Entropy in our Everyday Lives: Active Stability

Because things naturally move to disorder over time, we can position ourselves to create stability. There are two types of stability: active and passive. Consider a ship, which, if designed well, should be able to sail through a storm without intervention. This is passive stability. A fighter jet, in contrast, requires active stability. The plane can’t fly for more than a few seconds without having to adjust its wings. This adjustment happens so fast that it’s controlled by software. Ther...

 American and French Revolutions Led to Different Results

...the structure of a network determines its virality. As recent work by the social scientists Nicholas Christakis and James Fowler has shown, the contagiousness of a disease or an idea depends as much on a social network’s structure as on the inherent properties of the virus or meme. The history of the late eighteenth century illustrates that point well. The ideas that inspired both the American Revolution and the French Revolution were essentially the same, and both were transmitted throu...

 Physics Reduced to Probability

Philosophers have said that if the same circumstances don't always produce the same results, predictions are impossible and science will collapse. Here is a circumstance—identical photons are always coming down in the same direction to the piece of glass—that produces different results. We cannot predict whether a given photon will arrive at A or B. All we can predict is that out of 100 photons that come down, an average of 4 will be reflected by the front surface. Does this mean that phy...

 Repeatability and Probability

When an observation is made on any atomic system that has been prepared in a given way and is thus in a given state, the result will not in general be determinate, i.e. if the experiment is repeated several times under identical conditions several different results may be obtained. If the experiment is repeated a large number of times it will be found that each particular result will be obtained a definite fraction of the total number of times, so that one can say there is a definite probabil...