This fictional substance, coincidentally, has many similar characteristics as the atom bomb. Chiefly, they are both symbols of the destructive power of human technology run amok (Peacock vol.44 210). They also highlight humans' flaws, showing that we are too careless to be responsible for anything as dangerous as ice-nine or the atom bomb. Vonnegut exaggerates this carelessness by giving immediate ownership of ice-nine to the three obviously irresponsible children of Dr. Hoenikker (Student Resource Center 1). Ultimately, Vonnegut uses ice-nine to demonstrate the fundamentally destructive nature of humans (Bloom 40). The novel ends with the complete destruction of the world, showing Vonnegut's interpretation of nuclear holocaust (Vonnegut 191). In all these ways, ice-nine is almost synonymous with the atom bomb.
Hoenikker can be seen as representational of our entire race. He is a scientist and inventor on a search for knowledge, just as we are a race on a search for knowledge. It is apparent that this search often yields negative results, as in the child and stove example. Though Hoenikker may be responsible for the atom bomb and ice-nine, he emerges not as a monster or villain but as a giant child (Kennard 1). Hoenikker was actually largely based on a man Kurt Vonnegut knew named Irving Langmuir:
A man that my brother worked with a Nobel Prize winner named Irving Langmuir, was more or less the model for Dr. Felix Hoenikker. Langmuir was absolutely indifferent to the uses that might be made of the truths he dug out of the rock and handed out to whomever was around. But any truth he found was beautiful in its own right, and he didn't give a damn who got it next (Peacock vol.6 208).
That is to say that Hoenikker cared not about what his discoveries were used for, only that he kept making discoveries and furthering his knowledge. This is just part of the strangeness of Hoenikker; he always seems to look at matters from a different perspective than everyone else (Vonnegut 46). It is possibly this skewed perspective that causes him to care so little about the effects his discoveries can have.
Vonnegut uses imagery of the cat's cradle string game in clever ways. The X's that are clearly described as part of the cradle can be understood to represent negation and destruction (Student Resource Center 1). This is only appropriate considering that Felix Hoenikker was playing with a cat's cradle on the day of the Hiroshima bombing. He plays with it in an attempt to impress his young son, Newt (Vonnegut 17). Newt, however, is unimpressed and points out that there is neither a cat nor a cradle in a cat's cradle, and therefore it is illusory and unreal (Bloom 45). In this sense the cat's cradle can be seen as symbolic...