The Flaws of Perception

... I’ll come back to the subject of the use and abuse of metaphors later, but for now let’s move on to consider another restriction to our sense of vision that has a more immediate impact on how we see the universe: the restriction of the amount of detail we can see when we look at things.


It’s all in the Detail

The amount of detail that you can see when you look at things is the factor that governs such matters as the size of the smallest letters that you can read on a page, or the amount of detail that can be put onto a map without it being too small to see. It affects how much information you can extract from something.
If something is too small to be seen clearly, it’s lost (Figure 5).

Figure 5: What’s in the small print?

The fact that we can only discern detail down to a particular size is so familiar to us that we hardly give it a moment’s thought (until the failing eyesight of middle age starts to make the small print on packaging too difficult to read). It has however, for most of human history, profoundly influenced the very way that we see our place in the universe.
Take a look upwards at the sky to see what I mean.
When we look at the sky we see what for all the world looks like an inverted bowl arching from horizon to horizon. In daylight the bowl is light blue with a fiercely bright, fiery disk of light – the Sun – crossing in front of it, while at night it’s black, with pin-pricks of light – the stars – somehow attached to its surface, and with an interesting silvery disk – the Moon – moving in front of it.
Looking at this sight it would seem reasonable to assume that the earth was at the centre of the universe, with the huge canopy of the sky encircling it. (This doesn’t necessarily entail a flat earth concept of the world by the way. The idea that the earth was a sphere at the centre of this canopy was being toyed with long ago. It wasn’t too difficult a theory to formulate – apart from anything else it seemed probable that the earth was curved because it could be seen that ships at sea disappeared over the horizon once they were about three miles away.)
This well-ordered dome of the heavens with its interesting and manageable array of accompanying lighting arrangements in the form of the Sun, Moon and stars helped foster a view of the universe as a rather parochial place, with the comings and goings on Earth as the most important and significant events that were happening anywhere.
Then, at the beginning of the 17th century, in what is now Italy, Galileo Galilei pointed a telescope at the night sky.
Galileo didn’t actually invent the telescope, as is often mistakenly believed. The instrument had been developed by the Dutch, and several examples of the device were in circulation in Europe when Galileo came to hear of it.
It was clear that the telescope was a splendid device for making distant landscapes look bigger and for observing ships that were far out at sea – a very useful function in a world that was dominated by maritime activity. Galileo however, rather than looking at sailing ships in the distance pointed the device heavenward – and what he saw changed our concept of the workings of the universe forever.
Galileo, by the way, as well as not being the person who invented the telescope, was not necesarily the first person to point one at the sky, contrary to popular belief (again). Other people aimed these novel contraptions in that direction, especially at the Moon. For instance, while Galileo was peering at the sky in Italy the celestial realm was also being studied from Wales. In Carmarthenshire, Sir William Lower (a Cornishman who had settled in Wales) and John Prydderch (or Protheroe) looked at the Moon and made the following observation, described in a letter from Lower to the distinguished scientist Thomas Hariot (or Harriot), who had constructed the telescope and given it to Lower:

 “… and the whole brimme along looks like unto the description of coasts in the Dutch books of voyages. In the full she appears like a tart that my cooke made me last weeke; here a vaine of bright stuffe, and there of darke, and so confusedlie all over. I must confess I can see none of this without my cylinder.”

Observers such as Lower and Prydderch didn’t publish their observations. Galileo on the other hand, realising the implications of what he saw, and being a consummate self-publicist, rushed into print to announce his discoveries.
Telescopic observation showed that the Moon, rather than being the smooth (though somewhat blotchy) object that it was assumed to be before Galileo’s day, was actually covered in extremely large numbers of “confusions” such as craters and mountains.
Galileo didn’t only point his telescope at the Moon, which was an obvious thing to look at: he also aimed it at the stars. He chose to point it at one of the handful of stars that were known to move mysteriously through the sky relative to the other “fixed” stars (which all retained the same positions relative to each other, as though glued to the sky’s canopy). These peripatetic stars were known by the Greek word for wanderers: planets.
To his surprise he saw that the planet to which he’d turned his attention, Jupiter, wasn’t just a pin-prick of light like the other stars but was a distinct disk, like a tiny version of the full Moon. This fact was fascinating in its own right, but what was equally astounding was that the planet seemed to be accompanied by four tiny dots of light strung out in a line on either side of the disk (Figure 6).

 
Figure 6:  Jupiter as seen through a telescope, with its accompanying four dots

On observing the planet over a period of time Galileo noticed that these companion specks moved relative to the planet, but never strayed far from it (Figure 7). He deduced that they were orbiting the planet. Jupiter, it seemed, had satellites.
Needless to say, at about the same time that Galileo was making this observation, other observers such as Lower in Britain were probably noticing the moons of Jupiter too, but without publicising the fact or possibly without immediately realising their significance.

 
Figure 7:  And yet they move! Jupiter’s attendant dots turn out to be satellites

Prior to the time that Galileo made this observation of Jupiter’s satellites it was generally assumed that all celestial objects rotated around the Earth, which was thought to be at the centre of creation, quite naturally. On discovering the moons of Jupiter Galileo had found that some celestial objects revolved around other celestial objects. It was a revelation.
The door was now open for it to be argued that the Earth may revolve around the Sun rather than the Sun around the Earth. This theory was not new. Incredibly, it had been postulated eighteen centuries earlier in ancient Greece by Aristarchus of Samos. It was a concept that was very much in circulation in intellectual circles in Galileo’s time, following the ideas of the Polish polymath Copernicus in the previous century. Copernicus’s idea hadn’t caught on when he first published it seventy years earlier, but here was evidence that there may be something in it.
Having the Earth rotating round the Sun rather than vice versa demoted the Earth from its position at centre stage in the cosmos. This didn’t go down very well at the time as you can imagine, but it’s a state that many of us now prefer, on sober reflection.
One of the most remarkable, though little remarked upon, aspects of the story of Galileo (and the other telescope users) is that the things that they saw through their instruments – the sight of which changed forever the way we see the universe – are things that are just beyond the range of unaided human vision. If our eyes were capable of seeing with only a smidgen more detail we’d be able to see the craters on the Moon and the satellites of Jupiter just by looking at them (The Jovian satellites are of a brightness where they are actually teetering on the edge of visibility to the naked eye, although the glare from the planet itself contributes to making seeing them well-nigh impossible). I would speculate that a hawk, with its hunter’s eye, or even more so an owl, with its excellent night vision, can see the craters on the Moon and possibly the satellites of Jupiter (if they can get around the glare problem) quite easily just by glancing casually at them. But they know not the implications of what they see.
Think how different the history of our awareness of our place in the universe may have been if we’d only had very slightly better eyesight.
Or conversely, try imaging how much less aware we would be of our position in the universe if we didn’t possess vision at all. Imagine how we would perceive things if we were totally blind, and instead of using vision as our means of registering the world we used something akin to the sonar that’s used by bats.
Sonar, or echo location, operates by sending out a pulse of sound and then analysing the echo that’s bounced back from objects. It seems like a crude way to sense things to us, but that’s possibly only because our own sense of hearing is relatively underdeveloped. It’s theoretically possible for echo location to be sensitive enough to be able to build up an “image” of the world that’s in many ways as realistic as that obtained by vision. In fact, if the echo is routed appropriately within the brain the resulting sensation could easily be a three-dimensional model of the world that’s not a million miles from the three-dimensional model of the world that we obtain using vision. Although probably not in colour.
It would reveal to us the position and form of all of the everyday objects around us, such as tables, chairs, trees, hills and animals, simply by analysing the echoes of the sound waves that these objects reflected.
However, things would be different when we shifted our attention away from the objects here on Earth and turned it instead towards those in the sky.
Any sound waves that we sent upwards into the sky would not be returned as echoes. Sound waves need a medium such as air for them to travel through – as a result sounds sent upwards would simply fade away as they approached the vacuum of space, never to return.
Using echo location to look upwards would reveal nothing but an empty void (Not necessarily in an existentially worrying sort of way – perhaps more like a cloudy-sky-at-night sort of way, when there’s just nothing up there to bother paying attention to).
We would have no awareness of the Moon or of the stars. (Although we may wonder what the intriguing source of heat was that passed over our heads each day: the Sun.) We wouldn’t know that there was such a thing as outer space, with other objects in it.
It’s pure luck that, because we have an ability to detect light, we can see the Moon and the stars and the planets spread out before us when we look up at the sky. It’s pure luck because we don’t need to see those things at all – but we can.
Although we can see the cosmos beyond our planet there are however still whole aspects of the nature of the universe that are beyond our senses, purely because of the chance consequences of how our senses work.
It would be extremely useful if we happened to have an extra sense that could somehow allow us to peer into otherwise hidden aspects of reality (whatever they might be), just as our sense of vision allows us to peer outwards at the Moon and stars. If we had such a sense then we may have a much better appreciation of our place in the universe. But we don’t – because peering into hidden aspects of reality is something that we don’t need to do for the purposes of staying alive.
We just have to buckle down and make the most of the senses that we’ve got, by trying to extract extra meaning from the predominantly electromagnetically relayed information that we receive about the universe around us. But it’s not easy.
And it isn’t helped by the fact that when it comes to analysing the information that we receive we’re in some ways rather second rate in the interpretation department.
This can be very clearly seen by looking at a few examples of visual misinterpretation. Exploring this topic is extremely enjoyable because it gives you the perfect excuse to play around with a few optical illusions.
For example, have a look at Figure 8. What do you see when you look at this arrangement of lines?
 

Figure 8:  What do you see?

You probably see a cube.
When you first look at it you may see a cube from slightly above (as shown on the left in Figure 9 with the aid of shading). Look at it for a short time however, and you will probably notice that the lines could equally well be of a cube viewed from below, as on the right in Figure 9.

 
Figure 9:  The cube flips between two views

It’s impossible to pin the shape down to only one cube, as it keeps spontaneously flipping between the two possibilities.
This image, famous in the field of the interpretation of perception, is known as a Necker cube.
There is however something that’s fascinating about the Necker cube illusion that usually goes unremarked upon.
Take another look at the original image in Figure 8.
What do you see again?
A cube that flips between above and below, yes.
Interestingly, that’s probably all you see.
The chances are that you haven’t registered the fact that it isn’t a cube at all.
Look again. It’s just a flat arrangement of lines on a page.
Of course you know that, but you can’t see it that way. You see a cube.
Strangely it takes an almost superhuman degree of effort to see the image as a flat pattern instead of as a flipping cube.

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