I think one of the hardest things to wrap your mind around in the Buddha’s teaching is that everything is a process. There are no “things.” A “thing” is just a momentary manifestation of current conditions. In the physical world this equates to sciences like chaos theory and quantum mechanics and the butterfly effect. Everything arises and passes away. Iron rusts and turns into sand. Weather systems change moment by moment. Mountains are moving and wearing down or getting pushed up by tectonic plates. The universe expands and then – poof! – it contracts, there is another big bang, and we start all over again. The body is born, lives, and dies.
In the realms of beings we add to the physical phenomena the aspects of virtue and consciousness. Greater virtue gives us a greater chance of an auspicious rebirth and happier existence. It is not deterministic, but it improves the odds. So that child who dies may have simply been working out a little bad karma, after which he or she attains a higher and happier rebirth. That is quite a radically different way of looking at what might normally considered a tragedy. A true tragedy in Buddhist terms is wasting the opportunity to evolve into a more virtuous person and to practice the Dharma.
Consciousness is where you have any opportunity to train and evolve into a higher being, eventually transcending the realms of rebirth entirely. Some people consider this selfish, but I have a different take from whisperings that I have gotten over the years. The Buddha never talked about what happens when an arahant dies, only that it cannot be described in conventional terms of space and time. What I think may happen is that you become something akin to pure energy, or more specifically, an energy of virtue that permeates all of existence. Your virtue as an arahant benefits all beings. Ayya Khema hinted at this in one of her Dharma talks, and that would a) explain why the Buddha never talked about it (ancient Indians did not have the notion of energy) and b) it would be consistent with the entire path being one of cultivating virtue.
This is also why schools of Buddhism that think you can do an “end run” (Thanissaro Bhikkhu’s words) around the precepts are really flirting with disaster. You cannot be performing acts of sexual misconduct and be practicing the Buddha’s teaching, and you cannot avoid the consequences unless you later repent and take steps to do so. Again, karma is not deterministic, otherwise the serial killer Angulimala would not have been able to become an arahant. But you do have to see the error of your ways and radically change your conduct.
This, then, is the dance of life. Indeed, it is the dance of existence itself.