How to justify your rebellion.

The irony of logic is that it leads to illogic. Logic, when applied to the unknown, leads inevitably to skepticism. Skepticism followed to its ultimate conclusion with sincere honesty about what is known leads to the realization that nothing is actually known. Descartes argued that thinking was being. Nietzsche said "what is thinking?"
Without even the presumption of selfhood as a basis to build on there is no proof of anything. All our information comes either from the physical world through the senses, which cannot be trusted, or through the intuitive and imaginative powers of the mind which cannot be tested.
So skepticism leads to the conclusion that not only does nobody know anything in any absolute sense but that nobody can know anything. Without that essential foundation of knowing we are left at the mercy of faith. Indeed faith becomes the foundation of all belief even that of science. We don't know that we have free will or that the universe holds any purpose and so all beliefs and conceptions of the universe become a matter of faith.
The justification of actions made so often in the last century that 'we know better than them' is complete nonsense. No one knows anything so all knowing is equal. Still...you have to do something or you might as well just lay in bed and rot.
So create a view of the universe that makes sense to you and set aside the fact that you are a completely ignorant and indeed unproven entity and just get on with living a bit eh?