Pre-Socratic to Kant: Key Philosophers & Ideas
Pre-Socratic Philosophers
Philosophy comes from the Greek words “philo” (love) and “sophia” (wisdom). The first recorded use was by Pythagoras in the 6th century BC. The first philosophers were from Miletus: Thales, Anaximander, and Anaximenes. They searched for the natural beginning of things (arche).
- Thales believed the arche was water and that all things were full of gods (hylozoism).
- Anaximenes believed the arche was air.
- Anaximander based the arche on the apeiron (the unlimited or indefinite).
The Pythagoreans also searched for the arche in numbers, specifically the tetractys. They believed that the soul was imprisoned in the physical body.
Heraclitus saw a dynamic naturality in war, the father of all things. He stated that “you cannot step into the same river twice,” and that fire was the principle of all things.
Parmenides believed that “the only thing that exists is immutable being.” Being is, not-being is not. There is no difference between what is knowable (episteme) and what is visible (doxa).
Zeno, a disciple of Parmenides, denied plurality and movement. He presented arguments against plurality, stating that if something is divisible, it can be divided infinitely, and thus, you can never reach an indivisible figure. He also argued against movement with the “dichotomy paradox,” stating that to reach any point, you must first reach the halfway point, and so on infinitely. He argued against place, stating that if everything exists in a place, then that place must also exist somewhere, and so on infinitely.
Empedocles said the world was formed by water, air, earth, and fire, adding ether, which formed the stars. He proposed the principles of love (agreement) and hate (discordance).
Anaxagoras, the first philosopher to live in Athens, was charged with impiety. He believed that the four elements, plus an intelligence superior to all things, created order (nous).
Democritus and Leucippus (Rome) were atomists. They believed that reality was formed by small, indivisible particles called atoms, which move randomly in the void, allowing for plurality and movement.
Sophists, such as Protagoras and Gorgias, lived in Athens. Protagoras claimed that “man is the measure of all things.” Gorgias claimed that “nothing exists; if something existed, we could not know it; if we could know it, we could not communicate it.”
Socrates, Epicureanism, and Stoicism
Socrates left no writings. He changed the traditional master-disciple relationship. His teaching method involved asking questions to bring forth the truth from his disciples (maieutics). He believed that no one acts evil knowingly. He was sentenced to death for impiety and corruption of youth, and he drank hemlock. He influenced the creation of Epicureanism and Stoicism.
Epicureanism states that man should pursue happiness, which consists in pleasure. There are three types of pleasures: natural and necessary, natural and not necessary, and neither natural nor necessary. Rest is preferred over movement to avoid tension. Death is nothing to fear because living involves feeling, and death is the lack of it.
Stoicism had a Greek period (Cleanthes) and a Roman period (Cato, Epictetus, Marcus Aurelius, Seneca). Seneca wrote excellent sentences and advised Nero.
Descartes and Kant
Descartes, the father of modern philosophy, wrote “The Discourse on Method” in 1637. His famous quote is “I think, therefore I am” (cogito ergo sum). He doubted everything except the existence of thought. He studied causality, proposing that A causes B if there is a temporal priority, contiguity (proximate or remote), and a necessary connection.
Immanuel Kant (1724-1804) lived in Prussia (Königsberg). He was a Protestant Pietist. He had three big questions:
- What can I know? (Theoretical)
- What should I do? (Ethical)
- What may I hope? (Religious)
He wrote “Critique of Pure Reason” and “Critique of Practical Reason.” He proposed a thought experiment: we can think of empty space, but not the absence of space. He distinguished between hypothetical imperatives (“If you want to be healthy, don’t smoke”) and categorical imperatives (“Act in such a way…”).