In order to function properly as sophisticated biological organisms, we need motivation.
Inasmuch as humans have developed consciousness, our motivation depends not just on instincts but on cognition as well.
As far as motivation is concerned, non-human animals function effectively when driven by their instincts for survival and reproduction.
As humans have developed greater consciousness, the more we question, “Why do we live?” and “What is death?”
Cognition is a psychological and philosophical concept closely related to consciousness. While self-consciousness is the state of being aware of oneself, accurate self-knowledge involves having a realistic understanding of oneself.
Individuals with extreme religious beliefs possess self-consciousness; they clearly have reflective ideas about themselves and their position in the universe. However, from a scientific perspective, some of their claims about the natural world are factually incorrect.
Inasmuch as we understand that religions are human constructs, and that we are the result of biological evolution, our culture and knowledge have evolved enormously over the past few hundred years.
Because of our cultural achievements in explaining the world and our origins, humans have developed cultural and technological capabilities far beyond what our ancestors of just 20 generations ago possessed.
Our advanced cognitive capabilities suggest one thing (whether individual members of the species understand this or not): anytime we are not preoccupied with tasks of survival, we pursue matters of reproduction, much like other animals.
From a strictly biological reductionist perspective, reproductive behavior is the primary endeavor synchronized with evolution. Some argue this is the only activity providing inherent biological "meaning," viewing constructs like religion, ethics, and morals as human inventions rather than objective realities.
Are you still with me?
We live our lives because we have been born (certainly not by our own choosing). From a strictly biological reductionist perspective, some argue that the only inherent drive available to us is to pursue reproduction and satisfaction consciously, and to hope to end it all with a gentle, unconscious death. Nothing remains.