This is the whole paragraph and the bolded sentence is the sentence that makes me confused:

In 1961, Edward Lorenz, who was both a mathematician and a meteorologist, was studying computer simulations of weather patterns. He found a few simple equations that could describe certain weather patterns. Lorenz plugged these equations into a computer and studied the outcomes, which were very similar to common weather patterns that can be found in the real world. One day he wanted to review a certain simulation that he had previously seen. Rather than starting the entire simulation from the beginning, he attempted to start the simulation somewhere in the middle. The computer was dealing with numbers with six decimal places. However, to save space, it was outputting numbers with only three decimal places. Instead of typing in 0.506127, he entered the number 0.506. Thinking that the difference is less than one part in a thousand, he expected to get the same weather pattern. To his shock and amazement, the weather pattern that emerged was totally different from the one he intended. Lorenz realized that for these simple equations, the way the different parts interacted with each other, and the way outcomes of some of the equations became inputs to other equations, caused major changes in weather patterns depending on starting positions. In other words, an ever-so-slight change in the initial conditions of the equations can radically alter the rest of the simulation. In the real world, this means that a slight change in a weather pattern now can cause a major change later.

Source: The Outer Limits of Reason: What Science, Mathematics, and Logic Cannot Tell Us by Noson S. Yanofsky

I am not a native speaker and I need this part for a paper. can anyone explain this sentence and break it down so I can understand it. I really would appreciate your help.

1 Answer 1


"for these simple equations" - When using the equations mentioned earlier

"the way the different parts interacted with each other" - parts of the equation affect other parts of the equation

"and the way outcomes of some of the equations became inputs to other equations" - The answer from one equation is used as an input for other equations so any change is carried forward

"caused major changes in weather patterns depending on starting positions" - The two previous points put together cause large changes in the final result that are heavily affected by the starting positions.

Putting it all together, you have what is known as a "chaotic system". One change of any size with the original values, affects so many other things in the system that the end result can be very different

  • Thank you very much. But you didn't mention the last part of the sentence. in the last part of sentence, that is "caused major changes in weather patterns depending on starting positions", is it mean that "in weather patterns that depend on starting positions" or is it "depending on starting positins, caused major changes in weather patterns? Feb 27, 2020 at 2:40
  • 1
    Updated the answer. The second option you gave in your comment is the correct one; the changes are what is dependant on the starting position. Regarding the first option, the idea of the text is that all weather systems depend on the starting conditions so it wouldn't make sense to isolate only the ones that depend on the starting position Feb 27, 2020 at 8:16

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