How is the "second childishness" in "The seven ages of a man" related to being a child?"The seven stages of a man" from William Shakespeare's "As You Like It"
In the monologue of Jaques from Shakespeare's "As You Like It," the borther to Orlando capitalizes on the words of Duke Senior who states that "we are not all alone unhappy...in this wide and universal theatre." Jaques calls the world a stage upon which men and women are players, making their entrances and exits. In the first stage, the infant is "mewling and puking in his nurse's arms." Finally, in the seventh stage, man has returned to the infantile stage as he exists in "mere oblivion" and is "sans"/without teeth, without sight, without taste, without everything. Like babies who have yet to reach the development of their senses, the aged have their senses mitigated to a similar point, but it is the loss rather than the nascence as in infants.
In this poem, Shakespeare uses the phrase "second childishness" to refer to the way people are when they get old. This used to be a very common euphemism for senility -- for the way that some people end up when they become old.
Some old people end up more or less like children. They have less control over their emotions and are less inhibited. This makes them act like children. In extreme cases, they lose control of their bodies and need people to help them get dressed, wash themselves, etc.
Because some old people end up this way, the term is often used (not as much today) as a way of referring to old age.
A child, coming in this colorful world cries and vomits milk in the arms of nurses. At this stage they are teethless, tasteless, visionless and awaits tasting, seeing and smelling the colorful matters of this sweet world. Similarly, reaching at the old age a man becomes again teethless, tasteless and visionless. Then he awaits just to hear the call from Almighty.