I believe that everything is a state of mind/state of intelligence. The state of mind can be in these possible states: negative, positive, both positive and negative, but never neither. The state of intelligence is the level at which the mind is capable of preserving a worthwhile state of mind/being/thinking(eg. preservation of health, livelihood, culture). If the mind is aggressive enough, it would invade/stake new "territories", spreading its belief system(for example, personal beliefs, propaganda, cultural imperialism).
I have never heard of a person not wanting the good life or pursuing something worthwhile for themselves, otherwise they are mentally sick or something like this. It is normal to look after oneself/keep healthy, develop oneself, or is capable in someway before being able to help others out. What is the goal of the individual; what is the goal of society/humankind? Which is better/more virtuous, individualism or the development/betterment of society as a whole? Which comes first?
All human beings are similar in some ways, spiritually, mentally and physically; but we are separated by our mental "walls"(for example, ignorance) , ego/individuality, prejudices, physical space, etc. If humankind was truly united mentally, then a person a thousand miles away from another person feeling displeasure will feel the same emotion. I think if everyone has this unique ability we would have more empathy.
If the mind was truly united ignorance would be eliminated. If one were to believe sentience is present one would also presume that it is united in some way, by God or other way such as psychic abilities. It is a paradox if two people share their humanity in common, yet their personality is so dissimilar. When can two human beings become so different in personality over time they can be called two different species?
thanks for reading.
You're asking questions that cover the whole of philosophy. It's impossible to give you a complete answer; no current philosopher could.
The notion that everything is conscious or intelligent in some sense has moved in and out of philosophical responsibility since philosophy started, and is undergoing a bit of a revival now (latest example: Thomas Nagel's book, "Mind and Cosmos", in which he argues that the human could not have arisen through Darwinian evolution but must represent a concentration of the intelligence present in the universe as a whole.
Regarding your first paragraph; why don't positive AND negative sum to neither? Can one be just a little bit positive or a little bit negative? Second, what's the evidence? WHY do you believe this? What would you say to convince someone else?
Regarding you second paragraph: a rational being has always been defined as one that seeks its own good. Rationality alone can provide a basis for altruism (see any book on game theory.)
Regarding the third paragraph. You're right that if we had more insight we would have more empathy, but you seem to think that we can have the same thoughts and personality and still somehow be individuals. Hard to do.
Regarding your fourth paragraph, differences in personality are clearly a result of both nature and nurture -- genes and life experience. For us all to turn out the same, we would all have to have the same genes and the same experiences. Hard to do.
Hope this helps.