But that is mistaken on two points. While it is certainly true that a 3-year-old toddler knows nothing about all the cruelty, thoughtlessness, and evil in the world, how innocent is the toddler? That child has already had his share of life experiences of people, in this case his parents, not being dependable for meeting his needs; of knowing that he is not in control of his life, others control it; and experiencing disappointment.
Those three experiences are critical components of everyone's life experiences as they pass through childhood, adolescence, and adulthood. So the child is not this innocent baby that we imagine.
However, as we know from all the smiling, radiant toddlers we have seen, and taken joy in their radiance, those experiences have not yet impacted them; have not dragged them down to "reality."
The reason is two-fold. First, the ego doesn't develop until age 2 or 3, so all the experiences the child has up to that point have not been categorized, labeled, and stored by the mind. The child just experiences this as they are in the moment, much like the chickens in my post, "The Wisdom of Chickens."
Second, because the ego has not developed, it does not supersede the light and faith he was born with. And so the child is still in touch with his Buddha nature, his divine essence, Ergo his radiant smile.
I was right on all counts when the image of my smiling toddler came to me years ago in a meditation and I knew right then that it was the avatar of my true Buddha nature. I am strengthened in my awareness of Buddha nature inside me, of its love, and the power of turning my will and my life over to the care of my true Buddha nature, of surrendering my ego to its care. I am relieved of all burdens caused by the mind.