In his work Republic (written sometime around 380 BCE), Plato recorded what some consider to be the greatest philosophical statement of all time. Through the use of the Socratic method in the book, Plato has a fictionalized version of the real Socrates relaying a scenario to Glaucon, Plato’s brother. In this scenario, a group of people have been chained to the wall of a cave for the entirety of their lives. If this wasn’t bad enough, they are also positioned so that they’re facing the cave wall. They have never once seen what is behind them. It turns out that there is actually a bonfire behind them, and as various objects pass to and fro in front of the fire, shadows are cast on the cave wall, the very wall these chained people are facing. Since they have never not been chained to that cave wall, and since they therefore have no idea what may or may not exist beyond the confines of that cave, the shadows on the wall are the only reality these people will ever know, a manufactured reality that has no relation to what truly is.
Socrates goes on to tell Glaucon that a philosopher is, essentially, like one of those chained prisoners who is somehow freed. As such, he comes to understand the shadow reality he has been living, and thus recognizes it as false. He then exits the cave whereupon he is introduced to an entirely new scope of reality, one that he never before dreamed existed (and one, we must note, that may or may not be as false as the shadow reality he knew on the cave wall—a possibility that suggests there is always a new scope of reality to discover).
Through the use of the allegory, Plato was basically commenting that the majority of people live lives of relative ignorance. They neither know any other reality nor want to know any other reality. The reason they don’t want to know any other reality is that they don’t even know another reality is even possible! All they know is that which they have experienced: mere shadows upon the wall of a cave. The philosopher, then, is merely that person who, through his own fortitude and resourcefulness or through the help of others (“Take the red pill, Neo.”), has left the cave and thus gone on to understand a wider scope of existence.
What’s interesting is that Plato even mentions that likelihood that, once having been freed, a prisoner might look at the fire for the first time and note that it hurts his eyes. At first he likely doesn’t even understand the fire. As the truth begins to dawn on him, however, cosmic pain enters his mind, for he begins to comprehend the horrific scope of his erroneous views on reality. “Everything I’ve ever known,” he says to himself, “has been a lie.” He may even refuse to believe what he sees; indeed, he might even go back to his chains, preferring their comfort over the frightening and overwhelming implications of the new reality. Who among us can’t identify with this freed prisoner? How many among us, having been liberated from one thing or another in our personal lives, will actually go running back to it rather than square with the vulnerability of living without it (I’m reminded of Kierkegaard’s assertion that anxiety is basically our negative reaction to the implications of freedom)? The Allegory of the Cave is therefore a remarkably profound and apropos commentary on the human condition.
In the dialogue, Socrates also explains to Glaucon that if a freed prisoner, having exited the cave and thus fully adjusting himself to the truth of his new reality, went back into the cave to try and free his brethren, the darkness of the cave would blind him in the same way the light did when he first left the cave. The prisoners would then infer from the freed man’s blindness that his journey outside the cave was dangerous and detrimental. As a result, they would more than likely resist his attempts to free them. They might even go so far as kill him rather than allow him to disrupt their status quo (I suppose that they are somehow able to commit murder while being chained to the wall is to be taken for granted). This was Plato’s way of communicating what so many people either fail to understand or refuse to understand: the pervasive instinct of humanity is to resist the truth, mostly because the truth, whatever it may be, is contrary to the comfort of our current situation. For this reason alone, the Allegory of the Cave is, to me, by far the most effective and transformative concept in all philosophy—or indeed in all of Western thought. Everything we need to know about our stymied progress as a species is communicated clearly here.
 The Socratic method: a method of teaching through the use of rhetorical questions within a dialogue between two or more persons. This style of teaching is contrary to the most accepted form of teaching used in today’s universities, which is the lecture.