Why RedRace and BlueRace hate one another
- There used to be one race (OriginalRace)
- Cloning technology turned this into two highly similar races (OriginalRace and CloneRace), but which is which is lost to history
- That's it, that's the whole reason they hate each other.
Being a Clone Sucks
For a take on the individual version of this problem: Cloning Blues (TVTropes)
There are many variants (evidenced by the TVTropes examples) but the basic premise is that the knowledge that one is a clone can lead to a wide range of psychological issues dealing with the ensuing identity crisis.
Being a Clone Sucks -- Uncertainty Edition
One of my favorite takes on this is when the cloning process somehow leaves doubt as to which individual is the original and which is the clone. Each wants to believe that they are the original (without evidence suggesting it), mostly to side-step all the nasty implications of being a clone.
However confident an individual may appear, the nagging doubt that they may not be real is always in the back of their mind, and unlike their "definitely a clone" counterparts, it's unlikely they'll be able to accept and get over it.
Why Uncertain Clones Hate Each Other
This also naturally leads to negative emotions between potential clone counterparts. Let's assume the following axioms and see what follows:
- I want to prove that I am real
- Only one of us is real
(2) directly implies (3)
- Any evidence supporting the hypothesis that I am real also supports the hypothesis that he is fake
It's easy to rewrite (1) and (3) to:
- I want to prove that he is fake
(4) From rewritten my counterpart's perspective:
- He wants to prove that I am fake
(1) and (5) are directly at odds. We have a source of conflict. We can both be rational, and we can both be ethical, but as long as our desires are mutually exclusive we will find ourselves on the opposite sides of things quite often, and that can bleed through.
If we add the following assumption:
- clones are commonly expected to be inferior in some way to the original (more susceptible to disease, not quite as strong, not quite as smart, etc.)
there are a few more consequences:
- any time I outperform my counterpart, I'm relieved and happy: This is evidence that I am real and my counterpart is fake. This could even lead to pity, which may be resented by my counterpart.
And it's corollary
- Any time my counterpart outperforms me, I'm forced to confront the possibility that I might be fake again. This is unpleasant and uncomfortable. This always occurs just as my counterpart is experiencing the comfort and joy that comes from being secure in his reality.
A pattern emerges where my happiness is correlated negatively to my counterpart's happiness. The strength of the correlation could be strong or weak depending on just how much our sense of identity is important to us vs. our other sources of happiness, but it will always be negative.
Making it Societal
Possible Origin Story:
RedRace created Clones for slave labor. They ensured that they could not reproduce with an Original to prevent the nasty question of what rights should go to individuals born to one RedRace and one Clone parent, but otherwise left the genome as unaltered as possible, so they could easily be a drop-in replacement for Originals in every sector of the economy (even traits like inbuilt servitude might prevent them from functioning in some roles or functions). Clones, as a result of the slight genomic alteration, also ended up with Blue Skin, and were thus dubbed BlueRace. BlueRace didn't like the current world order, revolted, and during the war captured and deleted all records which proved RedRace was the OriginalRace, and started an intensive propaganda campaign claiming that BlueRace was the OriginalRace. Hundreds of years after the end of the war, no one alive knows the truth for certain. Almost everyone agrees that regardless of the truth, both OriginalRace and CloneRace individuals have the same set of rights and responsibilities, and should be treated as equals. Despite nominally open borders, it's far more comfortable to avoid being reminded that someone is fake (especially without members of your own race near you to back you up) by going into OtherRace territory and interacting with members of OtherRace.
Societal achievements could take the place of personal achievements for purposes of determining which is real, spurring advances in technology, governmental systems, or ethics.
Individual achievements may still be seen as supporting evidence for one race's superiority, especially among the less "enlightened" members of the species. Sports and other competitions would be extremely tense for these reasons, especially any sport which involves referees for scoring or rule enforcement like gymnastics or even football.
Any achievements made by RedRace will be attributed to luck, foul play, or just "not being that important" by BlueRace, while they will emphasize any area where they are outperforming RedRace.
Bonus Round
If religion teaches that only "God's creations" have a soul and get to enjoy the afterlife, being real has much stronger implications and the tension goes up a lot, even if both races follow the same religion, and even if the religion preaches tolerance and love for every living creature, clones included!
RedRace zealots could word tirelessly and donate all wordly goods towards helping BlueRace people live comfortable and fulfilling lives, on the premise that they have the entire afterlife to enjoy themselves, BlueRace only has their 80(?) year life. They legitimately practice love, compassion, and self-sacrifice, but it's rooted in the assumption that RedRace is real and BlueRace is fake (and somehow inferior) so it ends up being divisive all the same.