Ivory TowerScienceSpiegeloog 402: Appearances

Ivory Tower: Saving the appearances

By March 23, 2020 No Comments

In his allegory of the cave, the philosopher Plato imagines a group of people seated in a cave,  looking at a wall in front of them. Behind them, there’s a fire burning, and in between that fire and themselves are people carrying objects. These objects cast a shadow on the wall the people are looking at. Because they don’t know what’s going on behind them, it is easy for the people to mistake the shadows for reality.

From our modern point of view, the most powerful element in the allegory of the cave is the idea that there is a reality, which we cannot directly observe, behind our observations. Our observations are error-prone, subject to biases, and imprecise; but behind these observations lies another world – the world ‘as it really is’. We can only know this world indirectly, just like the people observing the shadows can only know the objects behind them indirectly. But in principle, we can know the world as it really is.

Scientists often think like this. They see themselves as probing reality through experiments and measurements, getting ever closer to the world as it really is. In philosophy, this idea is called scientific realism, and because many scientists prefer this philosophy, it has been described as ‘science’s philosophy of science’. Returning to the allegory of the cave, we can think of science as using the movements of the shadows to figure out what objects are casting these shadows – and as science progresses, the approximation to reality gets ever better.

But is this an accurate picture? The idea that scientists figure out the deep structure of reality is one way of looking at things, but not the only way. An alternative to scientific realism holds that, although scientists themselves may think they get closer to reality, there is no compelling argument to believe them. All we really know is that the theories scientists come up with provide ever more accurate descriptions of observations and experimental findings. But nothing more. We know that theories that involve atoms have good predictive power, but we don’t know that these atoms “exist”. Nobody has actually seen them; they might as well be figments of our imagination. History suggests that all our old theories eventually get disproven, so why should we believe our current theories?

In terms of Plato’s cave, this viewpoint – known as empiricism – suggests that all we can be sure of is that we see shadows or, more accurately, moving dark spots on the wall. Theories that describe where these shadows come from remain just that: theories. Empiricists hold that no amount of evidence can compel one to definitely accept the existence of atoms, however strong the evidence may appear. Instead, theories merely ‘save the appearances’; that is, they sketch a world in which things would in fact appear to us as they do. But there is no guarantee these theories get better at describing reality. They just get better at describing the movements of the shadows. 

And Plato? He didn’t care about these issues at all. His message was that real insight did not lie in the cave in the first place. Instead, the inhabitants of the cave should get out of the cave to catch a bit of sun. And that’s probably not a bad piece of advice.

In his allegory of the cave, the philosopher Plato imagines a group of people seated in a cave,  looking at a wall in front of them. Behind them, there’s a fire burning, and in between that fire and themselves are people carrying objects. These objects cast a shadow on the wall the people are looking at. Because they don’t know what’s going on behind them, it is easy for the people to mistake the shadows for reality.

From our modern point of view, the most powerful element in the allegory of the cave is the idea that there is a reality, which we cannot directly observe, behind our observations. Our observations are error-prone, subject to biases, and imprecise; but behind these observations lies another world – the world ‘as it really is’. We can only know this world indirectly, just like the people observing the shadows can only know the objects behind them indirectly. But in principle, we can know the world as it really is.

Scientists often think like this. They see themselves as probing reality through experiments and measurements, getting ever closer to the world as it really is. In philosophy, this idea is called scientific realism, and because many scientists prefer this philosophy, it has been described as ‘science’s philosophy of science’. Returning to the allegory of the cave, we can think of science as using the movements of the shadows to figure out what objects are casting these shadows – and as science progresses, the approximation to reality gets ever better.

But is this an accurate picture? The idea that scientists figure out the deep structure of reality is one way of looking at things, but not the only way. An alternative to scientific realism holds that, although scientists themselves may think they get closer to reality, there is no compelling argument to believe them. All we really know is that the theories scientists come up with provide ever more accurate descriptions of observations and experimental findings. But nothing more. We know that theories that involve atoms have good predictive power, but we don’t know that these atoms “exist”. Nobody has actually seen them; they might as well be figments of our imagination. History suggests that all our old theories eventually get disproven, so why should we believe our current theories?

In terms of Plato’s cave, this viewpoint – known as empiricism – suggests that all we can be sure of is that we see shadows or, more accurately, moving dark spots on the wall. Theories that describe where these shadows come from remain just that: theories. Empiricists hold that no amount of evidence can compel one to definitely accept the existence of atoms, however strong the evidence may appear. Instead, theories merely ‘save the appearances’; that is, they sketch a world in which things would in fact appear to us as they do. But there is no guarantee these theories get better at describing reality. They just get better at describing the movements of the shadows. 

And Plato? He didn’t care about these issues at all. His message was that real insight did not lie in the cave in the first place. Instead, the inhabitants of the cave should get out of the cave to catch a bit of sun. And that’s probably not a bad piece of advice.

Denny Borsboom

Author Denny Borsboom

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