According to a decades-old study, 92% of infants suck their thumb. Besides all of the normal physiological reasons, I think I’ve stumbled upon another reason for a baby’s fascination and attachment to that particular finger.
In the Sanctuary (and later in the Temple) there is a ritual performed to purify a recovered “leper”, metzora in Hebrew, though leper is a poor but common translation of what is considered a spiritual ailment that displays itself physically upon the skin. Part of the ritual was to take the blood of a sacrificed sheep and place it on the right earlobe, right thumb and right big toe of the healed “leper”.
Ibn Ezra on Leviticus 14:14 wonders what’s so special about the thumb. He then goes on to explain that the thumb is none other than the nexus of the physical and the spiritual. The thumb (think opposable) is what allows man to convert his spiritual desires into concrete action. If it weren’t for our (opposable) thumbs, we would be hard pressed to make and wield tools, to write, to craft or to do most things that humans have developed over millennia.
A child sucking his thumb may be doing much more than seeking comfort and pleasure. He may very well be retaining his connection to the spiritual world, seeking the power of the nexus of body and soul, the most physical part of the body that differentiates man from other primates, the most important digit of the hand.
I will never look at a child sucking their thumb the same way again.
To my nieces and nephews of thumb-sucking age. May you always retain your connection to the spiritual.