PBP - Allegory of the Cave

Update (February 10, 2013): The blog has been moved back to its original domain. Sorry, everybody.

During this past week, I moved this blog to its own subdomain. I've named the blog Exiting the Cave. This is in reference to Plato's Allegory of the Cave from Book VII of the Republic, included below (source).

↓ Skip to below the book ↓

[Socrates is speaking with Glaucon]

[Socrates:] And now, I said, let me show in a figure how far our nature is enlightened or unenlightened: Behold! human beings living in a underground den, which has a mouth open towards the light and reaching all along the den; here they have been from their childhood, and have their legs and necks chained so that they cannot move, and can only see before them, being prevented by the chains from turning round their heads. Above and behind them a fire is blazing at a distance, and between the fire and the prisoners there is a raised way; and you will see, if you look, a low wall built along the way, like the screen which marionette players have in front of them, over which they show the puppets.

[Glaucon:] I see.

Plato's Cave
Plato's Cave

And do you see, I said, men passing along the wall carrying all sorts of vessels, and statues and figures of animals made of wood and stone and various materials, which appear over the wall? Some of them are talking, others silent.

You have shown me a strange image, and they are strange prisoners.

Like ourselves, I replied; and they see only their own shadows, or the shadows of one another, which the fire throws on the opposite wall of the cave?

True, he said; how could they see anything but the shadows if they were never allowed to move their heads?

And of the objects which are being carried in like manner they would only see the shadows?

Yes, he said.

And if they were able to converse with one another, would they not suppose that they were naming what was actually before them?

Very true.

And suppose further that the prison had an echo which came from the other side, would they not be sure to fancy when one of the passers-by spoke that the voice which they heard came from the passing shadow?

No question, he replied.

To them, I said, the truth would be literally nothing but the shadows of the images.

That is certain.

And now look again, and see what will naturally follow if the prisoners are released and disabused of their error. At first, when any of them is liberated and compelled suddenly to stand up and turn his neck round and walk and look towards the light, he will suffer sharp pains; the glare will distress him, and he will be unable to see the realities of which in his former state he had seen the shadows; and then conceive some one saying to him, that what he saw before was an illusion, but that now, when he is approaching nearer to being and his eye is turned towards more real existence, he has a clearer vision, what will be his reply? And you may further imagine that his instructor is pointing to the objects as they pass and requiring him to name them, will he not be perplexed? Will he not fancy that the shadows which he formerly saw are truer than the objects which are now shown to him?

Far truer.

And if he is compelled to look straight at the light, will he not have a pain in his eyes which will make him turn away to take and take in the objects of vision which he can see, and which he will conceive to be in reality clearer than the things which are now being shown to him?

True, he said.

And suppose once more, that he is reluctantly dragged up a steep and rugged ascent, and held fast until he 's forced into the presence of the sun himself, is he not likely to be pained and irritated? When he approaches the light his eyes will be dazzled, and he will not be able to see anything at all of what are now called realities.

Not all in a moment, he said.

He will require to grow accustomed to the sight of the upper world. And first he will see the shadows best, next the reflections of men and other objects in the water, and then the objects themselves; then he will gaze upon the light of the moon and the stars and the spangled heaven; and he will see the sky and the stars by night better than the sun or the light of the sun by day?

Certainly.

Last of he will be able to see the sun, and not mere reflections of him in the water, but he will see him in his own proper place, and not in another; and he will contemplate him as he is.

Certainly.

He will then proceed to argue that this is he who gives the season and the years, and is the guardian of all that is in the visible world, and in a certain way the cause of all things which he and his fellows have been accustomed to behold?

Clearly, he said, he would first see the sun and then reason about him.

And when he remembered his old habitation, and the wisdom of the den and his fellow-prisoners, do you not suppose that he would felicitate himself on the change, and pity them?

Certainly, he would.

And if they were in the habit of conferring honours among themselves on those who were quickest to observe the passing shadows and to remark which of them went before, and which followed after, and which were together; and who were therefore best able to draw conclusions as to the future, do you think that he would care for such honours and glories, or envy the possessors of them? Would he not say with Homer, "Better to be the poor servant of a poor master, and to endure anything, rather than think as they do and live after their manner?"

Yes, he said, I think that he would rather suffer anything than entertain these false notions and live in this miserable manner.

Imagine once more, I said, such an one coming suddenly out of the sun to be replaced in his old situation; would he not be certain to have his eyes full of darkness?

To be sure, he said.

And if there were a contest, and he had to compete in measuring the shadows with the prisoners who had never moved out of the den, while his sight was still weak, and before his eyes had become steady (and the time which would be needed to acquire this new habit of sight might be very considerable) would he not be ridiculous? Men would say of him that up he went and down he came without his eyes; and that it was better not even to think of ascending; and if any one tried to loose another and lead him up to the light, let them only catch the offender, and they would put him to death.

No question, he said.

This entire allegory, I said, you may now append, dear Glaucon, to the previous argument; the prison-house is the world of sight, the light of the fire is the sun, and you will not misapprehend me if you interpret the journey upwards to be the ascent of the soul into the intellectual world according to my poor belief, which, at your desire, I have expressed whether rightly or wrongly God knows. But, whether true or false, my opinion is that in the world of knowledge the idea of good appears last of all, and is seen only with an effort; and, when seen, is also inferred to be the universal author of all things beautiful and right, parent of light and of the lord of light in this visible world, and the immediate source of reason and truth in the intellectual; and that this is the power upon which he who would act rationally, either in public or private life must have his eye fixed.

While Socrates was describing the mindset of a philosopher, his analogy can be translated to other aspects of life. The most obvious comparison is to religion.

Socrates describes prisoners who can only see shadows. These prisoners think the shadows are "real" entities. When one is released, he can only take glimpses to objects outside of these shadows until his eyes adjust. Once he can see a little better, he can see the actual objects that cast those shadows. If he tries to go back to tell the other prisoners, they would think he is a fool and reject his explanations as crazy.

I've called myself a pagan for over half my life. I knew what I believed, but I couldn't find anyone else who believed the same. I tried to make myself believe what everyone else believes, but I couldn't do it. In my attempt, I studied a lot about religion, telling myself that what I read is true. Others were impressed with my knowledge, which made even less sense to me. If you claim to believe in something, why is this new information to you? I know people who hate those who do not believe in Jesus to the point of violence, but those same people have never actually read the Bible. You have to know your beliefs before you can actually believe them.

While soul searching for years, trying to peak out into the world of other faiths, I eventually discovered Hellenismos. I have "seen the light." (I have no idea if that saying originated with Plato's Cave, but it's apt enough that I wouldn't be surprised if they are linked.)

Then, everything I had "taught" myself unravelled. None of it made sense anymore. I also found that if you're a monotheist, atheists look at you like you're completely stupid. If you're a polytheist, both groups look at you the same way.

Now that I have seen the other side of the shadows, I can't go back. The other prisoners reject my ideas as stupid or crazy. I'm OK with that. I'd be lying if I said that I didn't think the same of theirs.

I'm also comfortable with saying that I don't understand everything. While I can see the firelight reflected off what was behind me, I still can't look into the Sun. As a follower of Hellenismos, I know that if something I believe to be true is proven false, I had it wrong, not the Gods. There is no sacred writ, only our interpretations of what is right.

As a side note, this same logic has come up recently in a different form. If you follow Charlie Stross's blog, you may know that he used a similar line of logic to describe why we may not have found extraterrestrial life. However, his prisoners are tapeworms, and the cave is a human colon. (The relevant part is below, but I encourage you to read the entire article.)

What use is a human being — to a tapeworm?

A mature tapeworm has a very simple lifestyle. It lives in the gut of a host animal, anchoring itself to the wall of the intestine with its scolex (or head), from which trails a long string of segments (proglottids) that contain reproductive structures. The tapeworm absorbs nutrients through its skin and gradually extrudes more proglottids, from the head down; as they reach the end of the tape they mature into a sac of fertilized eggs and break off.

The adult tapeworm has no knowledge of what happens to its egg sacs after they detach; nor does it know where it came from. It simply finds itself attached to a warm, pulsing wall, surrounded by a rich nutrient flow. Its experience of the human being is limited to this: that the human surrounds it and provides it with a constant stream of nutrients and energy. A hypothetical intelligent tapeworm might well consider itself blessed to have such a warm and comforting environment, that gives it all the food it needs and takes away anything that it excretes. And if it were of a philosophical bent, it might speculate: what is the extent of my environment? Is it infinite, or are there physical limits to it? And, eventually, are there other tapeworms out there? And finally, the brilliant polymath-level Enrico Fermi of tapeworms might ask, if there are other tapeworms, why aren't they here?

Our tapeworm-philosopher gets its teeth into the subject. Given that the human is so clearly designed to be hospitable to tapeworm-kind, then it follows that if there are more humans, other humans out there beyond the anus, then they, too, must be hospitable to tapeworm-kind. Tapeworm-kind has become aware of itself existing in the human; it is logical to assume that if other humans exist then there must be other tapeworms, and if travel between humans is possible—and we infer that it might be, from the disappearance of our egg sacs through the anus of the human—then sooner or later humans interacting in the broader universe might exchange eggs from these hypothetical alien tapeworms, in which case, visitors! Because the human was already here before we became self-aware, it clearly existed for a long time before us. So if there are many humans, there has been a lot of time for the alien tapeworm-visitors to reach us. So where are they?