Experiment 8: Mr. Einstein is on a railroad car moving to the left with velocity v, and on his car are two light bulbs that, from his perspective, come on simultaneously. To confirm this, he could also rig some sort of detector that would go off only if both beams of light arrive at his position simultaneously.
Question: What will Mrs. Einstein see?
Answer: She will agree that both beams of light reach Mr. Einstein at the same time. However, since from her point of view the light on the right has greater distance to travel, she will see the light on the right come on first!
Conclusion: From the above experiments we see that events which may be simultaneous for one observer can happen in a different sequence for another observer. This leads us to the startling conclusion that there is no such thing as a universal “now” for which everyone will agree on what happens “now”. That is, I can see two events as happening “now” while another observer will see one event happening “now” with the other event yet to occur!
I enjoy these bewildering thought experiments in special relativity. They stretch the mind for its own sake, like riddles, quizzes or a work of art. The more I think about the implications of Mr and Mrs Einstein on moving trains, the more I realise the triviality of our human senses. Our senses and feelings, as beguiling as they are, hardly represent the real world at all.
Recently, the number of books I’ve been reading has inflated my ego. This January, I read 21 books—that’s more than I read between the ages of 0 and 23. I’m also way ahead in this year’s Mad Reviewer Reading Challenge.
Thought experiments brought my ego back to normal again. Not special relativity, this time, but something much more useful…
Guided meditation. Thought experiments that sharpen your worldview.
190 pages, ★★★★★
Two thought experiments from this mid-level Buddhist book stood out for me.
First, everyone on earth is either your friend, neutral, or an enemy. Given that Buddhists believe in infinite reincarnation, everyone on earth has, at different points in the past, been your friend, neutral, and enemy. The author gives a political example:
“China was a close friend of the U.S. during the Second World War, then became an enemy during the Korean War, and now is supposedly a political friend again” — page 69
People also make up, make friends, and fall out within lifetimes. Given that all enemies can become friends, and that all friends can all become enemies, in this lifetime or the next, we can choose to mould the kinds of relationships we want in life.
The book phrases this much better (and longer) than I did, but the concluding ‘meditation’ is this:
“Just as I want happiness and don’t want suffering, so this friend wants happiness and doesn’t want suffering. And equally, this neutral person wants happiness and doesn’t want suffering. And equally, this enemy wants happiness and doesn’t want suffering.” — page 81
Irrefutable logic here cultivates your compassion for enemies, friends and strangers alike. So why not all get along?
Next, the ‘moon-ripples’ analogy, as I’ll call it, reminds us that our perception is just a mirage, a vague approximation of reality. The world behaves like the reflection of the moon in a rippled ocean:
“In the blink of an eye, everything is changing. Or, even more subtly, in each three-hundred-and-sixtieth of a blinking of an eye or of a snapping of the fingers, everything is disintegrating. For a Buddha, the realisation of this is still more subtle, but at our level, this measurement affords a glimpse of subtle change. It is said that all impermanent phenomena possess a nature of such subtle disintegration” — page 171
We fixate on false ideals and try to solidify the future. This is an impossible goal, since the world is unpredictably complex; elusive and in constant flux. The future is never certain, nor should it be. When you encounter something you will never understand or see clearly, just think about the ‘moon-ripples’ analogy.
This interactive book is written for people already familiar with Buddhism. Author Jeffrey Hopkins uses his experience from the Tibetan Buddhist Learning Center in the United States to formulate these exercises. There are dozens of meditations, and pages of prose provide the supporting logic behind each one. Everyone will find something they need in this book—I recommend Cultivating Compassion for all Buddhists. ★★★★★