Aristotle (384-322 B.C.) along with Plato and Socrates are considered to be the greatest Greek philosophers, but he is most often compared to Plato. Even though he admired Plato, Aristotle critiqued Plato’s emphasis on the theory of the forms. Plato thought that the particular is less real and is derived from universal things, whereas Aristotle believed the universal things were less real and were derived from the particular. Aristotle’s teachings stated that the material world should not be despised or ignored (like Plato thought) but studied. This resulted in Aristotle doing much more scientific research than his predecessors. 

Since he was the son of a physician, Aristotle had prior medical knowledge, and he and his students would gather information about plants and animals, as well as the history of the Greek constitution and science. Aristotle even attempted to categorize animals into their own species based on their reproduction and hibernation habits, but there were numerous errors. Still, many concepts and much of the language of Western philosophy derives from him. 

Similar to Plato, Aristotle also debated how to have a good life, concluding that happiness is the best thing to have if you want to achieve this goal, which can be obtained by leading a virtuous life, doing good works, and developing a skill that matches your talent.

Years after the time of Aristotle, Sparta conquered the neighboring district of Messenia. The Spartan citizens were given a large amount of the Messenian land and the Messenians were reduced to slavery. Because the slaves outnumbered the Spartans ten to one, the Messenians slaves revolted following their capture, which required a large military presence from the Spartans. Two kings and a board of elders controlled the Spartan Government, and only men over 30 could vote. 

At age seven, every Spartan boy left home to endure 13 years of military training. They were given just enough food to keep them alive and no coat in the harsh winter of the Greek mountains. All this was done to ensure that Sparta had the best fighting men of any army. Despite their impressive fighting force, Sparta lacked a strong navy and always feared a Messenian revolt when the armies were off at war. Eventually, they were defeated along with the other Greek city-states during the Peloponnesian War in 440 BC, and would never rise to their old prowess. 

Socrates (469-399 BC) is widely considered one of the most influential philosophers of his era. Not much is known about his early life, but Plato’s account of Socrates’ life is probably the most accurate. Born to a stone mason father, Socrates might have been the first mainstream philosopher to use what is now known as the “Socratic Ignorance,” which is when someone is so wise that he is fully aware of all his shortcomings.

Morality was Socrates’ main philosophical pursuit. He thought that truth and standards always exist, and people should use reason to find them. This is why he opposed a group called the Sophists, who in contrast did not believe in truth at all. In Socrates’ opinion, they would rather seem to win an argument than actually convince someone of their view. The Sophists taught that all truth was relative, and the only morals in existence are the ones in which someone believed. To counter this argument, Socrates simply stated that he was right and they were wrong. 

When Socrates was sentenced to death by poison in 399 BC for “corrupting the youth,” Plato was 20 years old, a devoted follower of Socrates, and continued the Socratic way of teaching. All of Plato’s writings that we have today are in the form of a dialogue, with a set of characters talking to each other. A main character in his dialogue is even named after Socrates. One of Plato’s main doctrines was the theory of forms, which states that the world is full of non-physical things like ideas, and that physical things are just imitations of the forms. 

Unlike other philosophers of his time, Plato thought that although the highest part of man was his intellect, it was not all of who he is, and sometimes pleasure is a good part of life. Similarly to Socrates, Plato also opposed the ideas of atheism, relativism, materialism, and hedonism. Even though they lived before the time of Jesus Christ, Socrates and Plato influenced later Christian theologians years later.