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No. 3169:
Percy Bridgman and Meaningless Questions

by Andy Boyd

Today, meaningless questions. The University of Houston presents this series about the machines that make our civilization run, and the people whose ingenuity created them.

What would you have been like if your parents had never met? It's a seemingly reasonable question most children pose at some time or another. But, of course, the question itself doesn't make any sense. If your parents had never met, there'd be no "you."

Parents and Child
Parents and Child   Photo Credit: MDHHS

So how do we know when we're faced with a meaningless question? It was something that captured the imagination of Percy Williams Bridgman, the recipient of the 1946 Nobel prize in physics. Bridgman didn't win the award for abstruse theories about the nature of the universe, but instead for creative experimental work. He developed a pressure chamber for the study of extremely high-pressure physics. When he later became interested in the philosophy of science, it isn't clear he intended to open a philosophical can of worms. In fact his insight, which came to be known as operationalism, had pragmatic origins. But as it filtered its way into disciplines far afield of physics it took on a life of its own.

Percy Bridgman
Percy Bridgman   Photo Credit: Wikimedia

To understand the basic idea behind operationalism, consider the concept of length. We all intuitively know what length is. Not so fast, said Bridgman. We need to be more careful. We need to define how we measure something. Once we specify the operational details of how we do the measuring, only then does length become meaningful.

measuring tape
measuring tape   Photo Credit: Pixabay

Now, this may seem cautious to a fault. But Bridgman had been deeply influenced by Einstein's special theory of relativity. Newton had assumed we all just knew what time was. We didn't need a clock to make it real. Einstein showed that wasn't true at all - that time depended on the relative speed of two different travelers. Prior to Einstein, we'd let our intuition lead us astray. Bridgman didn't want that to happen again.

Bridgman's insistence on requiring operational definitions enforced a rigor that limited the types of questions that could be asked. For those who didn't adhere to that rigor, it was "disquietingly easy ... to ask questions that are meaningless." And he offered a list of potential candidates for his readers to ponder.

  • May time have a beginning or an end?
  • Why does time flow?
  • Are there parts of nature forever beyond our detection?
  • Is there a universe possible in which two plus two does not equal four?
  • Why does nature obey laws?

Bridgman didn't limit his perspective to questions about the natural sciences. "Many of the questions asked about social and philosophical subjects," he wrote, "will be found ... meaningless when examined from the point of operations." Some psychologists embraced Bridgman's ideas, though his assessment of their efforts was that he'd created a "Frankenstein." And after an initial rush of enthusiasm from philosophers, interest quickly waned.

Still, Bridgman had an important point to make. In our quest to answer life's more challenging questions, we first need to ask if, as stated, our questions make sense to begin with.


What's North of The North Pole?


I'm Andy Boyd at the University of Houston, where we're interested in the way inventive minds work.

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Bridgman proposed a longer list than mentioned here. See Bridgman, p. 68.

Percy Bridgman. "The Operational Character of Scientific Concepts." In The Philosophy of Science, edited by R. Boyd, P. Gasper, and J.D. Trout. Cambridge, Massachusetts: MIT Press, 1991. See also: Accessed March 19, 2018.

Hasok Chang. Operationalism. From the Stanford Encyclopedia of Philosophy website: Accessed March 19, 2018.