Plato’s Allegory of the Cave has people chained in chairs facing a blank wall. All that they can see are the shadows cast on the wall of the cave. When they break free from their chains they discover that reality is not what they believed it to be. In particular, they don’t know what the sun is, having never seen it before. The implication is that we cannot know reality and that we only see shadows of it and must make do with that.
It’s a nice analogy, and presages Kant’s noumenon and phenomenon, where phenomenon is what we sense or perceive and noumenon is what gives rise to phenomenon. Noumenon is fundamentally unknowable through human sensation, and perhaps corresponds to Kant’s “Ding an sich” (thing-in-itself), which I think of as the thing that gives rise to perceived phenomena, but is not and cannot be experienced through the senses or by other means (if such exist).
The nice thing about allegories and analogies is that you can play around with them. Of course, if you push them too far they fall apart, but that is part of the fun. I’m going to push the Cave Allegory a little bit.
You see, the people in the chairs are not entirely without information about the outside world, aka reality. If the shadows move across the cave wall and they are not moving, then something else is! They won’t know what is causing this phenomenon, but they will notice that it changes in a fixed cycle. The shadows sweep across the wall, only for everything to go dark, and then everything repeats. Let’s call it a day.
If the people in chairs watch for long enough they may determine that there longer cycles. Sometimes the shadows reach higher up the walls, and sometimes they are lower. Let’s call these longer cycles years.
When one raises his hand one of the shadows changes. Some of the shadows are apparently related to the people in the chairs! The person in the chair will most likely come to associate one of the shadows with him/her self, and by extension would assume that some of the other shadows are people also.
He or she might not realise that his/her body is actually seated in a chair, and that the shadow which he/she associates with his/her self are merely outlines. This is a scary thought – if the analogy holds, is it not possible that the same is true of us? We may be seeing shadows and concluding that we are the shadows. Maybe there is a wider reality outside of our perceptual cave and we only need to turn around to see it.
However, just like the people in the cave, if we did wake to a wider reality, we probably would not understand what we are seeing – the people in the cave, when they freed themselves, found the sun to be incomprehensible.
I just realised that in Plato’s original allegory, the light that threw the shadows was not the sun but a fire. I’m going to acknowledge my mistake but let it stand, as it makes my point that the people in the chairs are not completely without clues about the wider world, even if their interpretations are wide of the mark.
Science and what was previously known as ‘natural philosophy’ are attempts to describe the shadows that we see. One of our shadows is the rising and setting of the sun. I’ve described elsewhere that the extreme doubter, the ultimate sceptic, doubts that we will see another sunrise, or rather, cannot see any way that we can know absolutely that we will see another sunrise (leaving aside for arguments sake the possibility that we drop dead – that is not what the issue is).
I don’t actually believe that we are sitting in any conceptual chairs, so we can’t leap out of them to get a wider view of reality in the sense of the allegory, but we do describe the world in terms of what we see, just as those in the cave do. We have no better access to reality than they do. We just have a better class of shadows as it were.
That’s why I find it amusing when the headlines read that scientists have found the Higgs Boson, or that they have detected gravity waves. Oh really? I do not suggest that the Higgs Boson has not been “found” or that gravity waves have not been detected, of course, but no one have ever seen the Boson or watched a gravity wave passing by.
No, what they have in fact done is theorised about these things, designed experiments that should show a blip in a graph or find an anomalous number in the printout of their experiments, and this is what they see. They see the predicted blip or the anomalous number.
These results however based on existing theories. Starting from theories about matter and what it is made of. Atoms, you say? Oh OK, we have experiments (from long ago) which show that matter is made up of atoms. We know a lot about atoms from experiments and theories, but no one has ever seen one or held one in his/her hands. We are sure, though, that matter is basically made up of atoms.
However, certain results of these experiments lead to the question of what atoms are made of. So we end up with a (very accurate) theory and experiments which show the existence of sub atomic particles. Some of these theories lead to the theory of the existence of the Higg’s Boson. It is required if some of the theories are correct.
I don’t know the details, but experiments have been done which reportedly appear to show the existence of the Higg’s Boson. What they show is results which are consistent with the stack of theories the top one of which predicts the existence of the Higg’s Boson, and the lower theories predict various behaviours down to the lowest level, those that theorise that matter is fundamentally atomic.
Those are our shadows on the wall. We describe what exists by using theories based on what we can see. We see the blip in the graph, and celebrate our theory which is underpinned by other theories down to the lowest and most general theories. However, we can’t get out of our allegorical chairs and turn to actually look at what exists. That’s where the analogy breaks down – there are no chairs and there is no wall. However what we are looking at are shadows.