Thought Experiments - Mental Model Series -4
"I was sitting on a chair in my patent office in Bern. Suddenly a thought struck me: If a man falls freely, he would not feel his weight. I was taken aback. This simple thought experiment made a deep impression on me. This led me to the theory of gravity." - Albert Einstein
Thought experiments are conceptual rather than actual experiments. The constitute a powerful tool for understanding the world. Unlike hypotheses in natural sciences , ethical theories cannot be tested emphirically. Purpose of a thought experiment is to help us to face questions which are difficult to answer and encourage speculation, logical thinking and paradigm shifts .While it may seem counter-intuitive, many of science’s greatest developments in the last century have come from thought experiments rather than physical ones.
To understand this concept , let us look at the following example.
Galileo’s thought experiment demonstrating (rather counter-intuitively) that two objects of different weight must fall at the same speed
Galileo’s thought experiment demonstrating (rather counter-intuitively) that two objects of different weight must fall at the same speed
(Contrary to popular belief, Galileo never actually climbed the leaning tower of Pisa to do this experiment – he didn’t need to.) Galileo knew Aristotle would have predicted that a heavy body (H) would fall faster than a lighter one (L). But, the Italian scientist reckoned, suppose we connect the two bodies by a string, thereby making the compound object H+L. Following Aristotelian physics, one would predict that H+L should fall faster than H by itself because of the compound weight: therefore H+L > H. However, it’s also possible to use the same logic to claim that the compound body should fall at a slower pace than H because of the drag created by L, so that H+L < H. But this yields a contradiction, which means – by reductio ad absurdum – that really H = L = H+L. Neil Armstrong, the first human to set foot on the moon, dramatically showed the whole world that Galileo was right when he let go of a hammer and a feather in the absence of atmospheric friction while standing on our satellite, and, sure enough, they hit the Moon’s surface at the same time. Such is the predictive power of thought experiments!
If you do some research on the internet , you will be surprised to learn how thought experiments contributed to new scientific discoveries. Among scientists, Galileo and Einstein were, arguably, the most impressive thought experimenters. One of the main reasons that scientists go for thought experiments to make their points is that the theories they work with often deal with unobservable phenomena that are either far too large (think black holes), far too small (think fundamental particles), or far to abstract (think space time or the alternate dimensions required by string theory) for people.
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