Essential basic assumptions of the modern worldview can already be found in the views of the ancient greek philosopher Democritus. He also assumes that the world is made of small atoms, invisible to the human eye. They fill up a space or leave it empty. He defines the atoms as indivisible, existing eternally, and they can be combined and separated as often as desired. Also, there are different kinds of atoms, and the combination allow to build everything that we can find in the world. According to Democritus, nothing exists but atoms and empty space. The spirit, which is part of Anaxagoras worldview, is denied. Democritus wants to explain the arrangements of atoms and the phenomenon of life with the particles themselves. To him, the soul is also made of atoms, and with death it dissolves and distributes across the world, just as the physical body does at the end of its lifespan.
It can be said that Democritus was a materialist and that he presented the fundamental ideas of todays materialism. In search of the indivisible we have found out by now that the particle which we still call an atom can in fact be split up into smaller particles. We talk about different smallest particles now, but the basic idea of this worldview has remained the same to this day. With regard to the meaning of life Democritus says that the striving for knowledge creates a feeling of wellbeing and an experience of happiness, which is man’s highes good. When we observe the behavior and the values of mankind in the western cultures today, then we can recognize a similar attitude to life and to the world. However, today it is not uncommon to substitute the strive for knowledge with consumption of stuff and sensual pleasure.
Democritus is considered the last famous pre-Socratic philosopher. During his time the Sophists lived and worked in ancient Athens. They consider questions about God or the Gods and about the big questions of natural philosophy to be unfathomable, beyond what humans can gain knowledge of. So we can call them Agnostics. They refuse to speculate about fathomless topics and instead wonder about the place of humans in a civilization. They question universally valid norms and values and consider the human nature to be shaped by the surroundings. Humans learn to adopt customs and manners, and they also learn to be ashamed of what society considers immoral actions. This attitude is the result of an observation. The Sophists notice that people behave differently, depending on the city they live in and the rules that the city maintains. They also judge situations and actions differently, considering the values they have adopted.
Socrates takes an opposing position and tries to demonstrate the universal validity of some norms and values. To him, the ability to differentiate right and wrong, justice and injustice, is embedded in reason, in other words in good sense. Justice cannot be randomly defined by a society. The Sophists say that right and wrong is something fluent, constantly changing, different from state to state and epoch to epoch. Socrates does not accept that. Right and wrong belongs to the eternal. Also human reason itself is timeless and unchanging. We can call Socrates a rationalist. His influence was so massive and his views so formative that we divide philosophy in a time before and a time after Socrates.
Plato, the most famous student of Socrates, presents a worldview that is fundamentally different from Democritus view. He is also looking for the everlasting truth behind the constantly transforming objects of the world. However, he does not dive into an analysis of matter, but instead turns to the human mind, to the idea that are not given to us by sensory perception. The world of ideas exists for Plato parallel to the sensory world, and it is accessible for humans thanks to reason, thanks to the reasonable thinking. Reality is comprised of two areas, which we perceive in two different ways. On the one hand we have world of objects, perceivable with our sensory organs, which presents itself with all the material that keeps transforming and reshaping. On the other hand we have the world of ideas, which is eternal and perceivable for our reasonable soul. We can call Plato a dualist.
Also humans are a being of two worlds for Plato. We have access to the flowing, transitory sensory world through our physical body, and we have access to the eternal world of ideas through our immortal soul. Without body, the soul lives in the world of ideas. It remains connected to it even while living in a body, and that enables us to recognize the realization of ideas in the objects of the sensory world. Without the access to the world of ideas this would not be possible, because each realization is just a shadow of the idea behind it, and only with reason can the soul find and discover the full scope of an idea. For Plato, true knowledge can be found only with the recognition of an idea. He shows a faith in the reasonable thinking of mankind which the skeptical Sophist are lacking.
With his thoughts about an ideal state Plato presents the idea of a trinity. A threefold structure as we also find it today in modern concepts for the separation of powers. Unfortunately we lost the worldview that Plato combined with his idea. As a result, modern states are far from realizing the trinity that Plato suggested. To achieve that, we need a worldview that does not count on material particles only as the last cause for everything that exists. To understand Plato, we as free human beings must carry out the change that Socrates triggered so many years ago.