“I think therefore I am”
Author: René Descartes
Descartes began philosophising by using the method of doubting everything he approached, this theoretically would help him to figure out what he could know with a complete certainty. He surmised that he could actually be wrong about what exactly he was thinking, though he was sure that he was thinking, therefore he must truly exist in some sense. After this he went on to question what he was, using this logic he could be sure that he was a thinking thing as opposed to something physical. He knew he existed but he couldn’t be truly sure if he had a body (using his logic). You can read further into his philosophy in his Meditations.
“The unexamined life is worth nothing”
This quote is one of Socrates most famous and is one of the most driving of his beliefs. At its bare bones it simply means that one must reflect upon their own lives, a belief that was partially inspired by the shrine of the oracle in Delphi which had inscribed on it “Know thyself”. This was in reference to the prophecies, meaning you must know yourself to interpret them. Socrates was well known for his relentless questioning; he did this to force others into examining their own beliefs in order to better themselves.
“If a tree falls in the forest and no one is there to hear it, did it make a sound?”
Author: George Berkeley
The quote itself is not technically accurate, Berkeley never posed the question but rather used the notion as an example. It relates to the true quote of his “To be is to be perceived”. He was an idealist and believed that nothing is truly real apart from minds and their ideas, he believed that something exists only if it is someone’s idea. If a tree fell in the would and not a living soul was around to hear it, he theorised that not only would there be no sound made but not tree to make it either.
“God is dead”
Author: Friedrich Nietzsche
This is a quote that is often taken as a sentiment of atheism, though Nietzsche himself was an atheist it doesn’t actually refer a specific opinion on religion but more the notion of it. The quote is something of a metaphor that refers to a belief in god amongst the masses. By saying “God is dead” Nietzsche is stating that the God of the Christian faith is a worn-out concept that is on the decline and no longer the centre of societal values.
“We live in the best of all possible worlds”
Author: Gottfried Wilhelm Leibniz
This quote may seem somewhat optimistic, particularly in todays world, however Leibniz believed that before God created the world and all its inhabitants, he contemplated every possible outcome and chose to create it in this way. He concluded this using the principles of sufficient reasoning, believing that say, had God not allowed human evil into the world there would also be no free will and therefore it would not be the best possible world created.