The Presocratics

  Thales                Heraclitus            Parmenides        Democritus

Philosophy began in Greece around the 6th and 5th centuries B.C. when people started to wonder which myths they should believe and why they should believe any myths at all.  Instead of mythical stories about super-hero-like gods, the first philosophers tried to make sense of the world in more scientific or rational terms.

Thales suggested that all things are water.  They are not, of course, but the idea that the nature of all reality can be reduced to one thing or theory still inspires scientists to this day.  Anaximenes suggested everything is air or spirit. 

Heraclitus believed that fire is the basis of everything else.   He seems to have meant this more metaphorically than literally.  He also emphasizes the importance of logos, which means word, meaning, or reason.  Heraclitus is one of the first to argue that appearance and reality are very different.  You cannot step twice into the same river (although it appears that you can).

Anaximander believed in "the Boundless" or indefinite infinite as the divine cause of all things.  Everything, he reasoned, has a beginning or else is a beginning.  The beginning of all things cannot itself have a beginning.   So it is infinite.  And since it is the origin of all things, it must have no definite (particular) nature.  So it is indefinite.

Xenophanes rejected belief in traditional Greek gods.  The gods of Hesiod and Homer do immoral things, and behave too much like human beings.   They have been created in our image.  The real god, he said, in not like us at all.

According to Pythagoras, the world is a cosmos, an ordered whole, and the basis of all things is number.  Like Heraclitus, he was interested in cosmology, the study of the order of the world.

Parmenides, on the other hand, was interested in ontology, the study of being, or of the content of the world.  He argued that this content must only be something (Being itself) not nothing.  And if there is no nothing, there can be no movement or change.  We cannot become what we are not, since what we are not does not exist, thee is no such thing.  We cannot come from or become nothing.   Our senses delude us.  Reason shows that in reality all is unchanging and one.

Empedocles believed that movement and change occur when the four elements of which all things are composed move in accordance with the two laws of Love and Hate.  Anaxagoras argued that there were many more than four elements.

Democritus argued that movement is possible because space (into which things move) is not nothing.  What exists is atoms and void (empty space).   All movement is determined by mechanical laws of motion.  There is no God.     

For more on the Presocratics in cartoon form click here.