The sciences, both natural and human, are arguably the most objective areas of knowledge as they deal more in fact and observation, as opposed to the more opinionated and inference-based subjective areas of knowledge like faith and ethics. Before we delve deeper into how the sciences give us a better grasp of ourselves, we must first find out why mankind began asking such existential questions in the first place. Though the human race has existed roughly for the past 250,000 years, we had only began developing intellectually after the Neolithic Agricultural Revolution which took place around 12,000 years ago during the Stone Age. It is during this time period that man learned to farm and raise livestock, evidently saving time and energy, allowing for contemplation and recreational activities. This newly acquired method of food production allowed these early beings to live easier as survival was no longer a burden. This period was a turning point when man no longer asked himself the question "how will I survive today", and began asking the question "how shall I spend my time".
Based on 19th century philosopher Søren Kierkegaard's Existentialist Theories, the most common way individuals seek to find self-understanding and purpose is to find their role in society. This would later on involve homogenizing with other individuals to form a social jigsaw puzzle, if you will, of varying shapes and sizes. Later existentialist thinkers widened this range of co-existence to further include nature and our planet. This is where natural science fits into the big picture. Where we fit and who we are in society corresponds to what we can offer the larger group. Natural science answers the question of who we are physically, and what we can do with our physical appendages and capabilities.
One field of natural science, Physiology, dates back to 420 BC and is the study of function in living systems.