This is a very broad topic that has been and continues to be pondered and analyzed from many perspectives, including those of art, biology, literature, philosophy, psychology, and religion.
For example, Buddhism teaches that existence is a perpetual cycle of suffering, death, and rebirth from which humans can be liberated via the Noble Eightfold Path.
Meanwhile, many Christians believe that humans are born in a sinful condition and are doomed in the afterlife unless they receive salvation through Jesus Christ.
Two thousand years later René Descartes declared "I think, therefore I am" because he believed the human mind, particularly its faculty of reason, to be the primary determiner of truth; for this he is often credited as the father of modern philosophy.
[5] Charles Darwin established the biological theory of evolution, which posits that the human species is related to all others, living and extinct, and that natural selection is the primary survival factor.