Some visions of the future provoke a three-letter reaction: Wow!
- The audience is inspired by the vision.
Sometimes, however, the very same vision provokes, in different listeners, an alternative three-letter reaction: Yuk!
- The audience is disgusted by the vision.
The “Yuk!” reaction is usually sparked by intuition – a internal feeling that the vision somehow violates nature, decency, or goodness.
I have a lot of respect for intuition, but I’m in no doubt that it often throws up wrong conclusions.
Optical illusions are a case in point. I’m sure we’ve all got our own favourite optical illusions.
I recently came across the striking example of the two pictures above. As explained in a 2007 Scientific American article,
No, you have not had one grappa too many. These images of the Leaning Tower are actually identical, but the tower on the right looks more lopsided because the human visual system treats the two images as one scene. Our brains have learned that two tall objects in our view will usually rise at the same angle but converge toward the top—think of standing at the base of neighboring skyscrapers. Because these towers are parallel, they do not converge, so the visual system thinks they must be rising at different angles
And here’s another really stunning case – created by Edward H. Adelson of MIT:
Almost unbelievably, the squares marked A and B are the same shade of gray. (Click here for the proof.) How badly our intuition leads us astray in such examples!
I was recently reminded of some more serious limitations of intuition by the following extracts from the opening chapter of Good and Real by Gary Drescher:
To view the universe and its contents – including us – as machines strikes many people as implausibly and unpleasantly cold, a peculiar denial of our true nature…
Distinguishing what is true from what merely feels true is important to our understanding of anything.
Our culture’s pervasive skepticism about reason and mechanism is amply proclaimed in our popular entertainment. In Star Wars, a mentor instructs his blindfolded student to trust his true feelings, his intuition, as a substitute for the missing sensory information. In the film’s mystical fantasy world, that advice turns out to be sound, which makes for fun storytelling.
But reality is quite different. In the early days of aviation, for example, pilots flying inside clouds would regularly lose control of their aircraft and crash. Unable to see the ground or the sky, the pilots literally could not tell which way was up. They relied on their sense of balance and their overall spatial intuition. But as an airplane banks, its flight path curves, and centrifugal effects keep the apparent downward direction pointing straight to the floor of the airplane. To its occupant, the cloud-enshrouded airplane still feels level even as it banks and dives more steeply.
Today, safe flight inside clouds is possible using gyroscopic instruments that report the airplane’s orientation without being misled by centrifugal effects. But the pilot’s spatial intuition is still active, and often contradicts the instruments. Piliots are explicitly, emphatically trained to trust the instruments and ignore intuition – precisely the opposite of the Star Wars advice – and those who fail to do so often perish.
In fact, the pilot’s spatial intuition is itself based on information from mechanical sensors in the pilot’s body – sensors that provide visual, tactile, proprioceptive, and vestibular cues about spatial orientation. Ordinarily, those sensors work well: without them, we’d be unable even to walk. But those particular sensors are inadequate when flying inside clouds – there, we need gyroscopes.
Drescher draws the following conclusion:
The plight of the pilot illustrates a crucial principle: rationally understanding how our feelings and intuitions are mechanically implemented can help us distinguish when our intuitions are trustworthy and useful and when, on the other hand, they mislead us – sometimes calamitously.
It provides a great lead-in to the rest of Dreschler’s book:
The following chapters look into the underpinnings of some of our deepest intuitions – about consciousness, choice, right and wrong, the passage of time, and other matters – in an effort to draw a similar distinction.
I’m still at an early stage in reading the book, so I can’t yet say whether I agree with Dreschler’s more substantial proposals. But I do think that the vivid example of cloud-enshrouded pilots will stick in my mind.