Saturday, July 7, 2012

Archimedes' Bathtub, Newton's Apple and Einstein's Chair

When do Great Ideas come ?

.... after Incubation 

Archimedes had his bath, Galileo had his leaning tower, Newton had his apple, and Einstein had his chair. All these Inventors were (a) intensely focused on solving specific physics problems (b) they had each looked at a variety of promising ideas, but reached an impasse after some stage (c) they smartly decided to move away from the scene - took a break (d) after some time, a fresh idea popped into their Mind (e) they recognized the potential of the idea and held on to it (f) they diligently worked on it  and finally developed a real breakthrough concept. Many Inventors have shared the vale of incubating their idea and described specific instances where the incubation phase is followed by a sudden enlightenment.

We have heard the stories of Archimedes, Galileo and Newton too often - so let us focus on Einstein's story. You might have heard of Einstein's Violin but not about his chair - the chair that gave his most fortunate thought - the discovery of the Equivalence Principle. I read a very interesting account of it in Dr Robert Heaston's paper on how Einstein discovered the Equivalence Principle.

Read the excellent article - Why Did Einstein Put So Much Emphasis on the Equivalence Principle? by Dr. Robert J. Heaston -

Einstein's Fortunate Idea

Einstein considered the discovery of the equivalence principle as “die gl├╝ckichste Gedanke” in his life. Whether translated as “the happiest thought”, “luckiest thought,” or “the most fortunate thought,” Einstein formulated the equivalence principle as the result of an epiphany he experienced in October 1907. He regarded the equivalence principle as the beginning step in adding gravitation to the special theory of relativity to create general relativity.

 Einstein's own account of  “How I Created the Theory of Relativity.” This is what Einstein said then about an October day fifteen years before. “I was sitting in a chair in the patent office at Bern when all of a sudden a thought occurred to me: ‘If a person falls freely he will not feel his own weight.’ I was startled. This simple thought made a deep impression on me. It impelled me toward a theory of gravitation.”

Einstein on "How I created Relativity" -

Dr Robert Heaston has beautifully visualized the scene when Einstein got this fortunate idea. could have Sometime during October 1907, probably the second or third week, Einstein was on the job and was sitting at his desk with a new batch of patents to review. Before he started reading one of the patents, Einstein leaned back in his chair, pushed some papers out of the way and swung his feet upon his desk top. He pondered the patent and leaned back a little more—and a little more, until he felt the feeling of exotic motion when experiencing free fall. He had a momentary sense of zero gravity and then the sudden panic of trying to grab hold of something to brace his fall. As Einstein sprawled on the floor, he made a quick check of his body for damage. Then, two magnificent, unexpected, and exhilarating thoughts welled up in him. “Gravitation is acceleration. Gravitational mass is the same as inertial mass—I fell on my mass!” He laughed out loud and looked around to see if anyone saw what happened. He thought to himself, “Newton had his apple. I have my chair.” And, he laughed again, got up, put his inspirational chair into an upright position, sat down and started to write.”

The Equivalence Principle - Why is it a fortunate idea ?

You may wonder why Einstein called it a very fortunate idea - to understand how remarkable the Equivalence Principle is - read James Overduin's essay at 

" To understand how remarkable the equivalence principle really is, imagine how it would be if gravity worked like other forces. If gravity were like electricity, for example, then balls with more charge would be attracted to the earth more strongly, and hence fall down more quickly than balls with less charge. (Balls whose charge was of the same sign as the earth's would even "fall" upwards.) There would be no way to transform away such effects by moving to the same accelerated frame of reference for all objects. But gravity is "matter-blind" — it affects all objects the same way. From this fact Einstein leapt to the spectacular inference that gravity does not depend on the properties of matter (as electricity, for example, depends on electric charge). Rather the phenomenon of gravity must spring from some property of spacetime. "

Key Takeaway

Einstein could visualize the ground-breaking concept of the Principle of Equivalence in an instant. Such instants play a key role in inventive thinking. Of course, Einstein has to follow it up with the rigorous physics mechanisms and mathematical calculations - but the seed thought was visualized in entirety in that instant. Einstein is well known for his thought experiments - his extraordinary ability to visualize what if experiments  - e.g what if somebody travels at the speed of light ?

Conduct "What if" experiments (in your Mind) to trigger out-of-the-box thinking - list down a whole bunch of "what if" conditions and try to visualize in detail each one of those.

Image Credits:

Equivalence Principle cartoon - 


  1. Very interesting. I read an article that Kekule the chemist who was working on the structure of benzene found in his dream a hexagonal structure. Next day he could relate his dreams to his experiments and discovered the structure of benzene-sundaram

  2. Kekule's story goes like this (at least the version that I heard)- he was working hard to solve the structure of benzene - he was unable to make progress beyond a particular stage - he was exhausted (physically & mentally) and he dozed off - in his dream he saw a snake trying to catch its tail by its mouth - thus he saw something like a closed loop - he got up at this instant and wondered if Benzene can have a cyclic structure - did calculations & experiments that confirmed his idea.