Albert Einstein and his blind friend

This story shows how complex Einstein could be. Not long after his arrival in Princeton he was invited, by the wife of one of the professors of mathematics at Princeton, to be guest of honor at a tea. Reluctantly, Einstein consented. After the tea had progressed for a time, the excited hostess, thrilled to have such an eminent guest of honor, fluttered out into the center of activity and with raised arms silenced the group. Bubbling out some words expressing her thrill and pleasure, she turned to Einstein and said: "I wonder, Dr. Einstein, if you would be so kind as to explain to my guests in a few words, just what is relativity theory ? "

Without any hesitation Einstein rose to his feet and told a story. He said he was reminded of a walk he one day had with his blind friend. The day was hot and he turned to the blind friend and said,

"I wish I had a glass of milk."

"Glass," replied the blind friend, "I know what that is. But what do you mean by milk ?"

"Why, milk is a white fluid," explained Einstein.

"Now fluid, I know what that is," said the blind man. "but what is white ?"

"Oh, white is the color of a swan's feathers."

"Feathers, now I know what they are, but what is a swan ?"

"A swan is a bird with a crooked neck."

"Neck, I know what that is, but what do you mean by crooked ?"

At this point Einstein said he lost his patience. He seized his blind friend's arm and pulled it straight. "There, now your arm is straight," he said. Then he bent the blind friend's arm at the elbow. "Now it is crooked."

"Ah," said the blind friend. "Now I know what milk is."

And Einstein, at the tea, sat down.

This anecdote illustrates two points, but not as was originally intended.

(1) It does illustrate a problem with much of current university pedagogy. The professor pretends to teach and the students pretend to learn. If the examinations are crafted so as to test not what was taught, but rather what was learned, everyone is happy. Grades are good and teaching evaluations are good, and the only loss is the time wasted with no knowledge gain.

(2) The analogy is wrong in suggesting that relativity cannot be made plausible to persons having little scientific or mathematical background. It can be explained conceptually to anyone who is familiar with the action of a magnet, and is willing to accept the fact that electric attaction or repulsion occurs through the action of an intermediary messenger that travels with finite speed. An explanation is given on pages 23-24 of the textbook that uses some algebra, but it can also be made plausible with simple cartoons.

Question: What do swans have to do with Einsteinian Space-Time?   click here .

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