It was said, "When the living being dies, the consciousness suddenly is disembodied."
There is no entity to be called "the consciousness" that becomes embodied or disembodied. Consciousness (used in the expansive sense that includes the unconscious or Alaya consciousness) is like a great river with many tributaries.
DNA is the materialist version of karma. The complexity of the structure and function of karma is as complex as the structure and function of DNA. That is why Buddha only gave the most simple teachings about karma of the kind "you reap what you sow" or "there is bright karma, dark karma, and mixed karma." These simple formulations of karma are helpful in creating the mental affinity for moral actions.
But to delve into the complex workings of karma can be counter productive by confusing people who have not had the deep experience of no self and then lead them to doubt karma and its efficacy. So Buddha usually would not provide detailed answers to questions about an individual's karma or past lives and only would offer vague or sketchy comments about them.
It was asked, "What is it that is reborn?"
There are two factors that lead to the complexity of thinking about karma. First that there is no self, only a self image, and second that karma doesn't function mechanically like a machine, but organically like life.
Because we find belief in a self that is embodied to be very comforting in the face of uncertainty and the unknown, we create many more or less gross to subtle images of the self to confirm our desire in a self to believe in. Thus we imagine that there is a thing that goes from life to life, something that wears the body like a robe and puts on a new embodiment in a new life like putting on a new robe. Seeking to know what this "something" is becomes the Buddha search and inquiry.
But simply calling it "consciousness" that becomes embodied in the next life is not enough because that kind of "consciousness" just becomes a new self image to hang onto. Hanging on to that kind of self image creates the idea that there is a linear thread of a single chain through many past lives so that a person has one life, then another, then another, in a singular chain. This is a machine view and is not the way karma and rebirth function.
Karma and rebirth function like a great river. An image one should have in mind when considering karma is a map of a great river system like the Amazon, the Mississippi, the Congo, the Nile, or the Yangtze. When we are at any place in the river there are many tributaries that have flowed into the river. Isn't it interesting that where ever any two tributaries come together that only one tributary bears the name of the river? Why is the source of the Mississippi identified as one location and not as the many locations that comprise the source of each of the tributaries? Why is the source of the Missouri river not called the source of the Mississippi? The naming of rivers is a social convention in which the larger of the two tributaries at any point of convergence is considered the main stream of the river and bears the name of the great river while the other tributary gets another name.
Karma is like that also. If we follow our past lives "backward" we imagine there is only one mainstream and call that our chain of past lives, but in fact there are many tributaries of past lives,but our social convention is to ignore those that conflict with our self image of being a singular separate self or soul traveling from life to life. So to give a concrete example, if today we were to ask what was our past life in the year 1658 we would have very many tributaries of actual contributory lives but we would select only one life as the mainstream and call that "my" past life.
Because when people do remember past lives they sometimes do remember several past lives in the same time era, that can cause confusion by challenging the belief system that the self is a separate stream. If someone remembers two past lives in the same time period, that can cause them to doubt the veracity of their memories because we believe in a self and that the self can't be in two places at the same time. That doubt can then lead to a disbelief in or denial of karma, and that can then lead to a nihilistic view that disavows morality altogether. Thus for people who firmly believe in a self, talking too much or too openly about the intricacies of karma becomes counter productive. It is easier to believe in the simplistic self than to try to understand the nuances of the complexities of karma as it relates to the self image in the cream of Consciousness.
Similar patterns for the image of the organicity of the functioning of karma can also be found in the image of a tree with spreading roots and limbs, or in the veins of a single leaf. This non-linearity and non-machine view of karma must be understood if one wants to have a realistic appreciation of how karma and rebirth function.
Some one asked, "Am i to have blind faith that this boy who apparently was a caring good natured boy deserved this to happen because of some action many lifetimes ago?"
Please remember to not confuse the judgemental concept of "deserving" with the observation of "actions" and "results." Asking whether a person "deserves" what happens to them (or any of their circumstances) shows dualistic judgementalism.
For example, none of us knows whether the boy's circumstances were the results of past actions or were innocent uncaused bodhisattva actions. We easily observe that the emotional pain people feel is the result of being human and the functioning of the 5 bundles (skandhas) of our personalities. When apparently "bad things" happen to apparently "innocent" people, we should remember to reserve judgement on the big picture, because we don't know the karmic patterns involved. Of course that doesn't mean that we don't bring the perpetrators to face the judgement of society for their actions, and hopefully the judgement of society will be as compassionate and merciful as it is firm and corrective. (The Sutra of Angulimala is an important koan in this regard.)
Most important, since there was nothing you personally could do, do you know what causes you feel pain in relation to this event you only heard about? Obviously you felt great empathy for the boy and his family. Do you simply take such empathy at face value or do you inquire into it? How much of the pain arises from realizing that the world doesn't conform to our expectations? In other words, did the concept "deserving" arise in your mind or in the world? Before you heard the story you felt one way and then you heard the story and felt differently. Ask and inquire "who feels the pain" using your meditation as your crucible. The conundrum of Buddhism is that we have to let go of our tightly held concepts of "good and evil" in order to see our original face and awaken to the original good.
As I see it, we have to distinguish, on the one hand, the expedient use of the concepts of karma and rebirth used to help us disengage from our habitual models of the world and, on the other hand, the misuse of the concepts of karma and rebirth that turn them into doctrines and even dogmas that only get us more entangled in our habitual models of the world.
We use the self-image, centered on the concepts of "us," "our," "I", "me" and "mine", to make sense out of everything that happens in consciousness and to divide up all things (dharmas) into causes and results. But fundamentally the division of everything that happens into causes and results is arbitrary because each dharma-thing is simultaneously both a cause and result, and the arbitrary division relies on the contextual concepts of time and space that bind us within materialist world views.
In Western Science the concept of "cause and effect" is used to create the temporary illusions of power and control over everything that happens in the framework of time and space, whereas in Buddhism the concept of "cause and result" (karma) is used to transcend the temporary illusions of power and control over everything that happens to realize the unborn suchness that is timeless and spaceless (sunyata).
"I see you oh, Housebuilder, and you shall build no more, the rafters are broken and the ridge beam is shattered." Dhammapada (11:154)
Someone wrote: "Sometimes I think that Karma is misinterpreted. Like we think that when we die something that is in us like a spirit or a essence or anything for that matter is reborn. Also we hear often that some go to heaven and some to hell. If the Buddha said there is no soul then there is obviously nothing that goes to heaven and to hell. Perhaps when he talks of heaven hell and the hungry ghosts etc, he is using allegories for this world."
And another responded, "And if there's no soul or self, i shouldn't be held responsible for actions i did yesterday, last year, or even 10 seconds ago, because that obviously wasn't me. it's party time!"
These kinds of exchanges sadden me, because I would hope that inquirers would have a clearer appreciation of the teaching of karma. But they are also examples of how people may take such simplistic views of karma that they will rationalize their doubts into Nihilistic views such as "It's party time."
It is a basic fact of karma analysis that karma is not about "being held responsible" as if by some supreme being or celestial court of law. This is so in the manner that if you put your hand in a flame you will feel the pain; it is not that something or someone is "holding you responsible" for having put your hand in the flame. If you are in a car and driving toward a cliff, if nothing is done to change course or halt the car, then the car will go over the cliff. That is the karma dynamic: it is not that going over the cliff is being "held responsible" for driving the car in that direction. Same with karma, an action will have a result that the action is directed toward, unless an intervening action will change the course of events. Just karma physics.
Another karma metapohor is gardening. Certain seeds, once planted will sprout and grow and bear the result of what was sown. But if certain events prevent the development of the seed, then the karma of that seed won't be something to reap. But given the fruitful condition of most mind soil, most seeds do sprout, which is why people can't avoid karma simply by ignoring it with wishful thinking that they won't reap what they sow.
Karma is responsibility in the generic sense, in that karma is our ability to respond to our circumstances. We respond with thought, word, and deed, which is our karma. We have formed identities in consciousness, so our responses are in the form of action-intention complexes of mental (and emotional) formations in which the action and intention are inseparable. The coherence of the relations between all our action-intention complexes is what becomes the appearance of our identity or personality, which we then mistake as a "soul" or "self" when in fact there is no underlying "thing" at the core of the onion or the banana tree stalk.
In short, having "a soul" or "a self" has nothing to do with karma, while having a self-image or an identity has everything to do with karma.
The mechanism of rebirth and karma has nothing to do with something "like a spirit or a essence or anything" moving from life to life. Look at a wave in the ocean. It only appears that something is moving through the water. But a boat or a duck on the surface merely goes up and down as the wave passes by, the wave does not move the boat or duck horizontally because the water is not moving horizontally, even though it appears that something is moving horizontally. That is like karma. Each life is like an up and down motion, but over lifetimes there is a horizontal appearance of movement without any "thing" or "essence" actually moving from life to life. The wave is the appearance of an essence moving from life to life, but it is only the dynamics that are "transferred" not a "thing."
The wave dynamics appear in life to life because it is the ocean that is appearing in life to life, the wave dynamics are only an appearance of identity and are not separate from the ocean. There is no identity actually "moving," and no identity existing individually or separate from the ocean. This is why the Diamond Cutter Sutra says though there is the appearance of a living being, and the Bodhisattvas liberate countless living beings, in reality, no living being is liberated.
This is the simplest that I can make it.
People do have past life memories, and that does not mean that consciousness as a thing is transferred, only that the memory arises and falls in the continuum of time and space through the associations of identity. Many people are fooled into thinking because they have a memory of a past life that they "were" that person in the past life. It is not that simple.
In wave dynamics we can observe what are called interference patterns when waves cross each other. This can occur in karmic transmission of identity-waves so that several people can have similar cross-reference points. This is why certain powerful identities seem to resonate with many people who connect to past life memories. It is not always a wish fulfillment, because part of what makes a powerful identity pattern is the way that the karmic-waves have come together in focused conjunction in a wave formation that creates a big-wave identity-formation. When that identity "dies" the wave formations can divide again just as waves in water separate after they have moved through each other in the wave interference pattern.
In my experience, appreciating the wave dynamics of water and light (electromagnetic fields) are the best way to begin to understand how the dynamics of karma function.