Reincarnation is real; just not in the way Buddhists or Hindus put forward. It is real on a secular, materialist level. If an arbitrary subset of the universe’s matter can fall into a configuration allowing for a self-aware feedback loop known as consciousness (this configuration is usually a brain, in our experience), and this self-aware feedback loop continues until death, then that means the very same arbitrary subset of matter can fall into that configuration again. However it is difficult to keep track of that arbitrary subset of matter once it disperses and recycles through the environment after its conscious configuration decays (“dies”). Furthermore, each “atom” is not indivisible, but is made of subatomic particles, which themselves have differentiated components, some discovered, some still undiscovered.
The specifics of our universe are not so important. Leave that to the physicists. What’s important for the purposes of this discussion is that matter has a dual nature. Any given material can be described both as distinct (specific, particular) entities which are the sum of their constituent parts and non-distinct (vague, non-particular) entities which are mere fluctuations in a field. This shows that everything which can be described according to its observable physical characteristics and constituent components is subject to the “Ship of Theseus” paradox. I will not describe that paradox because most are familiar with it. It is widely discussed. Moving on: If a brain decays and dies, its component material disperses into the environment. But eventually, on a long-enough time line, a brain made of the same material could re-emerge as a new conscious configuration. However, none of the “memories” of the “past life” would be in-tact. Moreover, there is no metaphysical “karma” system in place. It is entirely random and chance-based. This is quite frightening, because it means that “you” could “come back” as someone with a much more miserable and painful life than you, and there would be nothing “you” could do in this life to prevent this from happening to “you.” This is all very dissatisfying, but there you have it. Secular reincarnation.
The possibility of becoming conscious again in the future, as a different creature, in a different life, puts forward a strong individualist argument in favor of instituting some kind of collective social change to make the average or median life much less miserable. An argument in favor of socialism. No longer are you merely fighting to save future generations, who you will never live to see, from the pain and misery of capitalism. You are fighting to save “you,” in a future life, when “you” “come back.” A doctrine of secular materialist reincarnation, based on the self-aware feedback loop (consciousness) generated in arbitrary, self-aware, configurations of physical matter, therefore can inform scientific socialism by providing an incentive that goes beyond our current lives, and beyond even our own class interests, since, after all, an individual who is bourgeois now may reincarnate as a prole in the future. It also provides an alternative to afterlife doctrines put forward by the organized Abrahamic religions, which hold that the world is merely an illusion, and our real life begins after we die, and our entire life should be dedicated not towards improving the world, but to serving God, and accepting the world for the cruel simulation that it is. A doctrine of secular reincarnation can wed itself to Marxism, and overcome the incentives provided both by Western and Eastern religions, while not at all contradicting historical materialism. After all, if you are conscious now, you can become conscious again, even if you have no memory of your past life, you still suffered through it, and could potentially live future lives as well. This is all the incentive one needs to improve the world, since the world is what gives rise to consciousness. Rather than an immortal “soul” that goes beyond matter, you have simply your material self, which is a subset of the physical universe, and a strong incentive to improve the physical universe towards making life less miserable for your self and your peers, who are stuck in the same situation as you.
This all might sound spooky, anti-materialist, religious, or idealist, but I assure you it is none of those things. It does not in any way contradict what we already know. After all, if a brain becomes damaged, there are observable changes in behavior and personality. Therefore the material basis of consciousness is established. If consciousness comes and goes with self-aware configurations of matter, and such configurations of matter arise from “dead” configurations, then rebirth is demonstrable. It is based not upon the “soul” which is unfalsifiable, and non-material, but upon the characteristics of matter itself, which are not yet fully understood, but nevertheless observable. Having reservations about all this is understandable, but I think there’s a strong incentive to move towards a doctrine of secular reincarnation, both as an incentive towards socialism, and as an incentive away from short-term avarice. Capital’s strangehold over our global economy is largely based on the perverse incentive structures it has built upon the foundational assumption that we only live once, and that in our lives we should accumulate, accumulate, accumulate, without any sort of care for what comes after we die. Indeed, the only reason the ancient religions have stayed relevant for so long is because only they are providing an answer against this incentive, it is simply that their answers are anti-materialist. We must provide a materialist alternative. The doctrine of secular reincarnation achieves precisely that.
Marx said that religion is the sigh of the oppressed creature, the opium of the masses. The doctrine of secular reincarnation is the opposite. It is a rallying cry to fight with all your might against capitalism in this life, so that when you are born again in the future, without any choice in the matter, you will perhaps not have to fight against it again. It is a rallying cry to overcome the selfish incentives of the competing doctrines of “You Only Live Once,” “Afterlife,” and “Karma-Based/Soul-Based Reincarnation.”