All is meaningless. Vonnegut does a masterful job creating an exciting story that communicates this point precisely. In this vast abyss of meaninglessness, anything that smacks of truth is actually a lie. Most especially religion, science, & sex. These three topics are woven throughout the story. As for religion, the truth about it comes to us in a poem about the makers of religion:
I want all things
to seem to make some sense,
So we all could be happy, yes,
Instead of tense.
And I made up lies
So that they all fit nice,
And I made this sad world
A par-a-dise. (127)
Truth is the enemy of the people because the truth is terrible (172). The truth is life is short, brutish, and mean as ever, (174) and so religion becomes the one instrument of hope. The only problem with it is that it's all lies.
As for science, Vonnegut sees no salvation here either. He is not fooled by the lofty claims of modern man. Science is not the answer to our problems. He takes pot shots at it throughout the story, and in the end, the advancements of science destroy the world.
Sex is all that is left. A glorious feeling. The mingling of bodies, to create a transcendent burst of joy.
Jonah, the protagonist of the story, had worked hard to find meaning through sex. He marries twice, sleeps with over 50 women, and finds himself pulled to the Island of San Lorenzo in hopes of having an erotic adventure with the lovely Mona. In the end, Jonah gets his wish, wild passionate sex with the girl that was better than all the rest. After all of his efforts to get Mona, he disregards the experience as both repulsive. (266)
This greatest of feelings does not help the gnawing meaninglessness that has so captured Jonah. All sex does is make babies -- and babies are a lousy idea amid a dark world. Life is beyond understanding. (182) Maturity is a bitter disappointment for which no remedy exists. (198) In the end, the world is destroyed, and the advice given to the survivor is that he thumbs his nose at God and commit suicide.
Vonnegut speaks with God-like certainty that everything is meaningless, but he makes this massive worldview assertion on faith just like everyone else. Vonnegut's conclusions are not only depressing, but they are also dangerous. His ideas have consequences for the human race if fully believed. If meaninglessness is the truth than the human is liberated from morality.
I think that since we all are believing a story, we should accept the one that our deepest hearts have always longed for and know is right. There is meaning. There is a purpose. There is a plan. There is a song. There is hope. There is light. There is love. There is God.