Slaves to motion, change, and progress
Mr. Zero is zero -- there is no substance, simply a man striving his whole life for happiness and opportunity ...
Shanelle made an interesting point here and really gave me something to think about.
If Mr. Zero truly is a flat character, as some of my classmates have argued, then perhaps Rice made him so in order to point out that his quest "for happiness and opportunity" only leads him into an endless cycle that will always leave him wanting more.
In America, the "pursuit of happiness" is one of our founding traditions, but we go about it the wrong way. We marry and we work hard and we buy, buy, buy, all in the hopes of a better life in the end, and I think Rice was trying to imply that this will never lead us to true happiness. If we live only for the end result, only take advantage of opportunities for the sake of the final product, then our lives have "no substance," and remain static. A man like Mr. Zero could accomplish every last one of the dreams he has today, but he still wouldn't be happy, because tomorrow he would have different dreams and goals -- a fact alluded to in the play when Mr. Zero finds out that he's headed for another round of life on earth, as a completely different person. No matter how high up the ladder we climb for ourselves, we can never reach the top. We can't even get close -- it's reserved for God.
When Charles tells Mr. Zero that he is a "slave," he means, more than anything, that he is a slave to himself. He means to say that in striving to make our lives easier -- to create machines that further and further simplify our tasks -- we are actually driving ourselves to ruin. What would happen, after all, if we were to reach that point described in the story, the epitome of human civilization, at which everything is accomplished with the mere press of a button? We would hate it, we would despise it, we would be miserable -- because we would have nowhere to go, no more progress to make. Human beings thrive on constant motion and change that takes them closer to a certain attainable goal or ideal, thus explaining why Shrdlu is so disturbed by Rice's Elysian Fields -- they do not foster growth or change with an end-purpose, only endless repetition of "profitless occupations," as he puts it.
If there were one lesson to be learned from this play, I think it is probably that the pursuit of happiness itself should make us happy, that we should find fulfillment in the journey rather than the destination.