some needs to be ignored due to self-destruction. A serial killer may NEED to kill, but that killing removes their ability to fulfill self-actualization and mental/emotional wellness)
Another possibility goes likewise (existentialist): Humans are conscious beings. Conscious beings, by definition, are existentially different from objects for creating meaning in the world. As such, if an object's meaning is to due its duty (a knife cuts), so a subject's meaning is to do what itself is made for (creating meaning). As such, the meaning of life is to create meaning for things and actions.
Another possibility (altruism): Humans are social beings. All of our actions are not about personal reproduction/need fulfillment but the success of the group as a whole (this includes morality and emotional responses, as what use are they otherwise and why would we have them otherwise?). As such, the meaning of a human life is to help the human species survive both through personal need fulfillment (as explained before) but more importantly in the need fulfillment of others.
So those are my attempts, I'm sure you can rip them a part but deciding a "why" with logic is difficult and philosophy is meant to be dissected.