  Despite the success of modern physics in formulating mathematical theories
that can predict the outcome of experiments, we have made remarkably little
progress towards answering the most fundamental question of: why is there a
universe at all, as opposed to nothingness? In this paper, it is shown that
this seemingly mind-boggling question has a simple logical answer if we accept
that existence in the universe is nothing more than mathematical existence
relative to the axioms of our universe. This premise is not baseless; it is
shown here that there are indeed several independent strong logical arguments
for why we should believe that mathematical existence is the only kind of
existence. Moreover, it is shown that, under this premise, the answers to many
other puzzling questions about our universe come almost immediately. Among
these questions are: why is the universe apparently fine-tuned to be able to
support life? Why are the laws of physics so elegant? Why do we have three
dimensions of space and one of time, with approximate locality and causality at
macroscopic scales? How can the universe be non-local and non-causal at the
quantum scale? How can the laws of quantum mechanics rely on true randomness?
