I think it is very, very difficult to comprehend some things. Like the absence of something which has been ubiquitous in your life. The intellectual idea isn't hard to grasp, and you can even deduce other consequences from the idea, but gaining a visceral (for lack of a better word.. maybe intuitive?) understanding is far more difficult. I came to this belief when I was a teenager and had just gotten into watching foreign films. I watched a film called Hour of the Wolf by Ingmar Bergman. I was watching Bergman films because I expected (from pop culture references) them to be crazy, abstract, unpredictable, and impossible to grasp. They're really nothing like that, of course, but I mention it so you'll understand my mindset.

Instead of being treated to lingering shots of cigarettes, portraits of tired old women, and eggs breaking on chickens, I was actually treated with some insight. It was entirely unexpected, and I imagine that it was not even intentional on the part of Bergman (though if it was, bravo to him!), but I had a very profound realization of what life must have been like before the introduction of electric lights. The main character can't sleep, and huddles around the light of a candle - a positively claustrophobic little area. Now, I had been in circumstances of dark before. I was a Boy Scout and had been away from ubiquitous lighting before. But it was always with the knowledge that I could reach for a flashlight or lantern. I never had to consider that without those things, if I were afraid of what might lie in the dark, I would be forced to simply endure it and wait for dawn - hours away!

I am sure that I only tasted an inkling of what the subjective experience of people in that situation is. But that experience sticks with me decades later. It helped me realize that simply 'knowing' something intellectually can still starve one of the full picture. It helped me realize how profoundly different a life can be with only small changes to environment. It also was one of the big things (along with the humor in The Seventh Seal which doubled me over and which I did not expect) that drove me to become an avid fan of film. The supra-lingual things that a skillfully made film can communicate never cease to amaze me.