Both Heraclitus and Democritus, as the philosophers of historia peri phuseôs, consider nature and human character, habit, law and soul as interrelated emphasizing the links between phusis, kinesis, ethos, logos, kresis, nomos and daimon. On the one hand, Heraclitus’s principle of change (panta rhei) and his emphasis on the element of fire and cosmic motion ultimately dominate his ethics reinforcing his ideas of change, moderation, balance and justice, on the other, Democritus’s atomist description of phusis and motion underlies his principle of moderation and his ideas of health and measured life. In this series, particularly referring to the main principles of motion, moderation and justice, I attempt to describe a coherent pre-Socratic ethical perspective based on the Heraclitean and Democritean fragments. I explore the connections between their physics and ethics also borrowing from Nietzsche’s lectures and writings on the Pre-Socratics. I redefine such Heraclitean and Democritean concepts as harmony, order, perfection, health, self-control, contentment, cheerfulness, concord, sound judgment, wisdom, measure and balance and discuss them under the principles of motion (phusis), moderation (sophrosyne) and justice. In doing so, I also expose the relevance of the Heraclitean notion of logos (interpreting it as the underlying categorical principle of transition between phusis and ethos) in bringing together these ideas and principles. Finally, based on this pre-Socratic Weltanschauung, I assess the possibility of a coherent picture of humanity, its nature and conduct as extending from or fitting into or extending-from-when-fitting-into the cosmos of moving forces and atoms.