Oliver is a specialist in pre-Socratic philosophy, and the pre-Socratic philosopher Heraclitus is a recurring motif in the work.
"Pre-Socratics" describes a group of philosophers who predated or were contemporary to the Athenian philosopher, Socrates. Socrates is one of the most influential founders of the western philosophical tradition, if not the most influential. Though he himself did not write anything, his pupil, Plato went on to codify his ideas in his own texts, also influencing Plato's own pupil, Aristotle. This lineage of philosophers forms the core of ancient Greek philosophy.
Pre-Socratics focused on questions relating to the natural world, human society, ethics, and religion, seeking explanations based on natural principles rather than the actions of supernatural gods. Pre-Socratics believed that the world operated under a cosmic order which could be understood by means of rational inquiry. Aristotle would later distinguish these philosophers as a new generation of thinkers, departing from their predecessors who attempted explaining the world in terms of gods or divine powers. It is important to note that while several of these philosophers originate from what is now known as the modern state of Greece, they lived in a broader Mediterranean geographical range under the influence of Hellenic (ancient Greek) culture. The term "Pre-Socratic philosophers" also refers to a group of several individual schools of thought who shared similar ideas and were part of a broader trend in Mediterranean philosophy at the time. Among these schools were the Milesian school, the Pythagoreans, the Pluralists, the Atomists, and many others.
Heraclitus himself did not originate from modern mainland Greece but rather from the city of Ephesus, which is in modern-day Turkey and belonged to the Persian empire during Heraclitus's lifetime. Little is known of about his early life, but, being from noble parentage, he was able to devote himself to the field of philosophical inquiry. He is regarded as being self-taught and a pioneer of wisdom. Because of his lonely life, he is historically known as "The Weeping Philosopher," or "The Obscure." Heraclitus insisted that change was the fundamental nature of the universe, famously stating that "No man steps in the same river twice." Philosophers consider this to be one of the earliest instances of the concept of "becoming," roughly defined as the possibility of change for a thing that has "being," or existence. Because of this, he is considered one of the founders of ontology, the branch of philosophy that deals with being and existence. Another of Heraclitus's most influential ideas was his belief about the unity of opposites, saying "the path up and down are one and the same." These ideas and statements have been the subject of numerous interpretations across centuries.